Microencapsulation involves enclosing solids, liquids, or gases within thin coatings to give small capsules or spheres known as microcapsules or microspheres. It can be used to mask tastes or odors, protect active ingredients from the environment, or allow for controlled release of substances. Several methods are used for microencapsulation including spray drying, pan coating, fluidized bed coating, coacervation, and solvent evaporation. The choice of coating material and method used depends on the properties desired for the encapsulated substance and its intended application.
computer simulation in pharmacokinetics and pharmacodynamicsSUJITHA MARY
This document discusses the use of computer simulation in pharmacokinetics and pharmacodynamics at four different levels: whole organism, isolated tissues/organs, cellular, and protein/gene levels. At each level, mathematical models are used to represent biological processes and predict behavior over time. The goal is to better understand drug behavior and improve drug development by replacing animal and human trials with computer simulations. Challenges include integrating data from different structural levels and ensuring high quality input data.
This document summarizes computational modeling techniques for predicting drug absorption, distribution, and excretion properties. It discusses both quantitative and qualitative modeling approaches. For absorption, it describes models for predicting solubility, permeability, and factors like ionization state and transporters. For distribution, it covers volume of distribution, plasma protein binding, and blood brain barrier permeability modeling. For excretion, it discusses challenges modeling clearance but focuses on estimating clearance from in vitro data. The document provides examples of specific modeling tools and considers limitations of current approaches.
This document discusses microspheres and microcapsules. It defines microspheres as solid spherical particles ranging from 1-1000μm that can be matrix systems with drug dispersed throughout or reservoir systems with drug enclosed. The document describes various types of microspheres including bioadhesive, magnetic, floating, and radioactive. It also discusses common polymers used and various preparation techniques such as spray drying, solvent evaporation, and polymerization. Finally, the document outlines methods for evaluating properties of microspheres like particle size, drug loading, and in vitro drug release.
This document discusses aquasomes, which are nanoparticulate drug delivery systems composed of a ceramic core coated with polyhydroxy oligomers. It describes how aquasomes are prepared through a simple process involving the preparation of a ceramic core, coating it with carbohydrates, and immobilizing drug molecules. The document evaluates various properties of the ceramic core, sugar coating, and drug-loaded aquasomes. Aquasomes offer advantages like increased drug efficacy and avoidance of multiple injections. They have applications in oxygen carrying, immunotherapy, and delivery of drugs, enzymes, insulin, and vaccines.
Brain Targeted Drug Delivery System
Prepared by :
Surbhi
M.Pharmacy II sem
Submitted to :
Dr. Anupama Diwan
MAGIC BULLET : CONCEPT OF PAUL EHRLICH
Brain Targeting: Challenges
Blood brain barrier (BBB): Brain is tightly segregated from the circulating blood by a unique membranous barrier.
The brain and spinal cord are lined with a layer of special endothelial cells that lack fenestrations and are sealed with tight junctions that greatly restrict passage of substances from the bloodstream.
These endothelial cells, together with perivascular elements such as astrocytes and pericytes, constitute the BBB.
Rate-limiting factor in determining permeation.
The factors affecting particular substance to cross BBB
Drug related factors at the BBB
Concentration at the BBB and the size,
Flexibility,
Conformation,
Ionization (nonionized form penetrates BBB)
Lipophilicity of the drug molecule,
Cellular enzyme stability and cellular sequestration,
Affinity for efflux mechanisms (i.e. P-glycoprotein),
Hydrogen bonding potential (i.e. charge),
Affinity for carrier mechanisms, and
Effect on all of the above by the existing pathological conditions
Transport Mechanisms
Several specialized transport mechanisms of solute transfer across endothelial cells and into the brain interstitium are also present within the BBB Carrier system for monosaccharides, monocarboxylic acid, neutral amino acids, basic amino acid, acidic amino acids, amines, purine bases, nucleosides, vitamins and hormones.
The more lipophilic substances that are present in the blood can diffuse passively directly through the lipid of the cell membrane and enter the endothelial cells and brain by this means.
Strategies for Brain Targeting Mechanisms for drug targeting in the brain involve going either "through" or "behind" the BBB.
Neurosurgical or Invasive Strategies
BBB disruption :Disruption of BBB by osmotic means (Hyperosmolar solutions),
Intraventricular drug infusion
Intracerebral Implants: Biodegradable implants,
Physiologic based Strategies
Psuedo nutrients eg L-dopa
Cationic antibodies.These undergo Absorption mediated trancytosis through BBB owing to positive charge.
Chimeric peptides.
Computational modelling of drug disposition active transportSUJITHA MARY
This document discusses computational modeling of active transport mechanisms that influence drug disposition. It summarizes modeling efforts for several major drug transporters, including P-glycoprotein (P-gp), Breast Cancer Resistance Protein (BCRP), nucleoside transporters, peptide transporter 1 (hPEPT1), Apical Sodium-dependent Bile Acid Transporter (ASBT), Organic Cation Transporters (OCTs), Organic Anion Transporting Polypeptides (OATPs), and the Blood Brain Barrier choline transporter. While transporter modeling has advanced, fully incorporating active transport into predictive models remains an ongoing challenge.
Biopharmaceutics of antisense molecule and aptamersSUJITHA MARY
This document provides an overview of antisense molecules and aptamers. It defines antisense molecules as synthetic DNA or RNA segments that bind to mRNA to block protein production. Aptamers are single-stranded nucleic acid molecules that bind targets with high affinity and specificity, developed through the SELEX process. The document outlines the mechanisms of antisense therapy and aptamer target binding. It also discusses the advantages and limitations of both antisense molecules and aptamers, as well as strategies to overcome aptamer limitations, before concluding with their therapeutic potential.
Problems of variable control in dissolution testing discusses issues that can affect the results of dissolution testing. Dissolution testing is important for characterizing drug release from oral solid dosages and ensuring bioavailability. However, variables like equipment alignment and agitation levels can increase variability in dissolution rates measured. Both the paddle and basket methods are sensitive to different issues like tilting, clogging, or air bubbles. No single method works best for all products, so selection depends on the specific drug formulation and optimizing test conditions.
computer simulation in pharmacokinetics and pharmacodynamicsSUJITHA MARY
This document discusses the use of computer simulation in pharmacokinetics and pharmacodynamics at four different levels: whole organism, isolated tissues/organs, cellular, and protein/gene levels. At each level, mathematical models are used to represent biological processes and predict behavior over time. The goal is to better understand drug behavior and improve drug development by replacing animal and human trials with computer simulations. Challenges include integrating data from different structural levels and ensuring high quality input data.
This document summarizes computational modeling techniques for predicting drug absorption, distribution, and excretion properties. It discusses both quantitative and qualitative modeling approaches. For absorption, it describes models for predicting solubility, permeability, and factors like ionization state and transporters. For distribution, it covers volume of distribution, plasma protein binding, and blood brain barrier permeability modeling. For excretion, it discusses challenges modeling clearance but focuses on estimating clearance from in vitro data. The document provides examples of specific modeling tools and considers limitations of current approaches.
This document discusses microspheres and microcapsules. It defines microspheres as solid spherical particles ranging from 1-1000μm that can be matrix systems with drug dispersed throughout or reservoir systems with drug enclosed. The document describes various types of microspheres including bioadhesive, magnetic, floating, and radioactive. It also discusses common polymers used and various preparation techniques such as spray drying, solvent evaporation, and polymerization. Finally, the document outlines methods for evaluating properties of microspheres like particle size, drug loading, and in vitro drug release.
This document discusses aquasomes, which are nanoparticulate drug delivery systems composed of a ceramic core coated with polyhydroxy oligomers. It describes how aquasomes are prepared through a simple process involving the preparation of a ceramic core, coating it with carbohydrates, and immobilizing drug molecules. The document evaluates various properties of the ceramic core, sugar coating, and drug-loaded aquasomes. Aquasomes offer advantages like increased drug efficacy and avoidance of multiple injections. They have applications in oxygen carrying, immunotherapy, and delivery of drugs, enzymes, insulin, and vaccines.
Brain Targeted Drug Delivery System
Prepared by :
Surbhi
M.Pharmacy II sem
Submitted to :
Dr. Anupama Diwan
MAGIC BULLET : CONCEPT OF PAUL EHRLICH
Brain Targeting: Challenges
Blood brain barrier (BBB): Brain is tightly segregated from the circulating blood by a unique membranous barrier.
