This document discusses modified release drug delivery systems (MRDDS), including extended release, delayed release, and targeted release dosage forms. It defines MRDDS as systems that control the time and location of drug release to accomplish therapeutic objectives. The document outlines the rationale for controlled drug delivery systems (CDDS), their advantages and disadvantages, criteria for selecting drug candidates, and important physiological and biological properties to consider for CDDS.
Controlled release drug delivery system2Bansari Patel
This document provides an overview of controlled release drug delivery systems (CRDDS). It defines CRDDS as systems that provide some control over the temporal or spatial release of drugs. The key advantages of CRDDS are maintaining effective drug levels, decreasing dosing frequency and side effects, and improving patient compliance. Factors like drug properties, pharmacokinetics, and pharmacodynamics can affect CRDDS. Various approaches to designing CRDDS are discussed.
This document provides an overview of gastric retention drug delivery systems (GRDDS). It discusses the need for and advantages of GRDDS. The key approaches covered for achieving gastric retention include floating drug delivery systems, mucoadhesive systems, swellable systems, and high density systems. The document reviews gastrointestinal physiology and factors affecting gastric emptying. It also evaluates different GRDDS approaches and provides examples of commercial gastroretentive formulations. In conclusion, the document states that GRDDS are preferable for delivering drugs that need to be released in the gastric region.
The document discusses bioadhesion and mucoadhesion. It defines bioadhesion as materials adhering to biological tissues for extended periods via interfacial forces. Mucoadhesion specifically refers to adhesion between materials and mucosal surfaces. Mucoadhesive drug delivery systems can prolong drug release at application sites, improving therapeutic outcomes. Ideal mucoadhesive polymers rapidly adhere to mucosal layers without interfering with drug release, are biodegradable and non-toxic, and enhance drug penetration at delivery sites. The mechanisms of bioadhesion involve wetting, swelling, interpenetration and entanglement of polymer chains followed by secondary bonding formations. Key factors influencing bioadhesion are discussed.
Powerpoint presentation on controlled drug delivery system. Its introduction, terminologies, rationale, advantages, disadvantages, selection of drug, approaches for designing controlled release formulations and physicochemical and biological properties of drug
Gastroretentive drug delivery system by mali vvVidhyaMali1
This document provides an overview of gastro-retentive drug delivery systems (GRDDS). It defines GRDDS as a drug delivery system that can retain a dosage form in the stomach for an extended period of time to slowly release medication. The document discusses the anatomy of the stomach and factors controlling gastric retention. It also outlines several approaches for GRDDS, including floating drug delivery systems, bioadhesive/mucoadhesive systems, and expandable/swellable systems. The advantages and applications of GRDDS are noted.
This presentation includes introduction, physiology of GIT, factors affecting GRDDS, Advantages and disadvantages, approaches to GRDDS and their mechanism, some of the marketed products using GRDDS mechanism.
Polymers are large molecules composed of repeating structural units and can be either natural or synthetic, biodegradable or non-biodegradable. They are widely used in controlled release drug delivery systems due to their ability to control drug release rates and provide advantages like improved patient compliance. Common polymers used include natural ones like collagen and alginate as well as synthetic biodegradable polymers like PLGA. Applications include ocular inserts and transdermal patches that use polymers to regulate drug diffusion out of a matrix over time.
This document provides an overview of transdermal drug delivery systems (TDDS). It discusses how TDDS work by delivering drugs through the skin for systemic effects at predetermined rates. The key advantages of TDDS include avoiding first-pass metabolism, providing long-lasting drug levels comparable to IV infusion, and allowing easy termination of drug delivery. The document outlines the anatomy and physiology of the skin, drug permeation through skin, and factors affecting permeation. It also describes various TDDS classifications, components, evaluation methods, applications, and some marketed TDDS products.
Controlled release drug delivery system2Bansari Patel
This document provides an overview of controlled release drug delivery systems (CRDDS). It defines CRDDS as systems that provide some control over the temporal or spatial release of drugs. The key advantages of CRDDS are maintaining effective drug levels, decreasing dosing frequency and side effects, and improving patient compliance. Factors like drug properties, pharmacokinetics, and pharmacodynamics can affect CRDDS. Various approaches to designing CRDDS are discussed.
This document provides an overview of gastric retention drug delivery systems (GRDDS). It discusses the need for and advantages of GRDDS. The key approaches covered for achieving gastric retention include floating drug delivery systems, mucoadhesive systems, swellable systems, and high density systems. The document reviews gastrointestinal physiology and factors affecting gastric emptying. It also evaluates different GRDDS approaches and provides examples of commercial gastroretentive formulations. In conclusion, the document states that GRDDS are preferable for delivering drugs that need to be released in the gastric region.
The document discusses bioadhesion and mucoadhesion. It defines bioadhesion as materials adhering to biological tissues for extended periods via interfacial forces. Mucoadhesion specifically refers to adhesion between materials and mucosal surfaces. Mucoadhesive drug delivery systems can prolong drug release at application sites, improving therapeutic outcomes. Ideal mucoadhesive polymers rapidly adhere to mucosal layers without interfering with drug release, are biodegradable and non-toxic, and enhance drug penetration at delivery sites. The mechanisms of bioadhesion involve wetting, swelling, interpenetration and entanglement of polymer chains followed by secondary bonding formations. Key factors influencing bioadhesion are discussed.
Powerpoint presentation on controlled drug delivery system. Its introduction, terminologies, rationale, advantages, disadvantages, selection of drug, approaches for designing controlled release formulations and physicochemical and biological properties of drug
Gastroretentive drug delivery system by mali vvVidhyaMali1
This document provides an overview of gastro-retentive drug delivery systems (GRDDS). It defines GRDDS as a drug delivery system that can retain a dosage form in the stomach for an extended period of time to slowly release medication. The document discusses the anatomy of the stomach and factors controlling gastric retention. It also outlines several approaches for GRDDS, including floating drug delivery systems, bioadhesive/mucoadhesive systems, and expandable/swellable systems. The advantages and applications of GRDDS are noted.
