Liposomes are small artificial vesicles created from cholesterol and phospholipids that resemble cell membranes. They are promising for drug delivery due to their biocompatibility and ability to encapsulate both hydrophilic and hydrophobic drugs. Liposomes are classified based on size, number of bilayers, composition, and preparation method. They can be prepared using techniques like film hydration, extrusion, sonication, and solvent injection. Coating liposomes with polymers like PEG creates stealth liposomes that have longer circulation times in the body.
This document discusses niosomes, which are non-ionic surfactant vesicles that can be used as drug carriers. Niosomes are formed using cholesterol and nonionic surfactants through techniques like thin film hydration, sonication, microfluidization. They can encapsulate both hydrophilic and lipophilic drugs. Compared to liposomes, niosomes are more stable and less expensive to produce. Niosomes show potential for targeted drug delivery and sustained release, making them a promising drug delivery system.
Nanoparticles are nanometer-sized carriers that can be used to deliver drugs and biomolecules. They have unique properties due to their small size. Various methods are used to prepare nanoparticles including emulsion-solvent evaporation, salting out, and supercritical fluid technology. Nanoparticles are characterized based on their size, morphology, surface charge, and hydrophobicity using techniques like electron microscopy and zeta potential measurements. Particle size affects properties like drug release rate and stability of the nanoparticle dispersion.
The document discusses niosomes, which are vesicles composed of non-ionic surfactants that can encapsulate both hydrophilic and hydrophobic drugs. Niosomes offer advantages over liposomes like greater stability and easier production and storage. The document describes various methods for preparing niosomes, factors that affect their formation, characterization techniques, and applications like transdermal drug delivery and targeted drug delivery.
Monoclonal antibodies are produced through the fusion of antibody-producing B cells with myeloma cells, creating a hybridoma that produces antibodies with a single specificity. They have applications in diagnosis, therapy, protein purification, and other areas. For diagnosis, they are used in biochemical assays and diagnostic imaging. Therapeutically, they can directly target conditions or be linked to toxins/drugs to target delivery. They are also useful for purifying specific proteins through immunoaffinity chromatography. Other applications include catalytic monoclonal antibodies and using them for autoantibody fingerprinting to identify individuals.
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.
This document summarizes a seminar presentation on niosomes. Niosomes are non-ionic surfactant based vesicles that can encapsulate both hydrophilic and lipophilic drugs for drug delivery purposes. They have advantages over liposomes such as being less expensive to produce and more stable. The document discusses the structure of niosomes, factors that affect their preparation, common preparation methods, characterization techniques, applications for drug delivery, and their toxicity profile.
Liposomes are spherical vesicles made of phospholipid bilayers that can encapsulate drugs, vaccines, and other substances for delivery to target cells. They are composed of phospholipids, cholesterol, and other lipids arranged in concentric spherical bilayers with an inner aqueous core. Various methods are used to prepare liposomes of different sizes, ranging from multi-lamellar vesicles to small unilamellar vesicles. Key methods include film hydration, extrusion, sonication, freeze/thaw cycles, and detergent removal techniques. Liposomes offer advantages like low toxicity and targeted delivery but also have challenges like short half-life, batch-to-batch variation, and high production costs.
This document provides an introduction to targeted drug delivery and summarizes key points about nanoparticles and liposomes. It discusses advantages of targeted delivery including reducing toxicity and maximizing therapeutic effects. Nanoparticles and liposomes are described as methods for targeted delivery. Key preparation techniques for nanoparticles include solvent evaporation, double emulsification, and nano precipitation. Evaluation parameters like particle size, zeta potential, and in vitro drug release are also summarized. The document concludes with describing applications of liposomes for drug and gene delivery.
This document discusses niosomes, which are non-ionic surfactant vesicles that can be used as drug carriers. Niosomes are formed using cholesterol and nonionic surfactants through techniques like thin film hydration, sonication, microfluidization. They can encapsulate both hydrophilic and lipophilic drugs. Compared to liposomes, niosomes are more stable and less expensive to produce. Niosomes show potential for targeted drug delivery and sustained release, making them a promising drug delivery system.
Nanoparticles are nanometer-sized carriers that can be used to deliver drugs and biomolecules. They have unique properties due to their small size. Various methods are used to prepare nanoparticles including emulsion-solvent evaporation, salting out, and supercritical fluid technology. Nanoparticles are characterized based on their size, morphology, surface charge, and hydrophobicity using techniques like electron microscopy and zeta potential measurements. Particle size affects properties like drug release rate and stability of the nanoparticle dispersion.
The document discusses niosomes, which are vesicles composed of non-ionic surfactants that can encapsulate both hydrophilic and hydrophobic drugs. Niosomes offer advantages over liposomes like greater stability and easier production and storage. The document describes various methods for preparing niosomes, factors that affect their formation, characterization techniques, and applications like transdermal drug delivery and targeted drug delivery.
Monoclonal antibodies are produced through the fusion of antibody-producing B cells with myeloma cells, creating a hybridoma that produces antibodies with a single specificity. They have applications in diagnosis, therapy, protein purification, and other areas. For diagnosis, they are used in biochemical assays and diagnostic imaging. Therapeutically, they can directly target conditions or be linked to toxins/drugs to target delivery. They are also useful for purifying specific proteins through immunoaffinity chromatography. Other applications include catalytic monoclonal antibodies and using them for autoantibody fingerprinting to identify individuals.
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.
This document summarizes a seminar presentation on niosomes. Niosomes are non-ionic surfactant based vesicles that can encapsulate both hydrophilic and lipophilic drugs for drug delivery purposes. They have advantages over liposomes such as being less expensive to produce and more stable. The document discusses the structure of niosomes, factors that affect their preparation, common preparation methods, characterization techniques, applications for drug delivery, and their toxicity profile.
Liposomes are spherical vesicles made of phospholipid bilayers that can encapsulate drugs, vaccines, and other substances for delivery to target cells. They are composed of phospholipids, cholesterol, and other lipids arranged in concentric spherical bilayers with an inner aqueous core. Various methods are used to prepare liposomes of different sizes, ranging from multi-lamellar vesicles to small unilamellar vesicles. Key methods include film hydration, extrusion, sonication, freeze/thaw cycles, and detergent removal techniques. Liposomes offer advantages like low toxicity and targeted delivery but also have challenges like short half-life, batch-to-batch variation, and high production costs.