The brain and spinal cord are lined with a layer of special endothelial cells that lack fenestrations and are sealed with tight junctions that greatly restrict passage of substances from the bloodstream.
These endothelial cells, together with perivascular elements such as astrocytes and pericytes, constitute the BBB.
Rate-limiting factor in determining permeation.
The factors affecting particular substance to cross BBB
Drug related factors at the BBB
Concentration at the BBB and the size,
Flexibility,
Conformation,
Ionization (nonionized form penetrates BBB)
Lipophilicity of the drug molecule,
Cellular enzyme stability and cellular sequestration,
Affinity for efflux mechanisms (i.e. P-glycoprotein),
Hydrogen bonding potential (i.e. charge),
Affinity for carrier mechanisms, and
Effect on all of the above by the existing pathological conditions
Transport Mechanisms
Several specialized transport mechanisms of solute transfer across endothelial cells and into the brain interstitium are also present within the BBB Carrier system for monosaccharides, monocarboxylic acid, neutral amino acids, basic amino acid, acidic amino acids, amines, purine bases, nucleosides, vitamins and hormones.
The more lipophilic substances that are present in the blood can diffuse passively directly through the lipid of the cell membrane and enter the endothelial cells and brain by this means.
Strategies for Brain Targeting Mechanisms for drug targeting in the brain involve going either "through" or "behind" the BBB.
Neurosurgical or Invasive Strategies
BBB disruption :Disruption of BBB by osmotic means (Hyperosmolar solutions),
Intraventricular drug infusion
Intracerebral Implants: Biodegradable implants,
Physiologic based Strategies
Psuedo nutrients eg L-dopa
Cationic antibodies.These undergo Absorption mediated trancytosis through BBB owing to positive charge.
Chimeric peptides.
Computational modelling of drug disposition active transportSUJITHA MARY
This document discusses computational modeling of active transport mechanisms that influence drug disposition. It summarizes modeling efforts for several major drug transporters, including P-glycoprotein (P-gp), Breast Cancer Resistance Protein (BCRP), nucleoside transporters, peptide transporter 1 (hPEPT1), Apical Sodium-dependent Bile Acid Transporter (ASBT), Organic Cation Transporters (OCTs), Organic Anion Transporting Polypeptides (OATPs), and the Blood Brain Barrier choline transporter. While transporter modeling has advanced, fully incorporating active transport into predictive models remains an ongoing challenge.
Biopharmaceutics of antisense molecule and aptamersSUJITHA MARY
This document provides an overview of antisense molecules and aptamers. It defines antisense molecules as synthetic DNA or RNA segments that bind to mRNA to block protein production. Aptamers are single-stranded nucleic acid molecules that bind targets with high affinity and specificity, developed through the SELEX process. The document outlines the mechanisms of antisense therapy and aptamer target binding. It also discusses the advantages and limitations of both antisense molecules and aptamers, as well as strategies to overcome aptamer limitations, before concluding with their therapeutic potential.
Problems of variable control in dissolution testing discusses issues that can affect the results of dissolution testing. Dissolution testing is important for characterizing drug release from oral solid dosages and ensuring bioavailability. However, variables like equipment alignment and agitation levels can increase variability in dissolution rates measured. Both the paddle and basket methods are sensitive to different issues like tilting, clogging, or air bubbles. No single method works best for all products, so selection depends on the specific drug formulation and optimizing test conditions.
hisory of computers in pharmaceutical research presentation.pptxDhanaa Dhoni
Computers have been used in pharmaceutical research and development since the 1940s. Early computers were large mainframe systems that were expensive and shared between organizations. By the 1960s, some pharmaceutical companies had acquired early computers like the IBM 650 to assist with scientific tasks. Today, computers are essential for tasks across the pharmaceutical industry from drug design and clinical trials to manufacturing, sales, and more. Advanced statistical modeling and software continue to be important tools in pharmaceutical research and development.
The document discusses various drug delivery systems including niosomes, aquasomes, and phytosomes. Niosomes are vesicles composed of non-ionic surfactants that can encapsulate medications and offer advantages over liposomes such as lower cost and greater stability. Aquasomes are three-layered nanoparticle structures consisting of a ceramic core coated with an oligosaccharide film that can deliver fragile molecules while maintaining their integrity. Phytosomes utilize phospholipids to surround active herbal constituents, improving their absorption and bioavailability compared to traditional herbal extracts.
computer in pharmaceutical formulation of microemlastionsurya singh
This document discusses the use of computer-aided techniques in the development of microemulsion drug carriers, with a special emphasis on optimization. It describes how artificial neural networks (ANN) can be used as tools to accurately predict the microemulsion area based on formulation composition. Various optimization techniques are explored, including factorial designs, response surface methodology, and the use of ANN for multi-objective optimization problems. Microemulsions offer benefits as drug carriers, and optimization is important to develop formulations that solubilize both water-soluble and oil-soluble compounds for delivery.
Intranasal drug delivery system - Introduction, Nasal enzymes and nasal ph, cross sectional view of nose, factors affecting nasal absorption, general formulations of intranasal drugs, Intranasal dosage forms, nasal sprays, spray pump devices, nasal aerosols, compressed air nebulizers, nasal powder, nasal gels, applications of intranasal drug delivery system, delivery of intranasal vaccines, intranasal anaesthesia, Evaluation of intranasal formulation, ussing chamber, Advantages and disadvantages of intranasal drug delivery system
This document discusses tumour targeting for drug delivery. It begins with an introduction defining different types of tumours and the differences between normal and cancer cells. It then discusses the stages of tumour development and approaches to tumour targeting, including passive targeting via the enhanced permeability and retention effect, active targeting using ligands against tumour cell receptors, and triggered drug delivery responsive to the tumour microenvironment. Examples of approved drugs using different carriers for passive targeting are also provided.
This document discusses targeted drug delivery systems. It begins by defining targeted drug delivery as selectively delivering medication only to its site of action to increase concentration there and reduce it elsewhere. This improves efficacy and reduces side effects. It then lists the ideal characteristics of targeted systems and the advantages they provide like reduced toxicity and dosage. The document outlines various carrier systems and the biological processes involved in cellular uptake, transport across barriers, extravasation into tissues, and lymphatic uptake. It concludes by describing different strategies for targeted delivery, including passive, active, and physical targeting approaches.
This document discusses descriptive versus mechanistic modeling approaches in drug discovery. It provides examples of descriptive modeling, which aims to describe data patterns without understanding the underlying mechanisms, and mechanistic modeling, which works with domain experts to translate scientific knowledge into mathematical representations of the data-generating processes. The document presents tumor growth curve analysis as an example where mechanistic models like Richards and Gompertz curves can incorporate understandings of competing catabolic and anabolic processes to better capture the fundamental characteristics of growth.
This document discusses the application of computer-aided techniques in developing pharmaceutical emulsions and microemulsions. It provides several examples of how experimental design and artificial neural networks have been used to optimize emulsion formulations and processing parameters. Specifically, researchers have used factorial design, response surface methodology, and artificial neural networks to determine the ideal concentrations of formulation components, processing conditions, and emulsifier mixtures to produce emulsions with desirable properties like stability, viscosity, and particle size. These computer-aided approaches allow for simultaneous optimization of multiple formulation parameters and provide a way to shorten product development time compared to traditional trial-and-error methods.
This document provides an overview of population modelling as used in drug development. It discusses:
- The history and introduction of population modelling in 1972 to integrate data and aid drug development decisions.
- The types of models used, including PK, PKPD, disease progression, and meta-models.
- The components of population models, which include structural models describing response over time, stochastic models of variability, and covariate models of influencing factors.
- The concepts of model parameter estimation from data and model simulation to generate new data for evaluation and inference.
Targeting methods introduction preparation and evaluation: NanoParticles & Li...SURYAKANTVERMA2
This document provides information on molecular pharmaceutics and targeting methods, including nanoparticles and liposomes. It discusses various targeting strategies such as passive, active, inverse and ligand-mediated targeting. Nanoparticles and liposomes are described as carrier systems for targeted drug delivery. The key preparation techniques for nanoparticles include solvent evaporation, double emulsification, emulsions-diffusion and nano precipitation. Nanoparticles are evaluated based on parameters like yield, drug content, particle size, shape, zeta potential and thermal analysis. Targeted drug delivery aims to increase drug concentration at disease sites and reduce side effects.