This presentation includes introduction, physiology of GIT, factors affecting GRDDS, Advantages and disadvantages, approaches to GRDDS and their mechanism, some of the marketed products using GRDDS mechanism.
Polymers are large molecules composed of repeating structural units and can be either natural or synthetic, biodegradable or non-biodegradable. They are widely used in controlled release drug delivery systems due to their ability to control drug release rates and provide advantages like improved patient compliance. Common polymers used include natural ones like collagen and alginate as well as synthetic biodegradable polymers like PLGA. Applications include ocular inserts and transdermal patches that use polymers to regulate drug diffusion out of a matrix over time.
This document provides an overview of transdermal drug delivery systems (TDDS). It discusses how TDDS work by delivering drugs through the skin for systemic effects at predetermined rates. The key advantages of TDDS include avoiding first-pass metabolism, providing long-lasting drug levels comparable to IV infusion, and allowing easy termination of drug delivery. The document outlines the anatomy and physiology of the skin, drug permeation through skin, and factors affecting permeation. It also describes various TDDS classifications, components, evaluation methods, applications, and some marketed TDDS products.
This document discusses gastroretentive drug delivery systems (GRDDS), which are oral dosage forms designed to remain in the stomach for an extended period of time to prolong drug release. It covers the rationale for using GRDDS, factors controlling gastric residence time, and various approaches for prolonging gastric retention including floating systems, high-density systems, and bioadhesive or magnetic systems. Floating systems include non-effervescent and effervescent types that float due to low density or gas generation. High-density systems do not float but remain in the stomach through bioadhesion, magnetic forces, swelling to a large size, or raft formation on gastric fluids.
Mucoadhesive drug delivery systems aim to increase drug bioavailability by keeping formulations in close contact with mucus membranes. There are three main stages of mucoadhesion: wetting and swelling, interpenetration of polymer chains with the mucus layer, and formation of chemical bonds. Several theories explain mucoadhesion, including electronic, adsorption, wetting, diffusion, and fracture theories. Key factors affecting mucoadhesion are related to the polymer properties, such as molecular weight, concentration, flexibility, and spatial conformation, as well as environmental and physiological factors. Mucoadhesive systems can provide benefits like prolonged drug residence at the site of action and increased drug absorption.
The document discusses osmotic drug delivery systems. It defines osmosis and osmotic pressure, and describes the basic components of osmotic drug delivery systems including semipermeable membranes, osmogens, and drug formulations. It classifies osmotic systems as implantable or oral, and describes several types of oral osmotic pumps including elementary, modified, multi-chamber, controlled porosity, and monolithic systems. Key factors that affect drug release are also outlined. The document concludes by listing several marketed osmotic products.
Factors affecting design of Controlled Release Drug Delivery Systems (write-up)Suraj Choudhary
This document discusses factors affecting the design of controlled release drug delivery systems (CRDDS). It outlines several key considerations including selection of the drug candidate based on properties like solubility and half-life. It also discusses medical rationales like dosing frequency and patient compliance. Biological factors that influence absorption, distribution, and elimination are examined. Physicochemical properties of the drug like solubility, molecular size, and ionization must also be considered. The document provides an in-depth overview of factors involved in developing an effective CRDDS formulation.
This document provides an overview of osmotically controlled drug delivery systems. It discusses the principles of osmosis that these systems utilize. Key components include a drug, osmotic agent, and semipermeable membrane. Factors that can affect the drug release rate include drug solubility, osmotic pressure, membrane characteristics, and orifice size. Various types of osmotic pumps are classified and described, including oral and implantable versions. Commercial applications and evaluation methods are also mentioned.
The device which is used in the intrauterine drug delivery system is known as an Intrauterine device (IUD) (2). IUDs or intrauterine devices are small artificial objects or devices inserted into the uterus to prevent the occurrence of pregnancy by disrupting the fertilization process as a result of sexual intercourse. They have gained popularity in recent times and are one of the most effective methods of birth control in terms of long-term contraception. It can be easily installed and is flexible. These devices are usually small in size and inserted through the cervix. IUDs reduce the need for abortion with unwanted pregnancies by preventing the effective movement of eggs and sperm. However, it cannot confirm the spread of STIs or STDs such as HIV, gonorrhoea, etc
Topics covered
Introduction
Advantages
Disadvantages
Development of intra uterine devices (IUDs)
Applications
References
This document discusses gastroretentive drug delivery systems. It begins by introducing the challenges of limited gastric residence time and rapid gastrointestinal transit for oral drug delivery. It then describes how gastroretentive delivery systems aim to retain the dosage form in the stomach to allow for controlled release of drugs that are absorbed in the upper GI tract. The document outlines various approaches to gastroretentive delivery including floating, gastroadhesive, high-density, and inflatable systems. It notes advantages like increased bioavailability and compliance through reduced dosing, as well as applications for drugs with absorption windows in the upper GI tract.
This document discusses mucoadhesive drug delivery systems (MDDS). It begins by defining MDDS as drug delivery systems that interact with mucus layers and increase drug residence time at absorption sites. It then discusses various types of MDDS (buccal, sublingual, etc.), advantages like prolonged drug effects, and challenges like irritation. The document also covers mucoadhesion theories, drug transport mechanisms, formulation considerations, and provides an example case study on salbutamol sulfate buccal patches.