This document provides an introduction to targeted drug delivery and summarizes key points about nanoparticles and liposomes. It discusses advantages of targeted delivery including reducing toxicity and maximizing therapeutic effects. Nanoparticles and liposomes are described as methods for targeted delivery. Key preparation techniques for nanoparticles include solvent evaporation, double emulsification, and nano precipitation. Evaluation parameters like particle size, zeta potential, and in vitro drug release are also summarized. The document concludes with describing applications of liposomes for drug and gene delivery.
Aquasomes are spherical nanoparticles 60-300nm in size that are used to deliver drugs and antigens. They are composed of a central ceramic core coated with carbohydrates to protect and preserve fragile biological molecules. The core is typically made of calcium phosphate prepared using methods like sonication or colloidal precipitation. It is then coated with polyhydroxy oligomers like cellobiose or trehalose to stabilize the nanoparticle. Drugs or antigens are then adsorbed onto the coated core. Aquasomes maintain the structural integrity of molecules and deliver them through controlled release while protecting them from degradation. They have applications in delivering substances like insulin, hemoglobin, antigens, enzymes, and genes.
Myself Omkar Tipugade , M pharm , Shree Santkrupa College of Pharmacy , Ghogaon , Karad ( Maharashtra).
I upload the presentation on sun protection & type of Skin and sun screen agent depend on skin type , and also brief information about the cosmetic & cosmeceutical product.
This document discusses microspheres and microencapsulation. It was submitted by Debasish Deka for his M. Pharm degree under the guidance of Ananta Choudhury. It covers the introduction, advantages, limitations, types (e.g. bioadhesive, magnetic, floating), methods of preparation (e.g. solvent evaporation, spray drying), evaluation, and applications of microspheres in pharmaceutical industry (e.g. buccal drug delivery, intratumoral delivery). Microencapsulation is also introduced as enclosing solids, liquids or gases in microscopic particles through thin coatings, with origins in the 1930s business machines industry.
Liposomes are defined as phospholipid vesicles consisting of one or more concentric lipid bilayers enclosing discrete aqueous spaces. The unique ability of liposomal systems to entrap both lipophilic and hydrophilic compounds enables a diverse range of drugs to be encapsulated by these vesicles.
Sunscreen is a topical product that protects skin from the sun's harmful ultraviolet rays. Sunscreens can be physical (reflect UV rays using ingredients like zinc oxide or titanium dioxide) or chemical (absorb UV rays using ingredients like avobenzone). Regulatory standards for sunscreen labeling and testing have been established by organizations like the FDA and EU to help consumers identify effective broad spectrum protection and proper application. Ongoing research evaluates sunscreen safety and ensures protection against sun damage while avoiding potential toxicity issues.
Liposomes are spherical vesicles made of concentric phospholipid bilayers. They were first produced in 1961 and can range in size from 20 nm to several micrometers. Liposomes provide advantages like selective targeting to tumors, increased drug efficacy, and reduced toxicity, but also have disadvantages such as high production costs and drug leakage. Common methods for preparing liposomes include film hydration, ethanol injection, and detergent removal.
The document describes electrosomes, which are a novel surface display system composed of enzymes attached to a scaffoldin protein. This allows for multiple electron release from fuel oxidation. In the anode, an ethanol oxidation cascade is assembled using alcohol dehydrogenase and formaldehyde dehydrogenase enzymes attached to the scaffoldin. In the cathode, copper oxidase is attached for oxygen reduction. The electrosomes provide advantages as a fuel cell and drug delivery system by catalyzing chemical energy conversion to electricity and providing controlled drug release.
This document provides an overview of cleansing and care needs for different body parts including the eyes, lips, nails, scalp, and neck. It discusses the key functions and makeup products for the eyes and lips. Cosmetic products like mascara, eye shadow, lipstick, and nail polish are explained along with their typical formulations. Daily cleaning tips and tools are outlined for taking care of the nails, scalp, and neck. The document concludes by emphasizing the importance of using branded cosmetic products and checking expiration dates.
This document presents information on aquasomes, a novel carrier for drug delivery. Aquasomes are spherical, nanoparticulate carrier systems composed of a solid nanocrystalline core coated with an oligomeric film. They are capable of stabilizing and delivering delicate biomolecules like proteins, peptides, hormones, and genes. The core provides structural stability while the carbohydrate coating protects molecules from degradation. Characterization techniques like TEM, SEM, and DSC are used to analyze aquasome size, structure, and glass transition temperature. Applications include insulin, enzyme, oxygen, antigen and drug delivery where aquasomes show improved stability and biological activity over unformulated drugs.
Niosomes: An excellent tool for drug deliverypharmaindexing
This document summarizes niosomes, which are non-ionic surfactant vesicles that can be used as drug delivery carriers. Niosomes have advantages over liposomes such as being more stable and less expensive to produce. The document discusses the composition of niosomes, methods for preparing niosomes, types of niosomes including multilamellar vesicles and unilamellar vesicles, and how niosomes can improve drug delivery by controlling drug release kinetics and targeting drug delivery.
1. The document discusses various vesicular drug delivery systems including liposomes, ethosomes, transfersomes, phytosomes, sphingosomes, and virosomes.
2. Liposomes are spherical vesicles made of phospholipid bilayers that can encapsulate drugs. Ethosomes are noninvasive vesicles made of water, phospholipids, and ethanol that enable delivery of drugs to deeper skin layers.
3. Transfersomes have enhanced deformability and stability allowing them to deliver drugs across skin barriers. Phytosomes combine herbal extracts with phospholipids to improve solubility and bioavailability. Sphingosomes are similar to liposomes but composed of sphingolipids. Virosomes incorporate viral proteins into phospholipid
This document describes electrosomes, which are a novel surface display system that allows multiple electron release from fuel oxidation using a scaffoldin protein and cascade of redox enzymes. Electrosomes consist of a hybrid anode with ethanol-oxidizing enzymes attached to scaffoldin and a hybrid cathode with an oxygen-reducing enzyme also attached to scaffoldin. This allows the electrosomes to function as both an anode and cathode in a biofuel cell. Characterization of the electrosomes showed they were able to catalyze the conversion of chemical energy from ethanol to electricity with high power outputs due to the enzymatic cascades in the anode. Potential applications of electrosomes include use in enzymatic fuel cells, drug targeting
This document discusses niosomes, which are non-ionic surfactant vesicles similar in structure to liposomes that can be used for drug delivery. Niosomes are formed by the self-assembly of non-ionic surfactants in aqueous solution, resulting in closed bilayer structures that can encapsulate medications. They offer advantages over traditional drugs such as controlled release and increased drug stability. The document describes various methods for preparing and characterizing niosomes as well as their applications, components, and stability.