Niosomes, Aquasomes, Phytosomes, and Electrosomes are novel drug delivery systems. Niosomes are vesicles composed of non-ionic surfactants that can encapsulate medications and offer transdermal delivery benefits. Aquasomes are three-layered nanoparticles containing a ceramic core, carbohydrate coating, and adsorbed bioactive molecules. Phytosomes contain phytoconstituents bound to phospholipids to improve absorption of plant-based compounds. Electrosomes are ion channel proteins that span cell membranes and control ion flux, enabling electrical signaling in tissues like the brain, muscles and nervous system.
computer aided formulation developmentSUJITHA MARY
The document discusses optimization techniques used in computer aided formulation development. It defines optimization as choosing the best alternative while considering all influencing factors. Optimization techniques help minimize experimental trials, reduce costs and save time compared to traditional trial and error methods. The document describes various experimental design approaches like factorial designs, response surface methodology and mixture designs that are used to optimize formulations. It also discusses simultaneous techniques like evolutionary operations and simplex method as well as sequential techniques like mathematical modeling and search methods. Optimization is important for developing formulations with desired performance and ensuring reproducible, large-scale manufacturing.
Cellular uptake of drugs can occur through passive diffusion of small molecules or active transport of larger particles via endocytosis, exocytosis, phagocytosis, or pinocytosis. Transport across epithelial barriers relies on passive diffusion, carriers, or endocytosis. Extravasation from blood vessels depends on permeability and physicochemical drug properties, while lymphatic uptake drains drug molecules from tissues. The reticuloendothelial system phagocytoses pathogens and debris from circulation and tissues.
NIOSOMES , GENERAL CHARACTERISTICS OF NIOSOME , TYPES OF NIOSOMES , OTHERS TYPES OF NIOSOMES , NIOSOMES VS LIPOSOMES , COMPONENTS OF NIOSOMES , Non-ionic surfactant , Cholesterol , Charge inducing molecule , METHOD OF PREPARATION , preparation of small unilamellar vesicles , Sonication , Micro fluidization , preparation of large unilamellar vesicles , Reverse Phase Evaporation , Ether Injection , preparation of Multilamellar vesicles , Hand shaking method , Trans membrane pH gradient drug uptake process (remote loading) , Miscellaneous method :Multiple membrane extrusion method , The “Bubble” Method , Formation of Niosomes From Proniosomes , SEPARATION OF UNENTRAPPED DRUGS , Gel Filtration , Dialysis , Centrifugation , FACTORS AFFECTING THE PHYSICOCHEMICAL PROPERTIES OF NIOSOMES , Membrane Additives , Temperature of Hydration , PROPERTIES OF DRUGS , AMOUNT AND TYPE OF SURFACTANT
Structure of Surfactants , Resistance to Osmotic Stress , Characterization of niosomes ,Therapeutic applications of Niosomes , For Controlled Release of Drugs , To Improve the Stability and Physical Properties of the Drugs , For Targeting and Retention of Drug in Blood Circulation , Proniosomes , Aspasomes , Vesicles in Water and Oil System (v/w/o) ,Bola - niosomes , Discomes , Deformable niosomes or elastic niosomes , According to the nature of lamellarity ,Small Unilamellar vesicles (SUV) 25 – 500 nm in size.,Large Unilamellar vesicles (LUV) 0.1 – 1μm in size , Multilamellar vesicles (MLV) 1-5 μm in size , According to the size:Small Niosomes (100 nm – 200 nm) , Large Niosomes (800 nm – 900 nm),Big Niosomes (2 μm – 4 μm)
This document discusses the use of computers in pharmaceutical formulation. It begins with an introduction to pharmaceutical formulation and design of experiment techniques. It then provides examples of emulsion and microemulsion formulations. The document reviews several software programs used for design of experiment and optimization in formulation development. It also discusses using design of experiment techniques for screening critical factors and developing different dosage forms. Finally, it covers legal protection of innovative computer uses in research and development, including patents, copyright, database protection, and trade secrets.
This document discusses various approaches for delivering drugs to the brain by bypassing the blood-brain barrier (BBB). It describes invasive approaches like convection-enhanced delivery which involves inserting a catheter into the brain. It also discusses pharmacological, physiological, and prodrug approaches. Various carrier systems are covered like liposomes, nanoparticles, monoclonal antibodies, and colloidal carriers. The mechanisms of transport through the BBB like endocytosis, receptor-mediated transcytosis, and adsorption are also summarized. Overall, the document provides a comprehensive overview of the challenges of brain drug delivery and different strategies researchers are exploring to enhance transport of therapeutics across the BBB.
This document discusses microencapsulation in pharmacy. It defines microencapsulation as enclosing solids, liquids, or gases in microscopic particles by forming thin coatings around them. Reasons for microencapsulation include isolation, controlled release, and masking tastes/odors. Key considerations in microencapsulation are the core and coating materials, as well as the encapsulation method used. Common methods described are coacervation, spray drying, pan coating, solvent evaporation, and extrusion. The document outlines various polymers, core materials, and mechanisms that can be used for microencapsulation and controlled drug delivery.
This document provides an overview of microencapsulation. It defines microencapsulation as enclosing solids, liquids, or gases in microscopic particles using thin coatings. Reasons for microencapsulation include controlled release of drugs or masking tastes/odors. Key considerations are the core and coating materials and their stability/release characteristics. Common methods include coacervation, pan coating, spray drying, and solvent evaporation. Microencapsulation has applications in pharmaceuticals, food, and other industries.
hisory of computers in pharmaceutical research presentation.pptxDhanaa Dhoni
Computers have been used in pharmaceutical research and development since the 1940s. Early computers were large mainframe systems that were expensive and shared between organizations. By the 1960s, some pharmaceutical companies had acquired early computers like the IBM 650 to assist with scientific tasks. Today, computers are essential for tasks across the pharmaceutical industry from drug design and clinical trials to manufacturing, sales, and more. Advanced statistical modeling and software continue to be important tools in pharmaceutical research and development.
The document discusses various drug delivery systems including niosomes, aquasomes, and phytosomes. Niosomes are vesicles composed of non-ionic surfactants that can encapsulate medications and offer advantages over liposomes such as lower cost and greater stability. Aquasomes are three-layered nanoparticle structures consisting of a ceramic core coated with an oligosaccharide film that can deliver fragile molecules while maintaining their integrity. Phytosomes utilize phospholipids to surround active herbal constituents, improving their absorption and bioavailability compared to traditional herbal extracts.
computer in pharmaceutical formulation of microemlastionsurya singh
This document discusses the use of computer-aided techniques in the development of microemulsion drug carriers, with a special emphasis on optimization. It describes how artificial neural networks (ANN) can be used as tools to accurately predict the microemulsion area based on formulation composition. Various optimization techniques are explored, including factorial designs, response surface methodology, and the use of ANN for multi-objective optimization problems. Microemulsions offer benefits as drug carriers, and optimization is important to develop formulations that solubilize both water-soluble and oil-soluble compounds for delivery.
Intranasal drug delivery system - Introduction, Nasal enzymes and nasal ph, cross sectional view of nose, factors affecting nasal absorption, general formulations of intranasal drugs, Intranasal dosage forms, nasal sprays, spray pump devices, nasal aerosols, compressed air nebulizers, nasal powder, nasal gels, applications of intranasal drug delivery system, delivery of intranasal vaccines, intranasal anaesthesia, Evaluation of intranasal formulation, ussing chamber, Advantages and disadvantages of intranasal drug delivery system
This document discusses tumour targeting for drug delivery. It begins with an introduction defining different types of tumours and the differences between normal and cancer cells. It then discusses the stages of tumour development and approaches to tumour targeting, including passive targeting via the enhanced permeability and retention effect, active targeting using ligands against tumour cell receptors, and triggered drug delivery responsive to the tumour microenvironment. Examples of approved drugs using different carriers for passive targeting are also provided.
This document discusses targeted drug delivery systems. It begins by defining targeted drug delivery as selectively delivering medication only to its site of action to increase concentration there and reduce it elsewhere. This improves efficacy and reduces side effects. It then lists the ideal characteristics of targeted systems and the advantages they provide like reduced toxicity and dosage. The document outlines various carrier systems and the biological processes involved in cellular uptake, transport across barriers, extravasation into tissues, and lymphatic uptake. It concludes by describing different strategies for targeted delivery, including passive, active, and physical targeting approaches.