Mucoadhesive drug delivery system Mali vv pptVidhyaMali1
This document discusses mucoadhesive drug delivery systems (MDDS). It begins by defining MDDS as systems that use the bioadhesive properties of certain polymers to target and prolong the release of drugs at mucous membranes. It then covers the basics of mucous membranes and their structure, composition, and functions. The document discusses the need for MDDS to enhance drug absorption, prolong drug residence time, and target drug delivery. It also outlines the advantages and disadvantages of MDDS, various routes of administration, mechanisms of mucoadhesion, theories of mucoadhesion, mucoadhesive polymers, and methods of evaluating MDDS. In the end, it provides some applications of MDDS such as vaccine delivery, cancer
Transdermal Drug Delivery System [TDDS]Sagar Savale
Management of illness through medication has entered an era of rapid growth. A variety of means by which drugs are delivered to the human body for the therapy such as tablets, capsules, injections, aerosols, creams, ointments, suppositories, liquids etc. are referred as a conventional drug formulations. Among many pharmaceutical dosage forms, continuous intravenous infusion at preprogrammed rate has been recognized as a superior mode of drug delivery. At present, the most common form of delivery of drugs is the oral route. It has the notable advantage of easy administration.
The document provides information on nasopulmonary drug delivery systems including nasal drug delivery and pulmonary drug delivery. It discusses the anatomy and physiology of the nasal cavity and respiratory tract. It also describes various formulation approaches for nasal delivery such as nasal gels, drops, sprays and powders. The document further explains dry powder inhalers, metered dose inhalers and nebulizers as pulmonary drug delivery systems along with their advantages and disadvantages. It also discusses some marketed products for nasal sprays, dry powder inhalers and metered dose inhalers.
Application Of Polymer In Controlled Release FormulationAnindya Jana
Polymers are becoming increasingly important in the field of drug delivery. The pharmaceutical applications of polymers range from their use as binders in tablets to viscosity and flow controlling agents in liquids, suspensions and emulsions. Polymers can be used as film coatings to disguise the unpleasant taste of a drug, to enhance drug stability and to modify drug release characteristics.
As a consequence, increasing attention has been focused on methods of giving drugs continually for a prolonged time periods and in a controlled fashion.
This technology now spans many fields and includes pharmaceutical, food and agricultural applications, pesticides, cosmetics, and household products.
ODDS (Ocular Drug Delivery Systems) provide novel approaches for instilling drugs onto the eye's surface or inside the eye. Common ODDS include gels, ointments, microspheres, and nanoparticles, and they offer benefits like increased dosing accuracy, sustained drug release, and improved ocular bioavailability. However, they also present disadvantages such as inability to stop treatment during emergencies and potential interference with vision. The eye has multiple barriers that limit drug penetration, including the tear film, cornea, conjunctiva, sclera, and blood-retinal barrier. Physical methods like iontophoresis, sonophoresis, and microneedles can enhance drug transport across these barriers. A
Factors affecting sustained release drug delivery system.Kavya S
contented and precise , Drug delivery system , sustained release preparation.factors like absorption, distribution ,metabolism , therapeutic window , absorption window.
This document discusses methods of formulating and evaluating buccal drug delivery systems. It describes the basic structure and designs of buccal dosage forms as being matrix or reservoir types. The key components are outlined as the drug substance, bioadhesive polymers, backing membrane, and permeation enhancers. Various formulation methods are provided for solid, semi-solid and liquid buccal dosage forms including tablets, patches, films, gels and sprays. Evaluation methods are also summarized such as weight variation, thickness, friability, hardness, and in-vitro swelling studies.
This document discusses implantable drug delivery systems. It describes how implantable pellets or capsules can continuously release drugs over long periods of time to treat conditions without frequent injections or hospital visits. Ideal properties of implants include biocompatibility and controlled drug release. Various types of implants are described, including biodegradable polymer matrices and osmotic pumps, which use osmotic pressure to precisely deliver drugs. Applications include cancer treatment and osteoporosis. Advantages are continuous dosing and patient compliance, while disadvantages include need for minor surgery and inability to easily stop therapy.
Introduction to CR/SR preparations, concept of controlled release formulation, challenges of CR drug delivery system, advantages and disadvantages, Factors influencing the design and performance of CR products (physiochemical properties: molecular size and diffusivity, aqueous solubility, ionization constant, partition coefficient, stability, pharmacokinetic and pharmacodynamic considerations: release rate and dose, Biological factors: Absorption, distribution, metabolism and elimination half life, therapeutic index, duration of action.
Kinetics of drug release from CRDS: Zero order, first order, Hixson-Crowell Release Model, Higuchi Release Model and Korsmeyer-Peppas Release Model
Oral controlled release systems: Dissolution controlled release (Matrix and encapsulated dissolution), diffusion controlled release (Reservoir and matrix system), dissolution and diffusion controlled release, Osmotically controlled release, pH independent formulations, Ion exchange resins.
Evaluation of CR formulations: Quality control methods( Identity, purity, strength, stability of the dosage form and drug in the dosage form, disintegration and dissolution, dosage form appearance, bioavailability of the drug from dosage form
This document discusses gastroretentive drug delivery systems (GRDDS), which are oral dosage forms designed to remain in the stomach for an extended period of time to prolong drug release. It covers the rationale for using GRDDS, factors controlling gastric residence time, and various approaches for prolonging gastric retention including floating systems, high-density systems, and bioadhesive or magnetic systems. Floating systems include non-effervescent and effervescent types that float due to low density or gas generation. High-density systems do not float but remain in the stomach through bioadhesion, magnetic forces, swelling to a large size, or raft formation on gastric fluids.
Mucoadhesive drug delivery systems aim to increase drug bioavailability by keeping formulations in close contact with mucus membranes. There are three main stages of mucoadhesion: wetting and swelling, interpenetration of polymer chains with the mucus layer, and formation of chemical bonds. Several theories explain mucoadhesion, including electronic, adsorption, wetting, diffusion, and fracture theories. Key factors affecting mucoadhesion are related to the polymer properties, such as molecular weight, concentration, flexibility, and spatial conformation, as well as environmental and physiological factors. Mucoadhesive systems can provide benefits like prolonged drug residence at the site of action and increased drug absorption.