Niosomes are novel drug delivery systems where medication is encapsulated in a non-ionic surfactant-based vesicle. They are similar to liposomes but are made of surfactant bilayers instead of phospholipid bilayers. Niosomes can be prepared in different sizes and methods to encapsulate both hydrophilic and hydrophobic drugs. They provide advantages over liposomes such as being more stable and having less variability. Niosomes show potential for targeted drug delivery and increasing drug bioavailability.
Cleansing for face,eye lids, lips ,hands, feet,nail,scalp,neck,body & underar...PawanDhamala1
This document discusses various controversial ingredients found in cosmetic products and provides information about them. It covers parabens, formaldehyde liberators, and 1,4-dioxane. For each ingredient, it describes what they are, why they are controversial according to the FDA, relevant regulations, and alternatives. The document aims to inform readers about common controversial ingredients in cosmetics.
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.
The document discusses several methods for preparing liposomes, including mechanical dispersion, solvent dispersion, and detergent removal methods. Mechanical dispersion methods like lipid film hydration and sonication are commonly used to make multilamellar and small unilamellar vesicles. Solvent dispersion methods like ether injection, ethanol injection, and reverse phase evaporation form liposomes by injecting or evaporating organic solvents. The detergent removal method uses detergents to solubilize lipids before removing the detergent to form large unilamellar vesicles. Each method has advantages and drawbacks regarding liposome size, stability, and encapsulation efficiency.
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.
Liposomes-Classification, methods of preparation and application Vijay Hemmadi
liposome preparation and application
A liposome is a tiny bubble (vesicle), made out of the same material as a cell membrane. Liposomes can be filled with drugs, and used to deliver drugs for cancer and other diseases. Membranes are usually made of phospholipids, which are molecules that have a head group and a tail group
liposomes are novel drug delivery dosage systems, where the drug is entrapped in phospholipid bilayered vesicles. the release of drug from the vesicles can be controlled or sustained.
the follwing presentation contain structure, classification and preparation methods, characterization and applications of liposomes.
Aquasomes are spherical nanoparticles 60-300nm in size that are used to deliver drugs and antigens. They are composed of a central ceramic core coated with carbohydrates to protect and preserve fragile biological molecules. The core is typically made of calcium phosphate prepared using methods like sonication or colloidal precipitation. It is then coated with polyhydroxy oligomers like cellobiose or trehalose to stabilize the nanoparticle. Drugs or antigens are then adsorbed onto the coated core. Aquasomes maintain the structural integrity of molecules and deliver them through controlled release while protecting them from degradation. They have applications in delivering substances like insulin, hemoglobin, antigens, enzymes, and genes.
Myself Omkar Tipugade , M pharm , Shree Santkrupa College of Pharmacy , Ghogaon , Karad ( Maharashtra).
I upload the presentation on sun protection & type of Skin and sun screen agent depend on skin type , and also brief information about the cosmetic & cosmeceutical product.
This document discusses microspheres and microencapsulation. It was submitted by Debasish Deka for his M. Pharm degree under the guidance of Ananta Choudhury. It covers the introduction, advantages, limitations, types (e.g. bioadhesive, magnetic, floating), methods of preparation (e.g. solvent evaporation, spray drying), evaluation, and applications of microspheres in pharmaceutical industry (e.g. buccal drug delivery, intratumoral delivery). Microencapsulation is also introduced as enclosing solids, liquids or gases in microscopic particles through thin coatings, with origins in the 1930s business machines industry.
Liposomes are defined as phospholipid vesicles consisting of one or more concentric lipid bilayers enclosing discrete aqueous spaces. The unique ability of liposomal systems to entrap both lipophilic and hydrophilic compounds enables a diverse range of drugs to be encapsulated by these vesicles.
Sunscreen is a topical product that protects skin from the sun's harmful ultraviolet rays. Sunscreens can be physical (reflect UV rays using ingredients like zinc oxide or titanium dioxide) or chemical (absorb UV rays using ingredients like avobenzone). Regulatory standards for sunscreen labeling and testing have been established by organizations like the FDA and EU to help consumers identify effective broad spectrum protection and proper application. Ongoing research evaluates sunscreen safety and ensures protection against sun damage while avoiding potential toxicity issues.
Liposomes are spherical vesicles made of concentric phospholipid bilayers. They were first produced in 1961 and can range in size from 20 nm to several micrometers. Liposomes provide advantages like selective targeting to tumors, increased drug efficacy, and reduced toxicity, but also have disadvantages such as high production costs and drug leakage. Common methods for preparing liposomes include film hydration, ethanol injection, and detergent removal.
The document describes electrosomes, which are a novel surface display system composed of enzymes attached to a scaffoldin protein. This allows for multiple electron release from fuel oxidation. In the anode, an ethanol oxidation cascade is assembled using alcohol dehydrogenase and formaldehyde dehydrogenase enzymes attached to the scaffoldin. In the cathode, copper oxidase is attached for oxygen reduction. The electrosomes provide advantages as a fuel cell and drug delivery system by catalyzing chemical energy conversion to electricity and providing controlled drug release.
This document provides an overview of cleansing and care needs for different body parts including the eyes, lips, nails, scalp, and neck. It discusses the key functions and makeup products for the eyes and lips. Cosmetic products like mascara, eye shadow, lipstick, and nail polish are explained along with their typical formulations. Daily cleaning tips and tools are outlined for taking care of the nails, scalp, and neck. The document concludes by emphasizing the importance of using branded cosmetic products and checking expiration dates.
This document presents information on aquasomes, a novel carrier for drug delivery. Aquasomes are spherical, nanoparticulate carrier systems composed of a solid nanocrystalline core coated with an oligomeric film. They are capable of stabilizing and delivering delicate biomolecules like proteins, peptides, hormones, and genes. The core provides structural stability while the carbohydrate coating protects molecules from degradation. Characterization techniques like TEM, SEM, and DSC are used to analyze aquasome size, structure, and glass transition temperature. Applications include insulin, enzyme, oxygen, antigen and drug delivery where aquasomes show improved stability and biological activity over unformulated drugs.
Niosomes: An excellent tool for drug deliverypharmaindexing
This document summarizes niosomes, which are non-ionic surfactant vesicles that can be used as drug delivery carriers. Niosomes have advantages over liposomes such as being more stable and less expensive to produce. The document discusses the composition of niosomes, methods for preparing niosomes, types of niosomes including multilamellar vesicles and unilamellar vesicles, and how niosomes can improve drug delivery by controlling drug release kinetics and targeting drug delivery.
1. The document discusses various vesicular drug delivery systems including liposomes, ethosomes, transfersomes, phytosomes, sphingosomes, and virosomes.