This document discusses descriptive versus mechanistic modeling approaches in drug discovery. It provides examples of descriptive modeling, which aims to describe data patterns without understanding the underlying mechanisms, and mechanistic modeling, which works with domain experts to translate scientific knowledge into mathematical representations of the data-generating processes. The document presents tumor growth curve analysis as an example where mechanistic models like Richards and Gompertz curves can incorporate understandings of competing catabolic and anabolic processes to better capture the fundamental characteristics of growth.
This document discusses the application of computer-aided techniques in developing pharmaceutical emulsions and microemulsions. It provides several examples of how experimental design and artificial neural networks have been used to optimize emulsion formulations and processing parameters. Specifically, researchers have used factorial design, response surface methodology, and artificial neural networks to determine the ideal concentrations of formulation components, processing conditions, and emulsifier mixtures to produce emulsions with desirable properties like stability, viscosity, and particle size. These computer-aided approaches allow for simultaneous optimization of multiple formulation parameters and provide a way to shorten product development time compared to traditional trial-and-error methods.
This document provides an overview of population modelling as used in drug development. It discusses:
- The history and introduction of population modelling in 1972 to integrate data and aid drug development decisions.
- The types of models used, including PK, PKPD, disease progression, and meta-models.
- The components of population models, which include structural models describing response over time, stochastic models of variability, and covariate models of influencing factors.
- The concepts of model parameter estimation from data and model simulation to generate new data for evaluation and inference.
Targeting methods introduction preparation and evaluation: NanoParticles & Li...SURYAKANTVERMA2
This document provides information on molecular pharmaceutics and targeting methods, including nanoparticles and liposomes. It discusses various targeting strategies such as passive, active, inverse and ligand-mediated targeting. Nanoparticles and liposomes are described as carrier systems for targeted drug delivery. The key preparation techniques for nanoparticles include solvent evaporation, double emulsification, emulsions-diffusion and nano precipitation. Nanoparticles are evaluated based on parameters like yield, drug content, particle size, shape, zeta potential and thermal analysis. Targeted drug delivery aims to increase drug concentration at disease sites and reduce side effects.
Niosomes, Aquasomes, Phytosomes, and Electrosomes are novel drug delivery systems. Niosomes are vesicles composed of non-ionic surfactants that can encapsulate medications and offer transdermal delivery benefits. Aquasomes are three-layered nanoparticles containing a ceramic core, carbohydrate coating, and adsorbed bioactive molecules. Phytosomes contain phytoconstituents bound to phospholipids to improve absorption of plant-based compounds. Electrosomes are ion channel proteins that span cell membranes and control ion flux, enabling electrical signaling in tissues like the brain, muscles and nervous system.
computer aided formulation developmentSUJITHA MARY
The document discusses optimization techniques used in computer aided formulation development. It defines optimization as choosing the best alternative while considering all influencing factors. Optimization techniques help minimize experimental trials, reduce costs and save time compared to traditional trial and error methods. The document describes various experimental design approaches like factorial designs, response surface methodology and mixture designs that are used to optimize formulations. It also discusses simultaneous techniques like evolutionary operations and simplex method as well as sequential techniques like mathematical modeling and search methods. Optimization is important for developing formulations with desired performance and ensuring reproducible, large-scale manufacturing.
Cellular uptake of drugs can occur through passive diffusion of small molecules or active transport of larger particles via endocytosis, exocytosis, phagocytosis, or pinocytosis. Transport across epithelial barriers relies on passive diffusion, carriers, or endocytosis. Extravasation from blood vessels depends on permeability and physicochemical drug properties, while lymphatic uptake drains drug molecules from tissues. The reticuloendothelial system phagocytoses pathogens and debris from circulation and tissues.
NIOSOMES , GENERAL CHARACTERISTICS OF NIOSOME , TYPES OF NIOSOMES , OTHERS TYPES OF NIOSOMES , NIOSOMES VS LIPOSOMES , COMPONENTS OF NIOSOMES , Non-ionic surfactant , Cholesterol , Charge inducing molecule , METHOD OF PREPARATION , preparation of small unilamellar vesicles , Sonication , Micro fluidization , preparation of large unilamellar vesicles , Reverse Phase Evaporation , Ether Injection , preparation of Multilamellar vesicles , Hand shaking method , Trans membrane pH gradient drug uptake process (remote loading) , Miscellaneous method :Multiple membrane extrusion method , The “Bubble” Method , Formation of Niosomes From Proniosomes , SEPARATION OF UNENTRAPPED DRUGS , Gel Filtration , Dialysis , Centrifugation , FACTORS AFFECTING THE PHYSICOCHEMICAL PROPERTIES OF NIOSOMES , Membrane Additives , Temperature of Hydration , PROPERTIES OF DRUGS , AMOUNT AND TYPE OF SURFACTANT
Structure of Surfactants , Resistance to Osmotic Stress , Characterization of niosomes ,Therapeutic applications of Niosomes , For Controlled Release of Drugs , To Improve the Stability and Physical Properties of the Drugs , For Targeting and Retention of Drug in Blood Circulation , Proniosomes , Aspasomes , Vesicles in Water and Oil System (v/w/o) ,Bola - niosomes , Discomes , Deformable niosomes or elastic niosomes , According to the nature of lamellarity ,Small Unilamellar vesicles (SUV) 25 – 500 nm in size.,Large Unilamellar vesicles (LUV) 0.1 – 1μm in size , Multilamellar vesicles (MLV) 1-5 μm in size , According to the size:Small Niosomes (100 nm – 200 nm) , Large Niosomes (800 nm – 900 nm),Big Niosomes (2 μm – 4 μm)
This document discusses the use of computers in pharmaceutical formulation. It begins with an introduction to pharmaceutical formulation and design of experiment techniques. It then provides examples of emulsion and microemulsion formulations. The document reviews several software programs used for design of experiment and optimization in formulation development. It also discusses using design of experiment techniques for screening critical factors and developing different dosage forms. Finally, it covers legal protection of innovative computer uses in research and development, including patents, copyright, database protection, and trade secrets.
This document discusses various approaches for delivering drugs to the brain by bypassing the blood-brain barrier (BBB). It describes invasive approaches like convection-enhanced delivery which involves inserting a catheter into the brain. It also discusses pharmacological, physiological, and prodrug approaches. Various carrier systems are covered like liposomes, nanoparticles, monoclonal antibodies, and colloidal carriers. The mechanisms of transport through the BBB like endocytosis, receptor-mediated transcytosis, and adsorption are also summarized. Overall, the document provides a comprehensive overview of the challenges of brain drug delivery and different strategies researchers are exploring to enhance transport of therapeutics across the BBB.
This document discusses microencapsulation in pharmacy. It defines microencapsulation as enclosing solids, liquids, or gases in microscopic particles by forming thin coatings around them. Reasons for microencapsulation include isolation, controlled release, and masking tastes/odors. Key considerations in microencapsulation are the core and coating materials, as well as the encapsulation method used. Common methods described are coacervation, spray drying, pan coating, solvent evaporation, and extrusion. The document outlines various polymers, core materials, and mechanisms that can be used for microencapsulation and controlled drug delivery.
This document provides an overview of microencapsulation. It defines microencapsulation as enclosing solids, liquids, or gases in microscopic particles using thin coatings. Reasons for microencapsulation include controlled release of drugs or masking tastes/odors. Key considerations are the core and coating materials and their stability/release characteristics. Common methods include coacervation, pan coating, spray drying, and solvent evaporation. Microencapsulation has applications in pharmaceuticals, food, and other industries.
Micro-encapsulation involves enclosing solids, liquids, or gases within microscopic particles coated with thin walls. It allows for controlled release of substances like drugs. Various methods are used including air suspension, coacervation, and spray drying. Coacervation involves separating a coating material from solution to form liquid droplets that coat core materials. This process protects substances and allows targeted, timed delivery for applications like pharmaceuticals.
Micro-encapsulation involves enclosing solids, liquids, or gases in microscopic particles coated with thin walls. It is used for controlled drug delivery, masking tastes/odors, and isolating reactive materials. Common methods include coacervation, spray drying, fluidized bed coating, and polymerization. Micro-encapsulation can provide benefits like controlled release, reduced toxicity, and improved handling of materials.
microencapsulation is the part of an pharmaceutics, in that the method of preperation is giving. and all related thing about microencapsulation is given.
thanks you.