The document discusses osmotic drug delivery systems. It defines osmosis and osmotic pressure, and describes the basic components of osmotic drug delivery systems including semipermeable membranes, osmogens, and drug formulations. It classifies osmotic systems as implantable or oral, and describes several types of oral osmotic pumps including elementary, modified, multi-chamber, controlled porosity, and monolithic systems. Key factors that affect drug release are also outlined. The document concludes by listing several marketed osmotic products.
Factors affecting design of Controlled Release Drug Delivery Systems (write-up)Suraj Choudhary
This document discusses factors affecting the design of controlled release drug delivery systems (CRDDS). It outlines several key considerations including selection of the drug candidate based on properties like solubility and half-life. It also discusses medical rationales like dosing frequency and patient compliance. Biological factors that influence absorption, distribution, and elimination are examined. Physicochemical properties of the drug like solubility, molecular size, and ionization must also be considered. The document provides an in-depth overview of factors involved in developing an effective CRDDS formulation.
This document provides an overview of osmotically controlled drug delivery systems. It discusses the principles of osmosis that these systems utilize. Key components include a drug, osmotic agent, and semipermeable membrane. Factors that can affect the drug release rate include drug solubility, osmotic pressure, membrane characteristics, and orifice size. Various types of osmotic pumps are classified and described, including oral and implantable versions. Commercial applications and evaluation methods are also mentioned.
The device which is used in the intrauterine drug delivery system is known as an Intrauterine device (IUD) (2). IUDs or intrauterine devices are small artificial objects or devices inserted into the uterus to prevent the occurrence of pregnancy by disrupting the fertilization process as a result of sexual intercourse. They have gained popularity in recent times and are one of the most effective methods of birth control in terms of long-term contraception. It can be easily installed and is flexible. These devices are usually small in size and inserted through the cervix. IUDs reduce the need for abortion with unwanted pregnancies by preventing the effective movement of eggs and sperm. However, it cannot confirm the spread of STIs or STDs such as HIV, gonorrhoea, etc
Topics covered
Introduction
Advantages
Disadvantages
Development of intra uterine devices (IUDs)
Applications
References
This document discusses gastroretentive drug delivery systems. It begins by introducing the challenges of limited gastric residence time and rapid gastrointestinal transit for oral drug delivery. It then describes how gastroretentive delivery systems aim to retain the dosage form in the stomach to allow for controlled release of drugs that are absorbed in the upper GI tract. The document outlines various approaches to gastroretentive delivery including floating, gastroadhesive, high-density, and inflatable systems. It notes advantages like increased bioavailability and compliance through reduced dosing, as well as applications for drugs with absorption windows in the upper GI tract.
This document discusses mucoadhesive drug delivery systems (MDDS). It begins by defining MDDS as drug delivery systems that interact with mucus layers and increase drug residence time at absorption sites. It then discusses various types of MDDS (buccal, sublingual, etc.), advantages like prolonged drug effects, and challenges like irritation. The document also covers mucoadhesion theories, drug transport mechanisms, formulation considerations, and provides an example case study on salbutamol sulfate buccal patches.
Mucoadhesive drug delivery system Mali vv pptVidhyaMali1
This document discusses mucoadhesive drug delivery systems (MDDS). It begins by defining MDDS as systems that use the bioadhesive properties of certain polymers to target and prolong the release of drugs at mucous membranes. It then covers the basics of mucous membranes and their structure, composition, and functions. The document discusses the need for MDDS to enhance drug absorption, prolong drug residence time, and target drug delivery. It also outlines the advantages and disadvantages of MDDS, various routes of administration, mechanisms of mucoadhesion, theories of mucoadhesion, mucoadhesive polymers, and methods of evaluating MDDS. In the end, it provides some applications of MDDS such as vaccine delivery, cancer
Transdermal Drug Delivery System [TDDS]Sagar Savale
Management of illness through medication has entered an era of rapid growth. A variety of means by which drugs are delivered to the human body for the therapy such as tablets, capsules, injections, aerosols, creams, ointments, suppositories, liquids etc. are referred as a conventional drug formulations. Among many pharmaceutical dosage forms, continuous intravenous infusion at preprogrammed rate has been recognized as a superior mode of drug delivery. At present, the most common form of delivery of drugs is the oral route. It has the notable advantage of easy administration.
The document provides information on nasopulmonary drug delivery systems including nasal drug delivery and pulmonary drug delivery. It discusses the anatomy and physiology of the nasal cavity and respiratory tract. It also describes various formulation approaches for nasal delivery such as nasal gels, drops, sprays and powders. The document further explains dry powder inhalers, metered dose inhalers and nebulizers as pulmonary drug delivery systems along with their advantages and disadvantages. It also discusses some marketed products for nasal sprays, dry powder inhalers and metered dose inhalers.
Application Of Polymer In Controlled Release FormulationAnindya Jana
Polymers are becoming increasingly important in the field of drug delivery. The pharmaceutical applications of polymers range from their use as binders in tablets to viscosity and flow controlling agents in liquids, suspensions and emulsions. Polymers can be used as film coatings to disguise the unpleasant taste of a drug, to enhance drug stability and to modify drug release characteristics.
As a consequence, increasing attention has been focused on methods of giving drugs continually for a prolonged time periods and in a controlled fashion.
This technology now spans many fields and includes pharmaceutical, food and agricultural applications, pesticides, cosmetics, and household products.