2. Liposomes are spherical vesicles made of phospholipid bilayers that can encapsulate drugs. Ethosomes are noninvasive vesicles made of water, phospholipids, and ethanol that enable delivery of drugs to deeper skin layers.
3. Transfersomes have enhanced deformability and stability allowing them to deliver drugs across skin barriers. Phytosomes combine herbal extracts with phospholipids to improve solubility and bioavailability. Sphingosomes are similar to liposomes but composed of sphingolipids. Virosomes incorporate viral proteins into phospholipid
This document describes electrosomes, which are a novel surface display system that allows multiple electron release from fuel oxidation using a scaffoldin protein and cascade of redox enzymes. Electrosomes consist of a hybrid anode with ethanol-oxidizing enzymes attached to scaffoldin and a hybrid cathode with an oxygen-reducing enzyme also attached to scaffoldin. This allows the electrosomes to function as both an anode and cathode in a biofuel cell. Characterization of the electrosomes showed they were able to catalyze the conversion of chemical energy from ethanol to electricity with high power outputs due to the enzymatic cascades in the anode. Potential applications of electrosomes include use in enzymatic fuel cells, drug targeting
This document discusses niosomes, which are non-ionic surfactant vesicles similar in structure to liposomes that can be used for drug delivery. Niosomes are formed by the self-assembly of non-ionic surfactants in aqueous solution, resulting in closed bilayer structures that can encapsulate medications. They offer advantages over traditional drugs such as controlled release and increased drug stability. The document describes various methods for preparing and characterizing niosomes as well as their applications, components, and stability.
Niosomes are novel drug delivery systems where medication is encapsulated in a non-ionic surfactant-based vesicle. They are similar to liposomes but are made of surfactant bilayers instead of phospholipid bilayers. Niosomes can be prepared in different sizes and methods to encapsulate both hydrophilic and hydrophobic drugs. They provide advantages over liposomes such as being more stable and having less variability. Niosomes show potential for targeted drug delivery and increasing drug bioavailability.
Cleansing for face,eye lids, lips ,hands, feet,nail,scalp,neck,body & underar...PawanDhamala1
This document discusses various controversial ingredients found in cosmetic products and provides information about them. It covers parabens, formaldehyde liberators, and 1,4-dioxane. For each ingredient, it describes what they are, why they are controversial according to the FDA, relevant regulations, and alternatives. The document aims to inform readers about common controversial ingredients in cosmetics.
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.
The document discusses several methods for preparing liposomes, including mechanical dispersion, solvent dispersion, and detergent removal methods. Mechanical dispersion methods like lipid film hydration and sonication are commonly used to make multilamellar and small unilamellar vesicles. Solvent dispersion methods like ether injection, ethanol injection, and reverse phase evaporation form liposomes by injecting or evaporating organic solvents. The detergent removal method uses detergents to solubilize lipids before removing the detergent to form large unilamellar vesicles. Each method has advantages and drawbacks regarding liposome size, stability, and encapsulation efficiency.
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.
Liposomes-Classification, methods of preparation and application Vijay Hemmadi
liposome preparation and application
A liposome is a tiny bubble (vesicle), made out of the same material as a cell membrane. Liposomes can be filled with drugs, and used to deliver drugs for cancer and other diseases. Membranes are usually made of phospholipids, which are molecules that have a head group and a tail group
liposomes are novel drug delivery dosage systems, where the drug is entrapped in phospholipid bilayered vesicles. the release of drug from the vesicles can be controlled or sustained.
the follwing presentation contain structure, classification and preparation methods, characterization and applications of liposomes.
Liposomal drug delivery systems an overviewsana916816
1. Liposomes are spherical vesicles made of phospholipid bilayers that encapsulate aqueous volume. They were first produced in 1961 and can be used to deliver drugs.
2. Liposomes are composed mainly of phospholipids like phosphatidylcholine and cholesterol. Other components include phospholipid head groups, acyl chains, and a glycerol bridge.
3. Liposomes can be formed through various techniques including film hydration, extrusion, sonication, solvent injection, and freeze drying. These methods aim to produce unilamellar or multilamellar liposomes of defined size for drug delivery applications.
Liposomes are spherical vesicles made of phospholipid bilayers that can encapsulate hydrophilic or hydrophobic drugs. They range in size from 25nm to 5000nm. This document discusses the structure of liposomes and their components, including phospholipids and cholesterol. Various preparation methods are described, such as lipid film hydration, ethanol injection, and detergent removal. Liposomes offer advantages for drug delivery, such as the ability to encapsulate different drug types and provide controlled release. They can be classified based on structure, method of preparation, composition, and specialty type.
Liposomes are spherical vesicles made of phospholipid bilayers that can encapsulate drugs for delivery. They range in size from 25nm to 5000nm. Liposomes are prepared through methods like lipid film hydration, microemulsification, sonication, or membrane extrusion. They offer advantages for delivering both hydrophobic and hydrophilic drugs and allow for controlled release. Liposomes can be classified based on their structure, preparation method, composition, and application.
Liposomes are spherical vesicles made of phospholipid bilayers that can encapsulate hydrophilic or hydrophobic drugs. They range in size from 25nm to 5000nm. This document discusses the structure of liposomes and their components, including phospholipids and cholesterol. It also covers various preparation methods such as lipid film hydration, extrusion, and detergent removal. Liposomes offer advantages for drug delivery such as the ability to encapsulate different drug types and provide controlled release, but also have challenges like high production costs and drug leakage.
This document provides an overview of liposomes as a drug delivery system. It begins by defining liposomes as spherical vesicles composed of lipid bilayers that can encapsulate aqueous volumes. Liposomes were first produced in 1961. The document then discusses the composition of liposomes, including phospholipids and cholesterol as main components. It describes various methods for liposome preparation, such as film hydration, sonication, extrusion, and detergent removal. Characterization techniques are also outlined. In summary, this document introduces liposomes as lipid bilayer structures for drug delivery and encapsulation, and covers their composition, methods of preparation, and characterization.
Liposomes are spherical vesicles composed of lipid bilayers that can encapsulate aqueous content. They are used as drug delivery systems to improve drug solubility, stability, and targeting. Liposomes are prepared using various methods involving dispersion of lipids in aqueous solution. Key components are phospholipids like phosphatidylcholine and cholesterol. Characterization evaluates parameters like size, shape, drug entrapment efficiency, and phase behavior. Liposomes offer benefits like increased drug efficacy and stability but also have challenges like short shelf life and high production costs.