This document provides an overview of microencapsulation including its advantages, applications, materials used, techniques, kinetics, and evaluation. Microencapsulation coats small particles or droplets of active ingredients with polymeric films. It has benefits like sustained drug release, masking tastes/odors, and stabilizing compounds. Common coating materials are water soluble/insoluble resins, waxes, and lipids. Major techniques include coacervation, spray drying, pan coating, and solvent evaporation. Drug release occurs via diffusion, dissolution, osmosis, or erosion. Microcapsules are evaluated based on characterization, morphology, kinetics and in vitro drug release.
Microencapsulation is the process of coating solid or liquid materials in a polymeric film. It has advantages like sustained drug release, masking taste/odor, and protecting unstable drugs. Common coating materials are water soluble/insoluble resins, waxes, and lipids. Microencapsulation techniques include air suspension, coacervation, spray drying, pan coating, solvent evaporation, and polymerization. The drug release kinetics depend on factors like coating thickness, porosity and permeability. Microcapsules are evaluated for characteristics, morphology, viscosity, density and in vitro drug release.
Microencapsulation involves coating solid, liquid, or gaseous active ingredients within thin polymeric coatings to produce microcapsules 1-1000 microns in size. It offers several advantages including protecting active ingredients, controlling release rates, and masking tastes/odors. Common techniques include solvent evaporation, pan coating, spray drying, and polymerization. Coacervation involves separating a hydrocolloid coating from solution and depositing it around active ingredient droplets. Microencapsulation has applications in food, pharmaceuticals, and other industries by improving product shelf life, stability and delivery properties.
The document discusses different methods of microencapsulation including air suspension, coacervation, multiorifice centrifugal process, spray drying, and pan coating. It provides details on the working mechanisms and variables that affect each process. Microencapsulation can be used to encapsulate solids, liquids, or gases to properties such as shelf life, taste, and controlled release profiles.
This document provides an overview of microencapsulation including its classification, fundamental considerations, morphology, coating materials, reasons for use, release mechanisms, techniques, evaluation, applications, and disadvantages. Microencapsulation involves enclosing solids, liquids, or gases in microscopic particles with thin coatings to form microparticles, microcapsules, or microspheres ranging from 100-5000 microns. It allows for controlled release, masking of tastes, and protection of unstable or volatile materials. Common techniques include coacervation, pan coating, spray drying, solvent evaporation, and polymerization.
Microencapsulation involves coating tiny particles or droplets of active ingredients with a thin polymeric film. There are two main types: microcapsules, which have a reservoir structure, and microspheres, which have a matrix structure. Various methods can be used for microencapsulation including pan coating, spray drying, solvent evaporation, coacervation, and centrifugal extrusion. The choice of coating material and method depends on the properties of the core ingredient and desired release characteristics. Microencapsulation provides benefits such as masking tastes, sustained release of ingredients, and protection from moisture, oxygen, and light.
Ndds 4 MICROENCAPSULATION DRUG DELIVERY SYSTEMshashankc10
This document discusses microencapsulation, which involves coating solid, liquid, or gas core materials in microscopic capsules. It defines microencapsulation and describes the core and coating materials. Common microencapsulation techniques include air suspension, coacervation, spray drying, pan coating, solvent evaporation, and emulsion methods. The techniques produce microparticles or microcapsules ranging from 1-1000 microns. Microencapsulation offers benefits like masking tastes, sustaining drug release, and protecting unstable core materials.
The document discusses microencapsulation and microcapsules. It defines microencapsulation as the process of coating solid or liquid core materials on a very small scale, usually 1-1000 microns in size. The core materials can be drugs, flavors, or fragrances. The coating materials are typically polymers that act as shells to provide controlled release or stabilization. Several microencapsulation methods are described in detail, including pan coating, solvent evaporation, phase separation, spray drying, and polymerization. The mechanisms of drug release from microcapsules and some applications of microencapsulation technology are also summarized.
Microencapsulation is a process of coating solid or liquid active ingredients within inert polymeric materials to form microparticles or microcapsules between 3-800μm in diameter. There are various techniques for microencapsulation including air suspension, coacervation, spray drying, solvent evaporation, and polymerization. Microencapsulation can be used to increase bioavailability, alter drug release profiles, improve patient compliance, produce targeted drug delivery, and mask unpleasant tastes. Evaluation of the microcapsules involves determining yield percentage, particle size analysis, encapsulation efficiency, drug content, and drug release studies.
Microencapsulation is a process that coats solid or liquid active ingredients with polymers to form microparticles or microcapsules between 3-800μm in diameter. It can be used to increase bioavailability, control drug release, improve compliance, and enable targeted delivery. Common techniques include spray drying, pan coating, polymerization, and emulsion methods. Microcapsules have a core surrounded by a coating, while microspheres have the active ingredient dispersed throughout the polymer. Microencapsulation offers benefits like controlled release, taste masking, and protecting unstable ingredients.
The document provides information on microencapsulation. It discusses the core and coating materials used, advantages and disadvantages of microencapsulation, and various methods for microencapsulation preparation including air suspension, coacervation, multi-orifice centrifugal process, and solvent evaporation techniques. The fundamental considerations for microencapsulation and evaluation of microcapsules are also covered.
unit 2. various approaches on Microencapsulation.pdfAkankshaPatel55
Microencapsulation is a process of coating tiny particles or droplets with a thin layer of material to create small capsules. These capsules, called microcapsules, can range in size from a few nanometers to a few millimeters and can be made from a variety of materials, such as polymers, lipids, and carbohydrates.
The core material of a microcapsule can be a solid, liquid, or gas. Some common core materials include:
Food ingredients: Vitamins, flavors, colors, antioxidants
Pharmaceuticals: Drugs, diagnostic agents
Agrochemicals: Pesticides, fertilizers, herbicides
Cosmetics: Fragrances, sunscreens, moisturizers
Electronics: Conductive materials, lubricants
The shell of a microcapsule is designed to protect the core material from the environment and to control its release. The release of the core material can be triggered by a variety of factors, such as:
Temperature
pH
Enzymes
Ultrasound
Applications in various industries, including:
Food industry: it is used to protect food ingredients from degradation, such as vitamins and flavors. It can also be used to control the release of flavors and colors, creating novel food experiences.
Pharmaceutical industry: used to improve the delivery of drugs by protecting them from the stomach environment and targeting them to specific sites in the body.
Agrochemical industry: used to protect agrochemicals from degradation and to control their release, reducing the amount of chemicals needed and minimizing environmental impact.
Cosmetic industry: used to protect cosmetic ingredients from degradation and to control their release, creating long-lasting products.
Electronics industry: used to protect electronic components from corrosion and to control the release of lubricants.
TECHNIQUES
Physicochemical techniques:
Coacervation: Involves layering oppositely charged polymers around the core material, forming a shell through electrostatic interaction.
Interfacial polymerization Utilizes monomers that react at the interface between the core and an immiscible phase, generating a polymer shell.
In situ polymerization: Monomers are directly polymerized around the core material within a continuous phase, creating the shell.
Spray drying: Emulsified or suspended core material is atomized and dried in a hot air stream, forming microcapsules as the solvent evaporates.
Fluidized bed coating: Core material is fluidized in a heated chamber while coating solution is sprayed, forming a layer-by-layer shell.
Physico-mechanical techniques:
Pan coating: Similar to sugar-coating, core material is layered with coating material in a rotating pan, building the shell gradually.
Extrusion: Molten core and coating materials are co-extruded to form capsules with con concentric layers.
Encapsulation by solvent evaporation: Core material is dissolved in a solvent, then dispersed in a non-solvent, causing precipitation and shell formation.
Other techniques:
Electrostatic encapsulation,
Microfluidic encapsulation.
This document discusses microcapsules and microspheres, including their types, sizes, materials used, and preparation methods. Microcapsules contain an active agent surrounded by a polymeric shell, while microspheres are small spherical particles made of polymers, glass, or ceramics between 1-1000 microns in diameter. Common preparation methods include emulsion polymerization, interfacial polycondensation, suspension crosslinking, solvent evaporation/extraction, and coacervation/phase separation.
Microencapsulation is a process where core materials are surrounded by a coating to form microparticles or microcapsules between 3-800μm in size. There are various techniques to produce microcapsules including air suspension, solvent evaporation, spray drying, pan coating, and polymerization. Microencapsulation can be used to increase bioavailability, alter drug release profiles, improve patient compliance, produce targeted drug delivery, and protect core materials. Some example applications are improving stability, reducing volatility, avoiding incompatibilities, and masking tastes.