ODDS (Ocular Drug Delivery Systems) provide novel approaches for instilling drugs onto the eye's surface or inside the eye. Common ODDS include gels, ointments, microspheres, and nanoparticles, and they offer benefits like increased dosing accuracy, sustained drug release, and improved ocular bioavailability. However, they also present disadvantages such as inability to stop treatment during emergencies and potential interference with vision. The eye has multiple barriers that limit drug penetration, including the tear film, cornea, conjunctiva, sclera, and blood-retinal barrier. Physical methods like iontophoresis, sonophoresis, and microneedles can enhance drug transport across these barriers. A
Factors affecting sustained release drug delivery system.Kavya S
contented and precise , Drug delivery system , sustained release preparation.factors like absorption, distribution ,metabolism , therapeutic window , absorption window.
This document discusses methods of formulating and evaluating buccal drug delivery systems. It describes the basic structure and designs of buccal dosage forms as being matrix or reservoir types. The key components are outlined as the drug substance, bioadhesive polymers, backing membrane, and permeation enhancers. Various formulation methods are provided for solid, semi-solid and liquid buccal dosage forms including tablets, patches, films, gels and sprays. Evaluation methods are also summarized such as weight variation, thickness, friability, hardness, and in-vitro swelling studies.
This document discusses implantable drug delivery systems. It describes how implantable pellets or capsules can continuously release drugs over long periods of time to treat conditions without frequent injections or hospital visits. Ideal properties of implants include biocompatibility and controlled drug release. Various types of implants are described, including biodegradable polymer matrices and osmotic pumps, which use osmotic pressure to precisely deliver drugs. Applications include cancer treatment and osteoporosis. Advantages are continuous dosing and patient compliance, while disadvantages include need for minor surgery and inability to easily stop therapy.
Introduction to CR/SR preparations, concept of controlled release formulation, challenges of CR drug delivery system, advantages and disadvantages, Factors influencing the design and performance of CR products (physiochemical properties: molecular size and diffusivity, aqueous solubility, ionization constant, partition coefficient, stability, pharmacokinetic and pharmacodynamic considerations: release rate and dose, Biological factors: Absorption, distribution, metabolism and elimination half life, therapeutic index, duration of action.
Kinetics of drug release from CRDS: Zero order, first order, Hixson-Crowell Release Model, Higuchi Release Model and Korsmeyer-Peppas Release Model
Oral controlled release systems: Dissolution controlled release (Matrix and encapsulated dissolution), diffusion controlled release (Reservoir and matrix system), dissolution and diffusion controlled release, Osmotically controlled release, pH independent formulations, Ion exchange resins.
Evaluation of CR formulations: Quality control methods( Identity, purity, strength, stability of the dosage form and drug in the dosage form, disintegration and dissolution, dosage form appearance, bioavailability of the drug from dosage form
Unit 7-Modified Release Dosage Forms.pptxmarakiwmame
This document discusses different types of drug delivery systems including immediate-release, modified-release, delayed-release, and extended-release systems. Immediate-release systems provide rapid drug absorption but require frequent dosing. Modified-release systems aim to control or prolong drug release for benefits like reduced dosing frequency and steady drug levels. Specific modified-release systems covered are delayed-release, which release drug only after a lag time, and extended-release, which release drug continuously over an extended period. Design considerations for modified-release systems include drug properties and pharmacokinetics.
Unit 7-Modified Release Dosage Forms.pptxmarakiwmame
This document discusses different types of drug delivery systems including immediate-release, modified-release, delayed-release, and extended-release systems. Immediate-release systems provide rapid drug absorption but require frequent dosing. Modified-release systems aim to control or prolong drug release over time for benefits like reduced dosing frequency and steady drug levels. Specific modified-release systems described include delayed-release, extended-release, and targeted-release formulations. Extended-release systems can reduce dosing frequency and fluctuations in drug concentrations. Key factors in designing modified drug delivery systems include drug properties and pharmacokinetics.
Unit 7-Modified Release Dosage Forms.pptxmarakiwmame
This document discusses different types of drug delivery systems including immediate-release, modified-release, delayed-release, and extended-release systems. Immediate-release systems provide rapid drug absorption but require frequent dosing. Modified-release systems aim to control or prolong drug release over time for benefits like reduced dosing frequency and steady drug levels. Specific modified-release systems described include delayed-release, extended-release, and targeted-release formulations.
Video Lecture is available at https://www.youtube.com/watch?v=DXu_CLgB4q0
Introduction, terminology/definitions and rationale, advantages, disadvantages, selection of drug candidates. Approaches to design-controlled release formulations based on diffusion, dissolution and ion exchange principles. Physicochemical and
biological properties of drugs relevant to controlled release formulations.
This document provides an overview of controlled drug delivery systems. It begins with introducing drug delivery systems and limitations of conventional dosage forms. It then discusses the objectives and ideal properties of controlled drug delivery. The document outlines the history, differences between sustained vs controlled release, advantages, disadvantages, and factors to consider in controlled release drug delivery system design. It also describes various mechanisms for formulating controlled release drug delivery systems including diffusion controlled, dissolution controlled, and osmotically controlled systems.
Fundamental concept of modified drug releaseAbhinayJha3
Different Terminologies used in a modified release
1. Sustained release
2. Delayed release
3. Prolonged release
4. Extended-release
5. Controlled release
6. Site-specific targeting and receptor targeting
SELECTION OF DRUG CANDIDATE FOR ORAL SUSTAINED RELEASE SYSTEMS, BIOPHARMACEUTICAL CLASSIFICATION SYSTEM.
Fundamental concept of modified drug releaseAbhinayJha3
BIOPHARMACEUTICAL CLASSIFICATION SYSTEM
Different Terminologies used in a modified release
1. Sustained release
2. Delayed release
3. Prolonged release
4. Extended-release
5. Controlled release
6. Site-specific targeting and receptor targeting
This document provides an overview of sustained release drug delivery systems. It discusses the basic concept, advantages, and mechanisms of sustained release formulations. Some key points include:
- Sustained release formulations aim to reduce dosing frequency and maintain therapeutic drug levels over an extended period through continuous drug release.