This document provides an overview of liposomes, which are spherical vesicles composed of phospholipid bilayers that can encapsulate drugs for delivery. Key points include:
- Liposomes range in size from 25nm to 5000nm and consist of phospholipids, cholesterol, and an encapsulated drug molecule.
- They offer advantages for drug delivery such as ability to encapsulate both hydrophobic and hydrophilic drugs, increase drug stability, and provide controlled release.
- Common methods for preparing liposomes include lipid film hydration, mechanical dispersion techniques like sonication, and detergent removal methods.
- Liposomes have applications in cancer chemotherapy, oral drug delivery, topical applications, pulmonary delivery, and gene delivery due
This document discusses liposomes, which are spherical vesicles made of phospholipids that can encapsulate drugs. It covers the structure of liposomes, how they are formed from phospholipid bilayers, and their advantages like increased drug efficacy and stability. The document also categorizes liposomes based on size, composition, and preparation method. Common preparation techniques include shaking, extrusion, and solvent dispersion. Liposomes are evaluated based on their size, drug encapsulation efficiency, and stability. The document concludes that liposomes have many applications in cancer therapy, oral drug delivery, topical applications, and enhancing antimicrobial efficacy due to their biocompatibility and ability to protect drugs.
Liposomes are artificially created spherical vesicles made of phospholipids and cholesterol that can encapsulate both hydrophilic and hydrophobic drugs. They are promising drug delivery systems due to their biocompatibility and ability to selectively target tissues. Liposomes vary in size from 20-5000 nm and consist of one or more phospholipid bilayers surrounding an aqueous core. There are several methods for preparing and loading drugs into liposomes to develop drug delivery systems with benefits like increased drug efficacy, stability and reduced toxicity.
Liposomes, Structure of liposome, phospholipids, classification of liposomes, method of preparation of liposomes, mechanism of liposome formation, application of liposomes.
This document discusses liposomes, which are spherical vesicles made of lipid bilayers that can encapsulate drugs for targeted drug delivery. Liposomes have a microscopic spherical structure and are made of one or more concentric lipid bilayers composed of natural or synthetic phospholipids. They can encapsulate both hydrophilic and hydrophobic drugs within their aqueous interior or lipid bilayer. The main components of liposomes are phospholipids and cholesterol. Phosphatidylcholine is a commonly used phospholipid that has a hydrophilic head and hydrophobic tails. Cholesterol is also incorporated and affects the fluidity and permeability of the membrane. Liposomes are classified based on structure, method of preparation, composition, and provide advantages like targeted drug delivery and
1. Liposomes are spherical vesicles made of phospholipid bilayers that can encapsulate aqueous content. They range in size from 20nm to micrometers.
2. Liposomes are composed mainly of phospholipids and cholesterol. Commonly used phospholipids include phosphatidylcholine, phosphatidylethanolamine, and dioleoyl phosphatidylcholine. Cholesterol helps stabilize the bilayer structure.
3. Liposomes offer advantages like low toxicity, biodegradability, protection of encapsulated drugs, and improved pharmacokinetics. However, they also have disadvantages such as drug leakage, short half-life, high production costs, and difficulty in large-scale manufacturing
This document provides an overview of liposomes, including their composition, advantages, classification, preparation methods, characterization, and applications. Liposomes are spherical vesicles composed of phospholipid bilayers that can encapsulate drugs. They range in size from 20nm to several micrometers. Key advantages include biodegradability, protection of encapsulated drugs, and improved drug pharmacokinetics. Common preparation methods include mechanical dispersion, solvent dispersion, and detergent removal. Liposomes are characterized based on size, surface charge, drug entrapment percentage, and lamellarity. They have applications as drug and gene delivery vehicles in cancer therapy, antimicrobial therapy, and more.
liposomes used in preparation of both hydrophilic and hudrophobic drug.
it increases therapeutic efficiency by site targeting and increase circulatory time.
This document provides an overview of liposomes, including their composition, mechanisms of formation, advantages, classifications, preparation methods, applications, and examples of marketed products. Liposomes are spherical vesicles composed of phospholipid bilayers that can encapsulate both hydrophilic and hydrophobic drugs. They are classified based on structural parameters like lamellarity and size, as well as composition. Common preparation techniques include thin film hydration, ethanol injection, sonication, and microfluidization. Liposomes are useful for targeted drug delivery to treat conditions like cancer and fungal infections, and some commercial liposome products are used to deliver drugs like amphotericin B and daunorubicin.
Vesicles are colloidal particles in which a concentric bilayer made-up of amphiphilic molecules surrounds an aqueous compartment Useful vehicle for drug delivery of both hydrophobic drugs and hydrophilic drugs, which are encapsulated in the interior aqueous compartment.
Niosomes are novel drug delivery systems composed of non-ionic surfactants and cholesterol. They can encapsulate both hydrophilic and lipophilic drugs. Niosomes are prepared using methods like ether injection, film hydration, sonication, and microfluidization. Key factors that affect niosome formation include the surfactant used, addition of cholesterol, and hydration temperature. Niosomes offer advantages over liposomes like improved stability and the ability to entrap both hydrophilic and hydrophobic drugs. Niosomes find applications in targeted drug delivery through routes like transdermal, parenteral, oral and for ophthalmic and radiopharmaceutical uses.
ISO/IEC 27001, ISO/IEC 42001, and GDPR: Best Practices for Implementation and...PECB
Denis is a dynamic and results-driven Chief Information Officer (CIO) with a distinguished career spanning information systems analysis and technical project management. With a proven track record of spearheading the design and delivery of cutting-edge Information Management solutions, he has consistently elevated business operations, streamlined reporting functions, and maximized process efficiency.
Certified as an ISO/IEC 27001: Information Security Management Systems (ISMS) Lead Implementer, Data Protection Officer, and Cyber Risks Analyst, Denis brings a heightened focus on data security, privacy, and cyber resilience to every endeavor.
His expertise extends across a diverse spectrum of reporting, database, and web development applications, underpinned by an exceptional grasp of data storage and virtualization technologies. His proficiency in application testing, database administration, and data cleansing ensures seamless execution of complex projects.
What sets Denis apart is his comprehensive understanding of Business and Systems Analysis technologies, honed through involvement in all phases of the Software Development Lifecycle (SDLC). From meticulous requirements gathering to precise analysis, innovative design, rigorous development, thorough testing, and successful implementation, he has consistently delivered exceptional results.
Throughout his career, he has taken on multifaceted roles, from leading technical project management teams to owning solutions that drive operational excellence. His conscientious and proactive approach is unwavering, whether he is working independently or collaboratively within a team. His ability to connect with colleagues on a personal level underscores his commitment to fostering a harmonious and productive workplace environment.
Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
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Pride Month Slides 2024 David Douglas School District
Liposomes dr. asm
1. liposomes
Dr. Atish S. Mundada
Associate Professor,
SNJB’s SSDJ College of Pharmacy,
Chandwad, Dist. Nashik
2. Introduction:Introduction:
• The name liposome is derived from two Greek words: 'Lipos'
meaning fat and 'Soma' meaning body.
• Liposomes were first described by British haematologist Dr Alec D
Bangham in 1961 at the Babraham Institute, in Cambridge.
• They were discovered when Bangham and R. W. Horne were
testing the institute's new electron microscope by adding
negative stain to dry phospholipids. The microscope pictures
served as the first real evidence for the liposomes resemblance to
the cell membrane like a bilayer lipid structure.
• Liposomes are small artificial vesicles of spherical shape that can
be created from cholesterol and natural nontoxic phospholipids.
• Generally, liposomes are definite as spherical vesicles with
particle sizes ranging from 30 nm to several micrometers.
• Due to their size and hydrophobic and hydrophilic character
(besides biocompatibility), liposomes are promising systems for
drug delivery.
3. • Liposome properties differ considerably with lipid composition,
surface charge, size, and the method of preparation.
• Furthermore, the choice of bilayer components determines the
‘rigidity’ or ‘fluidity’ and the charge of the bilayer.
• For instance, unsaturated phosphatidylcholine species from
natural sources (egg or soybean phosphatidylcholine) give much
more permeable and less stable bilayers, whereas the saturated
phospholipids with long acyl chains (for example, dipalmitoylphos
phatidylcholine) form a rigid, rather impermeable bilayer
structure.
• Because of their biocompatibility, biodegradability, low toxicity,
and aptitude to trap both hydrophilic and lipophilic drugs and
simplify site-specific drug delivery to tumor tissues, liposomes
have increased rate both as an investigational system and
commercially as a drug delivery system.
4. Advantages of liposome:-
• Liposomes increased efficacy and therapeutic index of drug
(actinomycin-D)
• Liposome increased stability via encapsulation
• Liposomes are non-toxic, flexible, biocompatible, completely
biodegradable, and nonimmunogenic for systemic and non-
systemic administrations
• Liposomes reduce the toxicity of the encapsulated agent
(amphotericin B, Taxol)
• Liposomes help reduce the exposure of sensitive tissues to toxic
drugs
• Flexibility to couple with site-specific ligands to achieve active
targeting
5. Disadvantages of liposome:-
• Low solubility
• Sterilization
• Short half-life
• Sometimes phospholipid undergoes oxidation and hydrolysis-like
reaction
• Leakage and fusion of encapsulated drug/ molecules
• Production cost is high
• Fewer stables
6. Classification of liposomes:Classification of liposomes:
• Based on the size and number of bilayers:
• Multilamellar vesicles (MLV),
• Large unilamellar vesicles (LUV) and
• Small unilamellar vesicles (SUV).
• Based on composition:
• Conventional liposomes (CL),
• pH-sensitive liposomes,
• Cationic liposomes,
• Long circulating liposomes (LCL) and
• Immuno-liposomes.
• Based on the method of preparation:
• Reverse phase evaporation vesicles (REV),
• French press vesicles (FPV) and
• Ether injection vesicles (EIV)
7.
8.
9. Methods of liposome preparation:Methods of liposome preparation:
• The correct choice of liposome preparation method depends on
the following parameters:
1) The physicochemical characteristics of the material to be
entrapped and those of the liposomal ingredients;
2) The nature of the medium in which the lipid vesicles are
dispersed;
3) The effective concentration of the entrapped substance and its
potential toxicity;
4) Additional processes involved during application/ delivery of the
vesicles;
5) Optimum size, polydispersity and shelf-life of the vesicles for the
intended application and
6) Batch-to-batch reproducibility and possibility of large-scale
production of safe and efficient liposomal products.
10.
11. • All the methods of preparing the liposomes involve four basic
stages:
– Drying down lipids from organic solvent.
– Dispersing the lipid in aqueous media.
– Purifying the resultant liposome.
– Analyzing the final product.
• Handling of Liposomes:
• The lipids used in the preparation of liposomes are unsaturated
and hence susceptible to oxidation.
• Volatile solvents such as chloroform which are used will tend to
evaporate from the container.
• Thus liposomes must be stored in an inert atmosphere of
nitrogen and in the dark, in glass vessels with a securely fastened
cap.
12. Preparation of liposomes by lipid film hydration:
• When preparing liposomes with mixed lipid composition, the
lipids must first be dissolved and mixed in an organic solvent to
assure a homogeneous mixture of lipids.
• Usually this process is carried out using chloroform or chloroform:
methanol mixtures. The intent is to obtain a clear lipid solution for
complete mixing of lipids.
• Typically lipid solutions are prepared at 10-20mg lipid/ml of
organic solvent, although higher concentrations may be used if the
lipid solubility and mixing are acceptable.
• Once the lipids are thoroughly mixed in the organic solvent, the
solvent is removed to yield a lipid film.
• For small volumes of organic solvent (<1mL), the solvent may be
evaporated using a dry nitrogen or argon stream in a fume hood.
For larger volumes, the organic solvent should be removed by
rotary evaporation yielding a thin lipid film on the sides of a round
bottom flask.
Mechanical Dispersion Method:Mechanical Dispersion Method:
13. • The lipid film is thoroughly dried to remove residual organic
solvent by placing the vial or flask on a vacuum pump overnight.
• Hydration of the dry lipid film/cake is accomplished simply by
adding an aqueous medium to the container of dry lipid and
agitating.
• The temperature of the hydrating medium should be above the
gel liquid crystal transition temperature (Tc or Tm) of the lipid.
• After addition of the hydrating medium, the lipid suspension
should be maintained above the Tc during the hydration period.
• Spinning the round bottom flask in the warm water bath
maintained at a temperature above the Tc of the lipid suspension
allows the lipid to hydrate in its fluid phase with adequate
agitation.
• Hydration time may differ slightly among lipid species and
structure, however, a hydration time of 1 hour with vigorous
shaking, mixing, or stirring is highly recommended.
14. • The hydration medium is generally determined by the application
of the lipid vesicles.
• Suitable hydration media include distilled water, buffer solutions,
saline, and non-electrolytes such as sugar solutions. Generally
accepted solutions which meet these conditions are 0.9% saline,
5% dextrose and 10% sucrose.
• During hydration some lipids form complexes unique to their
structure. Highly charged lipids have been observed to form a
viscous gel when hydrated with low ionic strength solutions. The
problem can be alleviated by addition of salt or by downsizing the
lipid suspension.