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3. INTRODUCTION
Definition :
Microencapsulation is a process by which solids, liquids or
even gases may be enclosed in microscopic particles by
formation of thin coatings of wall material around the
substances.
3
5. A well designed controlled drug delivery system
- can overcome some of the problems of conventional therapy.
- enhance the therapeutic efficacy of a given drug.
5
6. To obtain maximum therapeutic efficacy, drug is to be
delivered :
-to the target tissue
-in the optimal amount
-in the right period of time
there by causing little toxicity and minimal side effects.
6
7. One such approach is using microspheres as carriers for drugs.
Microspheres are characteristically free flowing powders
consisting of proteins or synthetic polymers
biodegradable in nature
particle size less than 200 μm.
7
10. REASONS FOR MICROENCAPSULATION
10
Isolation of core from its surroundings,
as in isolating vitamins from the deteriorating effects of oxygen.
retarding evaporation of a volatile core.
improving the handling properties of a sticky material.
11. isolating a reactive core from chemical attack.
for controlled release of drugs.
masking the taste or odor of the core.
for safe handling of the toxic materials.
to get targeted release of the drug,
11
12. FUNDAMENTAL CONSIDERATIONS
12
nature of the core and coating materials.
the stability and release characteristics of the coated materials.
the microencapsulation methods.
13. CORE MATERIAL
The core material is defined as the specific material to be
coated.
The core material can be in liquid or solid in nature.
The composition of the core material can be varied
-as the liquid core can include dispersed and/or dissolved
material.
. 14
14. The solid core can be single solid substance or mixture of
active constituents, stabilizers, diluents, excipients and release-
rate retardants or accelerators.
14
15. COATING MATERIAL
15
The selection of coating material decides the physical and
chemical properties of the resultant microcapsules/microspheres.
While selecting a polymer the product requirements should be
taken into consideration are:
- stabilization
- reduced volatility
- release characteristics
- environmental conditions, etc.
17. The polymer should be capable of forming a film that is
cohesive with the core material.
17
It should be chemically compatible, non-reactive with the
core material.
It should provide the desired coating properties such as:
- strength
-flexibility,
-impermeability,
-optical properties and stability.
18. Generally hydrophilic / hydrophobic polymers /a combination
of both are used for the microencapsulation process.
A number of coating materials have been used successfully
examples :
-Gelatin
- polyvinyl alcohol
- ethyl cellulose
-cellulose acetate phthalate etc. 18
19. The film thickness can be varied considerably depending
on:
-the surface area of the material to be coated
-Other physical characteristics of the system.
The microcapsules may consist of a single particle or
clusters of particles.
19
20. After isolation from the liquid manufacturing vehicle
and drying, the material appears as a free flowing powder.
The powder is suitable for formulation as:
-compressed tablets
-hard gelatin capsules
-suspensions and other dosage forms.
20
21. Morphology of Microcapsules
21
The morphology of microcapsules depends mainly on the core
material and the deposition process of the shell.
1Mononuclear (core-shell) microcapsules contain the shell around
the core.
2Polynuclear capsules have many cores enclosed within the shell.
3- Matrix encapsulation in which the core material is distributed
homogeneously into the shell material.
- In addition to these three basic morphologies, microcapsules can
also be mononuclear with multiple shells, or they may form clusters
of
microcapsules.
23. RELEASE MECHANISMS
23
Even when the aim of a microencapsulation application is
the isolation of the core from its surrounding, the wall must
be ruptured at the time of use.
A variety of release mechanisms have been proposed for
microcapsules :
24. by pressure or shear stress.
24
by melting the wall.
by dissolving it under particular conditions, as in the case of
an enteric drug coating.
25. by solvent action
by enzyme attack
by chemical reaction
by hydrolysis or slow disintegration.
25
26. METHODS OF PREPARATION
26
Preparation of microspheres should satisfy certain
criteria:
The ability to incorporate reasonably high concentrations of
the drug.
Stability of the preparation after synthesis with a clinically
acceptable shelf life.
27. Controlled particle size and dispersability in aqueous
vehicles for injection.
Release of active reagent with a good control over a wide
time scale.
Biocompatibility with a controllable biodegradability.
Susceptibility to chemical modification.
27
28. MICROENCAPSULATION METHODS
28
Air suspension
Coacervation phase separation
Multiorifice-centrifugal process
Spray drying and congealing
Pan coating
33. AIR SUSPENSION:
33
solid, particulate core materials are dispersed in a supporting
air stream.
The coating material is sprayed on the air suspended
particles.
Within the coating chamber, particles are suspended on an
upward moving air stream.
34. The design of the chamber and its operating parameters
effect a recirculating flow of the particles through the coating
zone portion of the chamber, where a coating material, usually
a polymer solution, is spray applied to the moving particles.
During each pass through the coating zone, the core material
receives an increment of coating material.
34
37. The cyclic process is repeated, perhaps several hundred times
during processing, depending on:
-the purpose of microencapsulation
-the coating thickness desired
-Until the core material particles are thoroughly encapsulated.
The supporting air stream also serves to dry the product while it
is being encapsulated.
37
38. Schematics of a fluid-bed coater.
(a) Top spray;
(b) bottom spray;
(c) tangential spray
38
39. Drying rates are directly related to the volume temperature of
the supporting air stream.
39
41. The term originated from the Latin ›acervus‹ , meaning
“heap”.
This was the first reported process to be adapted for the
industrial production of microcapsules.
Currently, two methods for coacervation are available, namely
simple and complex processes.
41
42. The mechanism of microcapsule formation for both
processes is identical, except for the way in which the phase
separation is carried out.
In simple coacervation a desolvation agent is added for
phase
separation, whereas complex coacervation involves
complexation between two oppositely charged polymers.
42
43. The process consists of three steps:
Formation of three immiscible phases;
solvent.
a core material phase.
a coating material phase.
Deposition of the coating material on the core
material.
Rigidizing the coating usually by thermal, cross linking or
desolvation techniques to form a microcapsule. 44
44. The core material is dispersed in a solution of the coating
polymer.
The coating material phase, an immiscible polymer in liquid
state is formed by
(i) changing temperature of polymer solution
(ii) addition of salt,
e.g. addition of sodium sulphate solution to gelatine solution in
vitamin encapsulation ,
44
45. (iii) addition of nonsolvent, e.g. addition of isopropyl ether to
methyl ethyl ketone solution of cellulose acetate butyrate
(methylscopalamine hydrobromide is core),
(iv)addition of incompatible polymer to the polymer solution, e.g.
addition of polybutadiene to the solution of ethylcellulose in
toluene (methylene blue as core material),
(v)inducing polymer – polymer interaction, e.g. interaction of
gum Arabic and gelatine at their iso-electric point.
45
46. Second step, includes deposition of liquid polymer upon the
core material.
Finally, the prepared microcapsules are stabilized by
crosslinking, desolvation or thermal treatment.
Crosslinking is the formation of chemical links between
molecular chains to form a three-dimensional network of
connected molecules.
46
47. The vulcanization of rubber using elemental sulfur is an
example of crosslinking, converting raw rubber from a weak
plastic to a highly resilient elastomer.
Chitosan served as an effective cross-linker at pH 7.0, while
polyethylenimine (PEI) was used as cross-linker under basic
conditions (pH 10.5).
47
48. Schematic representation of the coacervation process.
(a) Core material dispersion in solution of shell polymer;
(b) separation of coacervate from solution;
(c) coating of core material by microdroplets of coacervate;
(d) coalescence of coacervate to form continuous shell around core particles.
48
50. Polymer Encapsulation by Rapid Expansion of Supercritical Fluids
50
Supercritical fluids are highly compressed gasses that possess
several advantageous properties of both liquids and gases.
The most widely used being supercritical carbon dioxide(CO2),
alkanes (C2to C4), and nitrous oxide (N2O).
A small change in temperature or pressure causes a large change
in the density of supercritical fluids near the critical point.
51. Supercritical CO2 is widely used because of following
advantages:
-its low critical temperature value,
-nontoxic,
-non flammable properties;
-readily available,
-highly pure
-cost-effective.
51
52. The most widely used methods are as follows:
•Rapid expansion of supercritical solution (RESS)
•Gas anti-solvent (GAS)
•Particles from gas-saturated solution (PGSS)
52
53. Rapid expansion of supercritical solution
53
Supercritical fluid containing the active ingredient and the
shell material are maintained at high pressure and then
released at atmospheric pressure through a small nozzle.