- Hydrophilic polymer matrices are commonly used to formulate sustained release dosage forms.
- Factors like drug solubility, stability, and absorption properties must be considered to determine if a drug is suitable for a sustained release system. The drug release rate from these systems is controlled by diffusion, dissolution, or osmotic pressure mechanisms.
This document discusses controlled drug delivery systems. It begins by defining controlled drug delivery systems and their goal of releasing therapeutic doses of a drug in the desired location and time period. It then discusses various types of modified release dosage forms like sustained release, extended release, and controlled release. The document covers advantages and disadvantages of these systems as well as factors influencing their design and performance. It provides examples of commercial modified release products and discusses approaches to designing controlled release formulations.
This document provides an overview of gastroretentive drug delivery systems (GR-DDS). GR-DDS are designed to prolong the gastric residence time of drugs to increase absorption in the upper gastrointestinal tract. The document discusses factors that influence gastric emptying and various approaches to increasing gastric retention time, including floating, swelling/expanding, mucoadhesive, magnetic, and high density systems. Key advantages of GR-DDS include prolonged drug release, increased bioavailability, and reduced drug fluctuations.
Formulation and evaluation of sustained release tablets of ambroxol hcl using...Venkatesh Pillala
This document provides an introduction and literature review for formulating and evaluating sustained release tablets of Ambroxol HCl using natural polymers. It discusses sustained release dosage forms, factors affecting oral sustained release dosage forms, parameters for drug selection, formulation methods, and mechanisms of drug release from matrix tablets. The literature review covers previous studies on formulating sustained release dosage forms for other drugs using natural polymers. The objective is stated as preparing and evaluating sustained release tablets of Ambroxol HCl to improve its oral bioavailability, reduce dosing frequency, and optimize polymer concentrations.
Sustained and Controlled Release Drug Delivery Systems MoidulIslam17
Sustained and controlled drug delivery systems provide drugs to the body over an extended period of time compared to conventional dosage forms. They help maintain constant drug levels in the bloodstream and slow drug release rates to prolong a drug's duration of action. Sustained release aims to slowly release drug over time after a single dose while controlled release maintains constant drug levels. Factors like a drug's solubility, stability, and pharmacokinetics influence the design of these systems. Common oral sustained/controlled release systems include matrix systems, reservoir systems, osmotic pressure systems, and pH dependent formulations. The presentation discusses various classification schemes and design considerations for developing sustained and controlled drug delivery.
Introduction, Definitions, Advantages and Disadvantages, Selection of drug candidates for designing controlled drug release systems and rationale biological and medical rationale
This document discusses sustained release oral dosage forms. It defines sustained release as achieving a steady blood or tissue level of a drug over an extended period of time. This is beneficial for drugs with short half-lives that require repeated dosing. The document outlines criteria for drugs to be formulated as sustained release, including desirable half-life and absorption characteristics. Advantages include improved patient compliance from less frequent dosing and better drug utilization. Matrix tablets are discussed as a common sustained release formulation where the drug is uniformly dispersed within a polymeric matrix to control release rate.
Sustained and Controlled Drug Delivery System.pptxHarshadaa bafna
This document provides information about sustained and controlled drug delivery systems. It begins with definitions of sustained release and controlled release, and discusses the advantages of maintaining consistent drug levels over time. It then covers topics like steady state concepts, diffusion mechanisms, dissolution models and polymer characterization as they relate to sustained and controlled release drug delivery. Evaluation methods for sustained release and controlled release tablets are also mentioned.
This document provides an introduction to sustained release and controlled release drug formulations. It defines sustained release as slowly releasing a drug over 8-12 hours, while controlled release delivers a drug at a predetermined rate for a specified time period. Some key advantages of these formulations are improved patient compliance, better drug utilization, and decreased side effects. Physicochemical drug properties like solubility, permeability and stability can impact whether a drug is suitable for these delivery systems. The document discusses various approaches for sustained and controlled release based on these physicochemical factors.
Factors Affecting Sustain Realease Drug delivery SystemAnam Sami
This document provides an overview of sustain release drug delivery systems and formulations. It discusses the advantages and disadvantages of SRDD systems as well as key factors that affect their formulation, including physiological factors like dose size, partition coefficient, aqueous solubility, drug stability, and protein binding. Biological factors like absorption, distribution, metabolism, and biological half-life are also reviewed. Different approaches for SRDD systems are mentioned, along with examples of specific approaches.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Phenomics assisted breeding in crop improvementIshaGoswami9
As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
and analysis methods, numerous infrastructure platforms have been developed for phenotyping.
Nucleophilic Addition of carbonyl compounds.pptxSSR02
Nucleophilic addition is the most important reaction of carbonyls. Not just aldehydes and ketones, but also carboxylic acid derivatives in general.
Carbonyls undergo addition reactions with a large range of nucleophiles.
Comparing the relative basicity of the nucleophile and the product is extremely helpful in determining how reversible the addition reaction is. Reactions with Grignards and hydrides are irreversible. Reactions with weak bases like halides and carboxylates generally don’t happen.
Electronic effects (inductive effects, electron donation) have a large impact on reactivity.
Large groups adjacent to the carbonyl will slow the rate of reaction.
Neutral nucleophiles can also add to carbonyls, although their additions are generally slower and more reversible. Acid catalysis is sometimes employed to increase the rate of addition.