• Poorly hydrating lipids such as phosphatidyl ethanolamine have a
tendency to self aggregate upon hydration.
15. Sonication:
• Sonication is perhaps the most extensively used method for the
preparation of SUV. Here, MLVs are sonicated either with a bath
type sonicator or a probe sonicator under a passive atmosphere.
• The main disadvantages of this method are very low internal
volume/ encapsulation efficacy, possible degradation of
phospholipids and compounds to be encapsulated, elimination of
large molecules, metal pollution from probe tip, and presence of
MLV along with SUV.
There are two sonication techniques:
• a) Probe sonication: The tip of a sonicator is directly engrossed
into the liposome dispersion.
• b) Bath sonication: The liposome dispersion in a cylinder is placed
into a bath sonicator.
16. French pressure cell:
• Extrusion French pressure cell involves the extrusion of MLV
through a small orifice at 20,000 psi at 4°C.
• An interesting comment is that French press vesicle appears to
recall entrapped solutes significantly longer than SUVs do,
produced by sonication or detergent removal.
• The method has several advantages over sonication method.
– The method is simple, rapid and reproducible and it involves
gentle handling of unstable materials.
– The resulting liposomes are rather larger than sonicated SUVs.
• The drawbacks of the method are that
– the high temperature is difficult to attain, and
– the working volumes are comparatively small (about 50 mL as
the maximum).
17. Freeze-thawed liposomes:
• SUVs are rapidly frozen and thawed slowly. The short-lived
sonication disperses aggregated materials to LUV. The creation of
unilamellar vesicles is as a result of the fusion of SUV throughout
the processes of freezing and thawing.
• This type of synthesis is strongly inhibited by increasing the
phospholipid concentration and by increasing the ionic strength of
the medium.
• The encapsulation efficacies from 20% to 30% were obtained.
18. Solvent dispersion method:Solvent dispersion method:
Ether injection (solvent vaporization):
• A solution of lipids dissolved in diethyl ether or ether-methanol
mixture is gradually injected to an aqueous solution of the
material to be encapsulated at 55°C to 65°C or under reduced
pressure.
• The consequent removal of ether under vacuum leads to the
creation of liposomes.
• The main disadvantages of the technique are that the population
is heterogeneous (70 to 200 nm) and the exposure of compounds
to be encapsulated to organic solvents at high temperature.
19. Ethanol injection:
• A lipid solution of ethanol is rapidly injected to a huge excess of
buffer. The MLVs are at once formed.
• The disadvantages of the method are
– that the population is heterogeneous (30 to 110 nm),
– liposomes are very dilute,
– the removal all ethanol is difficult because it forms into
azeotrope with water, and
– the probability of the various biologically active
macromolecules to inactivate in the presence of even low
amounts of ethanol is high.
20. Reverse phase evaporation method:-
• This method provided a progress in liposome technology, since it
allowed for the first time the preparation of liposomes with a high
aqueous space-to-lipid ratio and a capability to entrap a large
percentage of the aqueous material presented.
• Reverse-phase evaporation is based on the creation of inverted
micelles. These inverted micelles are shaped upon sonication of a
mixture of a buffered aqueous phase, which contains the water-
soluble molecules to be encapsulated into the liposomes and an
organic phase in which the amphiphilic molecules are solubilized.
• The slow elimination of the organic solvent leads to the
conversion of these inverted micelles into viscous state and gel
form.
• At a critical point in this process, the gel state collapses, and some
of the inverted micelles were disturbed. The excess of
phospholipids in the environment donates to the formation of a
complete bilayer around the residual micelles, which results in
the creation of liposomes.
21. Detergent removal method:Detergent removal method:
Dialysis:
• The detergents at their critical micelle concentrations (CMC)
have been used to solubilize lipids.
• As the detergent is detached, the micelles become increasingly
better-off in phospholipid and lastly combine to form LUVs.
• The detergents were removed by dialysis.
• A commercial device called LipoPrep (Diachema AG,
Switzerland), which is a version of dialysis system, is obtainable
for the elimination of detergents.
• The dialysis can be performed in dialysis bags engrossed in large
detergent free buffers (equilibrium dialysis)
22. Detergent (cholate, alkyl glycoside, Triton X-100) removal of
mixed micelles (absorption):
• Detergent absorption is attained by shaking mixed micelle
solution with beaded organic polystyrene adsorbers such as
XAD-2 beads (SERVA Electrophoresis GmbH, Heidelberg,
Germany) and Bio-beads SM2 (Bio-Rad Laboratories, Inc.,
Hercules, USA).
• The great benefit of using detergent adsorbers is that they can
eliminate detergents with a very low CMC, which are not
entirely depleted.
23. Gel-permeation chromatography:-
• In this method, the detergent is depleted by size special
chromatography.
• Sephadex G-50, Sephadex G-l 00 (Sigma-Aldrich, MO, USA),
Sepharose 2B-6B, and Sephacryl S200-S1000 (General Electric
Company, Tehran, Iran) can be used for gel filtration.
• The liposomes do not penetrate into the pores of the beads
packed in a column. They percolate through the inter-bead
spaces. At slow flow rates, the separation of liposomes from
detergent monomers is very good.
• The swollen polysaccharide beads adsorb substantial amounts of
amphiphilic lipids; therefore, pretreatment is necessary.
• The pre-treatment is done by pre-saturation of the gel filtration
column by lipids using empty liposome suspensions.
24. Dilution:-
• Upon dilution of aqueous mixed micellar solution of detergent
and phospholipids with buffer, the micellar size and the
polydispersity increase fundamentally, and as the system is
diluted beyond the mixed micellar phase boundary, a
spontaneous transition from poly-dispersed micelles to
vesicles occurs.
25. Stealth liposomes and conventional liposomes:-
• Although liposomes are like biomembranes, they are still foreign
objects of the body. Therefore, liposomes are known by the
mononuclear phagocytic system (MPS) after contact with plasma
proteins. Accordingly, liposomes are cleared from the blood
stream.
• These stability difficulties are solved through the use of synthetic
phospholipids, particle coated with amphipathic polyethylene
glycol, coating liposomes with chitin derivatives, freeze drying,
polymerization, micro-encapsulation of gangliosides.
• Coating liposomes with PEG reduces the percentage of uptake by
macrophages and leads to a prolonged presence of liposomes in
the circulation and, therefore, make available abundant time for
these liposomes to leak from the circulation through leaky
endothelium.