The sudden drop in pressure causes desolvation of the shell
material, which is then deposited around the active ingredient
(core) and forms a coating layer.
54. The disadvantage of this process is that both the active
ingredient and the shell material must be very soluble in
supercritical fluids.
In general, very few polymers with low cohesive energy
densities (e.g., polydimethylsiloxanes, polymethacrylates) are
soluble in supercritical fluids such as CO2.
54
55. The solubility of polymers can be enhanced by using
co-solvents.
In some cases nonsolvents are used; this increases the solubility
in supercritical fluids, but the shell materials do not dissolve at
atmospheric pressure.
55
57. Gas anti-solvent (GAS) process
57
This process is also called supercritical fluid anti-solvent (SAS).
Supercritical fluid is added to a solution of shell material and the
active ingredients and maintained at high pressure.
This leads to a volume expansion of the solution that causes
super saturation such that precipitation of the solute occurs.
The solute must be soluble in the liquid solvent, but should not
dissolve in the mixture of solvent and supercritical fluid.
58. Particles from a gas-saturated solution (PGSS)
58
This process is carried out by mixing core and shell materials
in supercritical fluid at high pressure.
During this process supercritical fluid penetrates the shell
material, causing swelling.
When the mixture is heated above the glass transition
temperature (Tg), the polymer liquefies.
59. Upon releasing the pressure, the shell material is allowed to
deposit onto the active ingredient.
In this process, the core and shell materials may not be soluble
in
the supercritical fluid.
59
60. The liquid solvent must be miscible with the supercritical
fluid.
This process is unsuitable for the encapsulation of water-
soluble ingredients as water has low solubility in
supercritical fluids.
It is also possible to produce submicron particles using
this method.
60
61. MULTIORIFICE-CENTRIFUGAL PROCESS
61
The Southwest Research Institute (SWRI) has developed this
method.
It is a mechanical process for producing microcapsules.
centrifugal forces are used to hurl a core material particle through
an enveloping microencapsulation membrane.
62. Processing variables include:
the rotational speed of the cylinder,
the flow rate of the core and coating materials,
the concentration, viscosity, surface tension of the core
material.
62
63. The multiorifice-centrifugal process is capable for
microencapsulating liquids and solids of varied size ranges,
with diverse coating materials.
The encapsulated product can be supplied as
- slurry in the hardening media
- dry powder.
Production rates of 50 to 75 pounds per hour.
63
64. PAN COATING
64
suitable for relatively large particles.
solid particles greater than 600 microns in size are generally
coated by pan coating.
extensively employed for the Preparation of controlled
release beads.
65. Medicaments are usually coated onto various spherical
substrates such as sugar seeds and the coated with
protective layers of various polymers.
65
The coating is applied as a solution or as an atomized
spray to the desired solid core material in the coating pan.
66. Usually, to remove the coating solvent, warm air is passed
over the coated materials as the coatings are being applied in
the coating pans.
In some cases, final solvent removal is accomplished in
drying oven.
66
69. CO EXTRUSION
69
1A dual fluid stream of liquid core and
shell materials is
pumped through concentric tubes and
forms droplets
under the influence of vibration.
2The shell is then hardened by chemical
cross linkings,
cooling, or solvent evaporation.
- Different types of extrusion nozzles have
been
developed in order to optimize the process
72. SPRAY DRYING AND SPRAY
CONGEALING
72
both process involve
-Dispersing the core material in a liquefied coating
Substance /spraying or introducing the coating mixture on to core
material.
-solidification of coating material
The principal difference between the two methods, is the means
by which coating solidification is accomplished.
73. Coating solidification in spray drying is effected by rapid
evaporation of a solvent in which the coating material is
dissolved.
Coating solidification in spray congealing method is
accomplished by
-thermally congealing a molten coating material or
-by solidifying a dissolved coating by introducing the coating
core material mixture into a nonsolvent.
73
74. Removal of the nonsolvent or solvent from the coated
product is then accomplished by sorption extraction or
evaporation techniques.
74
75. Microencapsulation by spray-drying is a low-cost commercial
process.
Mostly used for the encapsulation of fragrances, oils and flavours.
Core particles are dispersed in a polymer solution and sprayed into
a hot chamber.
The shell material solidifies onto the core particles as the solvent
evaporates such that the microcapsules obtained are of polynuclear
or matrix type.
75
76. Chitosan microspheres cross-linked with three different cross-
linking agents viz,
-tripolyphosphate (TPP),
-formaldehyde (FA)
-gluteraldehyde (GA) have been prepared by spray drying
technique.
The influence of these cross-linking agents on the properties of
spray dried chitosan microspheres was extensively investigated.
76
77. The particle size and encapsulation efficiencies of thus
prepared chitosan microspheres ranged mainly between 4.1–
4.7µm and 95.12–99.17%, respectively.
Surface morphology, % erosion, % water uptake and drug
release properties of the spray dried chitosan microspheres was
remarkably influenced by the type (chemical or ionic) and
extent (1 or 2%w/w) of cross-linking agents.
77
78. Spray dried chitosan microspheres cross-linked with TPP
exhibited
higher swelling capacity, % water uptake, % erosion and drug release
rate at both the cross-linking extent (1 and 2%w/w) when compared
to those cross-linked with FA and GA.
The sphericity and surface smoothness of the spray dried chitosan
microspheres was lost when the cross-linking extent was increased
from 1 to 2%w/w.
78
79. Release rate of the drug from spray dried chitosan
microspheres decreased when the cross-linking extent was
increased from 1 to 2%w/w.
The physical state of the drug in chitosan-TPP, chitosan-FA
and chitosan-GA matrices was confirmed by the X-ray
diffraction (XRD) study and found that the drug remains in a
crystalline state even after its encapsulation.
79
80. Release of the drug from chitosan-TPP, chitosan-FA and
chitosan-GA matrices followed Fick's law of diffusion.
80
81. Spray congealing can be done by spray drying equipment where
protective coating will be applied as a melt.
Core material is dispersed in a coating material melt rather than a
coating solution.
Coating solidification is accomplished by spraying the hot mixture
into cool air stream.
81
82. Waxes, fatty acids, and alcohols, polymers which are solids at
room temperature but meltable at reasonable temperature are
applicable to spray congealing.
82
85. Spinning Disk
85
Suspensions of core particles in liquid shell material are
poured into a rotating disc.
Due to the spinning action of the disc, the core particles
become coated with the shell material.
The coated particles are then cast from the edge of the disc
by centrifugal force.
After that the shell material is solidified by external means
(usually cooling).
This technology is rapid, cost-effective, relatively simple and
has high production efficiencies.
87. SOLVENT EVAPORATION
Solvent evaporation techniques are carried out in a liquid
manufacturing vehicle (O/W emulsion) which is prepared by
agitation of two immiscible liquids.
The process involves dissolving microcapsule coating
(polymer) in a volatile solvent which is immiscible with the
liquid manufacturing vehicle phase.
A core material (drug) to be microencapsulated is dissolved or
dispersed in the coating polymer solution. 88
88. With agitation, the core – coating material mixture is dispersed
in the liquid manufacturing vehicle phase to obtain appropriate
size microcapsules.
Agitation of system is continued until the solvent partitions into
the aqueous phase and is removed by evaporation.
This process results in hardened microspheres which contain
the active moiety.
88
89. Several methods can be used to achieve dispersion
of the oil phase in the continuous phase.
The most common method is the use of a propeller style blade
attached to a variable speed motor.
Various process variables include methods of forming
dispersions, Evaporation rate of the solvent for the coating
polymer, temperature cycles and agitation rates.
89
90. Important factors that must be considered in solvent
evaporation techniques include choice of
-vehicle phase and
-solvent for the polymer coating.
These choice greatly influence microcapsule properties as
well as the choice of solvent recovery techniques.
The solvent evaporation technique is applicable to a wide
variety of liquid and solid core materials.
90
91. The core materials may be either water soluble or water
insoluble materials.
A variety of film forming polymers can be used as coatings.
91
92. ELECTROSTATIC
92
DEPOSITION
This method is suitable for both solid and liquid droplets
Core and coating material are imparted electric charges by means of
high voltage.
Core is charged and placed in coating chamber.
93. Coating material is charged in solution when it leaves the
atomizer device prior to spray as a mist.