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptxMAGOTI ERNEST
Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
hematic appreciation test is a psychological assessment tool used to measure an individual's appreciation and understanding of specific themes or topics. This test helps to evaluate an individual's ability to connect different ideas and concepts within a given theme, as well as their overall comprehension and interpretation skills. The results of the test can provide valuable insights into an individual's cognitive abilities, creativity, and critical thinking skills
1. By
Dr. Chinmaya Keshari Sahoo. M.Pharm, Ph.D
Associate Professor
College of Pharmaceutical Sciences, Puri
2. CONTENTS
1. Introduction
2. Modified Release Drug Delivery System (MRDDS)
3. Terminology/definitions
4. Rationale of CDDS
5. Advantages
6. Disadvantages
7. Selection of drug candidates
8. Physiological properties for CDDS
9. Biological properties for CDDS
2
3. INTRODUCTION
Conventional oral drug delivery system offers an
immediate release of the drug and cannot maintain
effective concentration at the target site for longer
period of time.
The bioavailability of drugs by conventional drug
delivery is less due to presence of food, pH of gastro
intestinal tract (GIT), degradation by enzymes of GI
fluid, change in GI motility etc.
Most conventional oral drug products result in drug
absorption problem and decline drug’s pharmacokinetic
profile.
For avoid these limitations modified release drug
delivery system has taken major role in the
pharmaceutical development.
3
4. Modified release drug delivery system
Modified release drug delivery system (MRDDS)
MRDDS is defined as one for which the drug release
characteristics of time course and location are chosen to
accomplish therapeutic or convenience objectives to
influence the release profile of a drug from its delivery
system.
Classification of MRDDS
MRDDS is classified into 3 types such as
1.Extended release dosage form
2.Delayed release dosage form
3.Targeted release dosage form
4
5. Contd.
1. Extended release dosage form (ERDF)
ERDF allows at least a twofold reduction in dosage
frequency as compared to that drug presented as an
immediate release (conventional) dosage form.
The dosage form releases the drug slower than normal
manner at predetermined rate.
The prolonged action drug product is designed to release
the drug slowly and to provide a continuous supply of
drug over an extended period.
ERDF includes sustained release, and controlled-
release dosage forms.
5
6. Contd.
Sustained release dosage forms
Sustained release system delivers an initial therapeutic
dose of the drug (loading dose) followed by slower and
constant release of drug.
Loading dose is an initial higher dose of a drug that
may be given at the beginning of a course of treatment
before dropping down to a lower mainteince dose.
These systems maintain the rate of drug release over a
sustained period.
Sustained-release dosage forms achieve this mostly by
the use of suitable polymers, which are used either to
coat granules or tablets (reservoir systems) or to form a
matrix in which the drug is dissolved or dispersed
(matrix systems).
6
7. Contd.
Controlled-release dosage forms
Controlled release dosage forms cover a wide range of
prolonged action formulations which provide
continuous release of their active ingredients at
predetermined rate and predetermined time.
There is maximum utilization of drug enabling
reduction in total amount of dose administered and
possibility of delivering drugs having short biological
half life.
The release kinetics is usually follow zero-order.
Controlled drug delivery system (CDDS) can improve
the therapeutic efficacy and safety of a drug by precise
temporal and spatial placement in the body thereby
reducing both the size and number of doses required.
7
8. Contd.
Temporal delivery of drug refers to controlling the rate
or specific time of drug delivery to the target tissue.
Spatial delivery of drugs relates to target a drug to a
specific organ or tissue.
8
9. Contd.
2. Delayed release dosage form (DRDF)
DRDF can be defined as systems which are formulated
to release the active ingredient at a time other than
immediately after administration.
DRDF can control where the drug is released, e.g.
when the dosage form reaches the small intestine
(enteric-coated dosage forms) or the colon (colon-
specific dosage forms).
3. Targeted release dosage forms
Targeted release dosage forms release drug at or near
the intended physiologic site of action.
It may have either immediate or extended release
characteristics.
9
11. Rationale of CDDS
The basic rationale of a CDDS is to optimize the
biopharmaceutics, pharmacokinetics (PK), and
pharmacodynamics (PD) properties of a drug in such a way that
its utility is maximized through reduction in side effects and cure
or control of disease condition in the shortest possible time by
using smallest quantity of drug, administered by most suitable
route.
Alter PK/PD by:
– Design of drug delivery system
– Modify drug structure
– Modify physiology
Duration of drug action is a design property of the rate
controlled dosage form and not a property of the drug molecule’s
inherent kinetic characteristics.
11
12. ADVANTAGES OF CDDS
1. The frequency of drug administration is reduced.
2. Patient compliance can be improved.
3. The drug administration is more convenient.
4. There is better control of drug absorption.
5. The total amount of drug administration can be reduced.
6. Safety margin of high potency drugs can be increased.
7. Treatment efficacy is improved.
8. Bioavailability of drugs is improved.
9. Reduction in health care cost by improved therapy and
shorter treatment period.
12
13. DISADVANTAGES OF CDDS
1. Poor in vitro – in vivo correlation is observed.
2.Possibility of dose dumping due to food, physiologic or
formulation variables or chewing or grinding of oral
formulations by the patient and thus, increased risk of
toxicity.
3. Retrieval of drug is difficult in case of toxicity, poisoning
or hypersensitivity reactions.
4. Increased cost of manufacturing.
5.More rapid development of tolerance and counseling.