26. • A stealth liposome is a sphere-shaped vesicle with a membrane
composed of phospholipid bilayer used to deliver drugs or genetic
material into a cell.
• A liposome can be composed of naturally derived phospholipids
with mixed lipid chains coated or steadied by polymers of PEG and
colloidal in nature.
• Stealth liposomes are attained and grown in new drug delivery
and in controlled release.
• This stealth principle has been used to develop the successful
doxorubicin-loaded liposome product that is presently marketed
as Doxil (Janssen Biotech, Inc., Horsham, USA) or Caelyx (Schering-
Plough Corporation, Kenilworth, USA) for the treatment of solid
tumors.
• Recently impressive therapeutic improvements were described
with the useof corticosteroidloaded liposome in experimental
arthritic models.
27. Mechanism of Liposome Formation:Mechanism of Liposome Formation:
• The basic part of liposome is formed by phospholipids, which are
amphiphilic molecules (having a hydrophilic head and
hydrophobic tail).
• The hydrophilic part is mainly phosphoric acid bound to a water
soluble molecule, whereas, the hydrophobic part consists of two
fatty acid chains with 10 – 24 carbon atoms and 0 – 6 double
bonds in each chain.
• When these phospholipids are dispersed in aqueous medium,
they form lamellar sheets by organizing in such a way that, the
polar head group faces outwards to the aqueous region while the
fatty acid groups face each other and finally form spherical/
vesicle like structures called as liposomes.
• The polar portion remains in contact with aqueous region along
with shielding of the non-polar part (which is oriented at an angle
to the membrane surface).
28. • When phospholipids are hydrated in water, along with the input
of energy like sonication, shaking, heating, homogenization, etc.
• It is the hydrophilic/ hydrophobic interactions between lipid –
lipid, lipid – water molecules that lead to the formation of
bilayered vesicles in order to achieve a thermodynamic
equilibrium in the aqueous phase.
• The reasons for bilayered formation include:
– The unfavorable interactions created between hydrophilic and
hydrophobic phase can be minimized by folding into closed
concentric vesicles.
– Large bilayered vesicle formation promotes the reduction of
large free energy difference present between the hydrophilic
and hydrophobic environment.
– Maximum stability to supramolecular self assembled structure
can be attained by forming into vesicles.
29. Evaluation of Liposomes:Evaluation of Liposomes:
• The characterization parameters for purpose of evaluation could
be classified into three broad Categories, which include physical,
chemical and biological parameters.
• Physical characterization evaluates various parameters including
size, shape, surface features, lamellarity phase-behaviour and drug
release profile.
• Chemical characterization includes those studies which establish
the purity and potency of various lipophillic constituents.
• Biological characterization parameters are helpful in establishing
the safety and suitability of formulation for therapeutic
application.
30. Size and size distribution:-
• When liposomes are intended for inhalation or parenteral
administration, the size distribution is of primary consideration,
since it influences the in vivo fate of liposomes along with the
encapsulated drug molecules.
• Various techniques of determining the size of the vesicles include
– microscopy (optical microscopy, negative stain transmission
electron microscopy, cryo-transmission electron microscopy,
freeze fracture electron microscopy and scanning electron
microscopy
– diffraction and scattering techniques (laser light scattering and
photon correlation spectroscopy) and
– hydrodynamic techniques (field flow fractionation, gel
permeation and ultracentrifugation).
31. Percent drug encapsulation:-
• The amount of drug encapsulated/ entrapped in liposome vesicle
is given by percent drug encapsulation.
• Column chromatography can be used to estimate the percent
drug encapsulation of liposomes.
• The formulation consists of both free (un-encapsulated) and
encapsulated drug. So as to know the exact amount of drug
encapsulated, the free drug is separated from the encapsulated
one.
• Then the fraction of liposomes containing the encapsulated drug
is treated with a detergent, so as to attain lysis, which leads to the
discharge of the drug from the vesicles into the surrounding
medium.
• This exposed drug is assayed by a suitable technique which gives
the percent drug encapsulated from which encapsulation
efficiency can be calculated.
32. • Trapped volume per lipid weight can also give the percent drug
encapsulated in a liposome vesicle. It is generally expressed as
aqueous volume entrapped per unit quantity of lipid, µl/µmol or
µg/mg of total lipid.
• In order to determine the trapped volume, various materials like
radioactive markers, fluorescent markers and spectroscopically
inert fluid can be used.
• Radioactive method is mostly used for determining trapped
volume. It is determined by dispersing lipid in an aqueous
medium containing a non-permeable radioactive solute like
[22Na] or [14C] inulin.
• Alternatively, water soluble markers like 6-carboxyfluorescein,
14C or 3H-glucose or sucrose can be used to determine the
trapped volume
33. Surface charge:-
• Since the charge on the liposome surface plays a key role in the in vivo
disposition, it is essential to know the surface charge on the vesicle
surface.
• Two methods namely, free-flow electrophoresis and zeta potential
measurement can be used to estimate the surface charge of the vesicle.
• The surface charge can be calculated by estimating the mobility of the
liposomal dispersion in a suitable buffer (determined using Helmholtz–
Smolochowski equation).
Vesicle shape and lamellarity:-
• Various electron microscopic techniques can be used to assess the shape
of the vesicles. The number of bilayers present in the liposome, i.e.,
lamellarity can be determined using freeze fracture electron microscopy
and 31P-Nuclear magnetic resonance analysis.
• Apart from knowing the shape and lamellarity, the surface morphology
of liposomes can be assessed using freeze-fracture and freeze-etch
electron microscopy.
34. Phospholipid identification and assay:-
• The chemical components of liposomes must be analyzed prior to
and after the preparation.
• Barlett assay, Stewart assay and thin layer chromatography can be
used to estimate the phospholipid concentration in the liposomal
formulation.
• A spectrophotometric method to quantify total phosphorous in a
sample was given in literature, which measure the intensity of
blue color developed at 825 nm against water.
• Cholesterol oxidase assay or ferric perchlorate method and Gas
liquid chromatography techniques can be used to determine the
cholesterol concentration.
35. Stability of Liposomes:-
• During the development of liposomal drug products, the stability
of the developed formulation is of major consideration.
• The therapeutic activity of the drug is governed by the stability of
the liposomes right from the manufacturing steps to storage to
delivery.
• A stable dosage forms is the one which maintains the physical
stability and chemical integrity of the active molecule during its
developmental procedure and storage.
• A well designed stability study includes the evaluation of its
physical, chemical and microbial parameters along with the
assurance of product’s integrity throughout its storage period.
• Hence a stability protocol is essential to study the physical and
chemical integrity of the drug product in its storage.