93
Since both are oppositely charged coating material gets
deposited on core due to electrostatic attraction.
94. VACCUM
94
DEPOSITION
This is not a popular technique.
Coating material is vapourised in chamber in which core material
is present.
Coating material gets deposited on core particles.
Core particles are moved on conveyor system and they encounter
hot vapours of coating material Which gets deposited on them
95. POLYMERIZATION
95
A relatively new microencapsulation method utilizes
polymerization techniques to form protective microcapsule.
The methods involve the reaction of monomeric units
located at the interface existing between a core material
substance and a continuous phase in which the core material
is dispersed.
96. Interfacial polymerization ( IFP)
96
The capsule shell will be formed at the surface of the droplet
or
particle by polymerization of the reactive monomers.
The substances used are multifunctional monomers.
Generally used monomers include multifunctional isocyanates
and multifunctional acid chlorides.
These will be used either individually on in combination.
97. The multifunctional monomer dissolved in liquid core
material
it will be dispersed in aqueous phase containing dispersing
agent.
A coreactant multifunctional amine will be added to the
mixture.
This results in rapid polymerization at interface and
generation of capsuleshell takes place.
97
98. A polyurea shell will be formed when isocyanate reacts
with amine,
polynylon or polyamide shell will be formed when acid
chloride reacts with amine.
When isocyanate reacts with hydroxyl containing
monomer produces polyurethane shell.
98
99. In situ polymerization
99
Like IFP the capsule shell formation occurs because of
polymerization of monomers.
In this process no reactive agents are added to the core material.
polymerization occurs exclusively in the continuous phase and
on
the continuous phase side of the interface formed by the dispersed
core material and continuous phase.
100. Initially a low molecular weight prepolymer will be formed,
as time goes on the prepolymer grows in size.
it deposits on the surface of the dispersed core material there
by generating solid capsule shell.
100
101. APPLICATIONS OF MICROENCAPSULATION
101
The technology has been used widely in the design of controlled
release and sustained release dosage forms.
To mask the bitter taste of drugs like Paracetamol,
Nitrofurantoin etc.
to reduce gastric and other G.I. tract irritations.
102. Sustained release Aspirin preparations have been reported to
cause significantly less G.I. bleeding than conventional
preparations.
A liquid can be converted to a pseudo-solid for easy
handling and storage. eg.Eprazinone.
102
103. Hygroscopic properties of core materials may be reduced by
microencapsulation e.g. Sodium chloride.
Carbon tetra chlorides and a number of other substances have
been microencapsulated to reduce their odour and volatility.
Microencapsulation has been employed to provide protection to
the core materials against atmospheric effects, e.g.Vit.A.Palmitate.
103
104. Separation of incompatible substance has been achieved by
encapsulation.
104
105. PHYSICOCHEMICAL EVALUATION
105
CHARACTERIZATION:
The characterization of the microparticulate carrier is
important, which helps to design a suitable carrier for the
proteins, drug or antigen delivery.
These microspheres have different microstructures.
These microstructures determine the release and the stability
of
the carrier.
106. SIEVE ANALYSIS
Separation of the microspheres into various size fractions can be
determined by using a mechanical sieve shaker.
A series of five standard stainless steel sieves (20, 30, 45, 60 and
80 mesh) are arranged in the order of decreasing aperture size.
Five grams of drug loaded microspheres are placed on the upper-
most sieve.
The sieves are shaken for a period of about 10 min, and then the
particles on the screen are weighed. 107
109. ATOMIC FORCE MICROSCOPY
(AFM)
109
A Multimode Atomic Force Microscope form Digital
Instrument is used to study the surface morphology of
the microspheres.
111. PARTICLE SIZE
111
Particle size determination:
approximately 30 mg microparticles is redispersed in 2–3 ml
distilled water, containing 0.1% (m/m) Tween20 for 3 min, using
ultrasound.
then transferred into the small volume recirculating unit, operating
at 60 ml/ s.
The microparticle size can be determined by laser diffractometry.
114. POLYMER SOLUBILITY IN THE
SOLVENTS
114
Solution turbidity is a strong indication of solvent power .
The cloud point can be used for the determination of the
solubility of the polymer in different organic solvents.
115. VISCOSITY OF THE POLYMER SOLUTIONS
115
The absolute viscosity, kinematic viscosity, and the intrinsic
viscosity of the polymer solutions in different solvents can
be measured by a U-tube viscometer.
The polymer solutions are allowed to stand for 24 h prior to
measurement to ensure complete polymer dissolution.
117. DENSITY DETERMINATION
117
The density of the microspheres can be measured by using
a multi volume pychnometer.
Accurately weighed sample in a cup is placed into the
multi volume pychnometer.
Helium is introduced at a constant pressure in the chamber
and allowed to expand. This expansion results in a decrease
in pressure within the chamber.
118. Two consecutive readings of reduction in pressure at different
initial pressure are noted.
From two pressure readings the volume and density of the
microsphere carrier is determined.
118
120. BULK DENSITY
120
The microspheres fabricated are weighed and transferred to a
10-ml glass graduated cylinder.
The cylinder is tapped until the microsphere bed volume is
stabilised.
The bulk density is estimated by the ratio of microsphere
weight to the final volume of the tapped microsphere bed.
122. CAPTURE EFFICIENCY
The capture efficiency of the microspheres or the percent
entrapment can be determined by allowing washed microspheres to
lyse.
The lysate is then subjected to the determination of active
constituents as per monograph requirement.
The percent encapsulation efficiency is calculated using
equation:
% Entrapment = Actual content/Theoretical content x 100 123
123. ANGLE OF CONTACT
123
The angle of contact is measured to determine the wetting
property of a micro particulate carrier.
To determine the nature of microspheres in terms of
hydrophilicity or hydrophobicity.
This thermodynamic property is specific to solid and affected
by the presence of the adsorbed component.
124. The angle of contact is measured at the solid/air/water
interface.
The advancing and receding angle of contact are measured by
placing a droplet in a circular cell mounted above objective of
inverted microscope.
124
125. IN VITRO METHODS
125
There is a need for experimental methods which allow the
release characteristics and permeability of a drug through
membrane to be determined.
For this purpose, a number of in vitro and in vivo
techniques have been reported.
In vitro drug release studies are employed as a quality
control procedure in pharmaceutical production, in product
development etc.
126. The influence of technologically defined conditions and
difficulty in simulating in vivo conditions has led to development
of a number of in vitro release methods for buccal formulations;
however no standard in vitro method has yet been developed.
Different workers have used apparatus of varying designs and
under varying conditions, depending on the shape and application
of the dosage form developed
126
127. BEAKER METHOD
127
The dosage form in this method is made to adhere at the
bottom of the beaker containing the medium and stirred
uniformly using over head stirrer.
Volume of the medium used in the literature for the
-studies varies from 50- 500 ml
-stirrer speed form 60-300 rpm.
128. DISSOLUTION APPARATUS
128
Standard USP or BP dissolution apparatus have been
used to study in vitro release profiles.
Dissolution medium used for the study varied from
100-500 ml and speed of rotation from 50-100 rpm.
130. ADVANTAGES
130
Reliable means to deliver the drug to the target site with
specificity.
The desired concentration can be maintained at the site of
interest without untoward effects .
Solid biodegradable microspheres have the potential for
the controlled release of drug.
131. Microspheres received much attention for targeting of
anticancer drugs to the tumour.
The size, surface charge and surface hydrophilicity of
microspheres are found to be important in determining the fate
of
particles in vivo.
Studies on the macrophage uptake of microspheres have
demonstrated their potential in targeting drugs to pathogens
residing intracellularly.
131
132. CONCLUSION
132
The microencapsulation technique offers a variety of
opportunities such as
Protection.
Masking.
reduced dissolution rate.
facilitation of handling.
targeting of the active ingredient.
133. facilitates accurate delivery of small quantities of potent drugs.
reduced drug concentrations at sites other than the target
organ
or tissue.
protection of labile compounds before and after administration
and prior to appearance at the site of action.
In future by combining various other approaches,
microencapsulation technique will find the vital place in novel
drug delivery system. 134
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Pharmaceutical Dosage Forms and Drug
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Pubication;2005;8:265.
2.N.K.Jain, Controlled and Novel drug
delivery, 04 Edition, 236-237, 21.
3.S.P.Vyas and R.K.Khar, Targeted and
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The Theory and Practice of Industrial
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The Science and Practice
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