13
14. SELECTION OF DRUG CANDIDATES
I. Biopharmaceutic Properties
Properties of drug Desired features
Molecular size Less than 600 D
Aqueous solubility More than 0.1 mg/ml
Partition coefficient (Ko/w) 1-2
Dissociation constant pKa Acidic drugs pKa ˃2.5,
Basic drugs pKa ˂11
Ionisation at physiological pH Not more than 95%
Stability in GI milieu Stable at both gastric and intestinal pH
Absorption mechanism Passive absorption
14
15. Contd.
II. Pharmacokinetic (PK) Properties
Properties of drug Desired features
Absorption rate constant (Ka) High
Elimination half life 2-6 h
Metabolism rate Not too high
Dosage form index 1
15
16. Contd.
III. Pharmacodynamic (PD) Properties
Properties of drug Desired features
Dose Maximum 1000 mg
Therapeutic range Wide
Therapeutic index Wide
PK/PD relation ship Good
16
17. PHYSIOCHEMICAL PROPERTIES OF DRUG FOR CDDS
1. Aqueous solubility of the drug
2. Partition coefficient (Ko/w)
3. Drug pKa and ionization at physiological pH
4. Drug stability
5. Molecular weight of drug and diffusivity
6.Dose size
7. Protein binding
17
18. CONTD.
1. Aqueous solubility of the drug
A drug with good aqueous solubility, especially if pH
independent, serves as a good candidates
Generally highly soluble drugs are undesirable for
formulation in a controlled release product and very
poorly soluble drugs are not suitable for controlled
release system.
Class III (High solubility-low permeability) and Class IV
(low solubility-low permeability) drugs are poor
candidate for controlled release dosage forms.
The drug with solubility <0.1 mg/ml create significant
solubilization problem (Lower limit).
18
19. CONTD
2. Partition coefficient (Ko/w)
Partition coefficient is defined as the fraction of drug in an
oil phase to that of an adjacent aqueous phase at
equilibrium.
Drugs with extremely high partition coefficient are very oil
soluble and penetrates in to various membranes very easily.
Greater the partition coefficient of a drug greater its
lipophilicity and thus greater is its rate and extent of
absorption.
High partition coefficient compound are predominantly lipid
soluble and have very low aqueous solubility and thus these
compound persist in the body for long periods.
Ko/w value between 1 -2 is suitable for CDDS
19
20. CONTD.
3. Drug pKa and ionization at physiological pH
Drugs existing largely in ionized form are poor
candidates for oral CDDS.
The pKa range for acidic drug whose ionization
is pH sensitive is around 3.0-7.5 and pKa range
for basic drug whose ionization is pH sensitive is
around 7.0-11.0 are ideal for optimum positive
absorption.
For optimum passive absorption the drugs
should be non ionized.
20
21. CONTD.
4. Drug stability
Drugs unstable in gastrointestinal environment
cannot be administered as oral controlled release
formulation because of bioavailability problems.
A different route can be selected if failed in one
route.
Drugs stable in stomach gets released in stomach
and which are unstable gets released in intestine.
Drugs may be protected from enzymatic degradation
by incorporation in to a polymeric matrix
21
22. CONTD
5. Molecular weight of drug and diffusivity
The ability of a drug to diffuse through
membranes is called diffusivity which is a
function of molecular weight.
Lower the molecular weight faster and more
complete absorption.
Drugs with large molecular size are poor
candidates for oral controlled drug delivery
system.
The upper limit of drug molecular size for
passive diffusion is 600 Daltons.
22
23. CONTD
6.Dose size
For those drugs requiring large conventional doses, the
volume of sustained dose may be too large to be
practical.
The compounds that require large dose are given in
multiple amounts or formulated into liquid systems.
The greater the dose size, greater the fluctuation.
So the dose should have proper size.
The upper limit of dose size is 1000 mg for CDDS.
23
24. CONTD.
7. Protein binding
Drug protein binding acts as depot for drug producing
prolonged release profile-high degree of binding occurs .
drugs + mucin= increases absorption
Charged compounds greater tendency to bind.
e.g. Diazepam and novobiocin- 95% protein binding
Extensive binding to plasma proteins –long half life of
elimination for drugs- most required property for a sustained
release.
24
25. BIOLOGICAL PROPERTIES OF DRUGS
1. Absorption
2. Distribution
3. Metabolism
4. Duration of action
5. Margin of safety
6. Role of disease state
25
27. CONTD.
1. Absorption
Ideal CRDDS should release the complete drug and the
released drug should be completely absorbed
Drugs with poor absorption –poor candidate for CDDS.
The fraction of drug absorbed from the system can be
lower than the expected due to:
-degradation of drug. Eg- Penicillin G
-site-specific, dose-dependent absorption,
-poor water solubility
-small partition coefficient.
27
28. CONTD.
2.Distribution
Distribution refers to the reversible transfer of drug from
one location to another inside the body.
Depends on affinity of drug to bind with plasma proteins
and ability of drug to pass through tissue membranes.
Apparent volume of distribution (Vd) is defined as the
hypothetical volume of body fluids to which a drug is
dissolved or distributed.
28
29. CONTD.
3.Metabolism
The drug which is extensively metabolized is suitable for
CDDS as long as the rate of metabolism is not too rapid.
The extent of metabolism should be identical and
predictable when the drug is administered by different
routes.
The drug which is capable of inducing or inhibiting
metabolism is a poor candidate for CDDS.
Drugs possessing variations in bioavailability due to
first-pass effect or intestinal metabolism are not suitable for
sustained/controlled drug delivery.
Elimination constant or appearance of metabolites –reflects
the Metabolism of a drug.
29
30. CONTD.
4.Duration of action
The usual goal – maintain therapeutic blood
levels to an extended period.
Rate of absorption= Rate of elimination
Half life of drug range between 2- 6 h.
Short half life dose size will increase for large
release if CDDS produced.
Long half lives more than 6h sustained effect is
already there.
30
31. CONTD.
5. Margin of Safety
Estimation of relative safety of drug by therapeutic index.
Therapeutic index(TI) = TD50/ED50
Where TD50 is toxic dose, ED50 is effective dose
Larger the ratio- safer the drug TI> 10
Decisions on the margin of safety is done based on the
combination with therapeutically safe and effective plasma
concentration.
31
32. CONTD.
6. Role of Disease state
Disease acts as a stimulus for the development of CDDS
Example: Rheumatoid arthritis- Aspirin
Biological half life- 6h
Aspirin sustained release preparation –prevents morning
stiffness.
It can be sustained upto 8-10 h
32