Gel is a solid, jelly-like material that can range from soft to tough. It consists of a network of solid molecules dispersed throughout a liquid. There are several types of gels including hydrogels, where water is the liquid, and organogels, where an organic liquid is used. Gels are used in many applications such as cosmetics, food, pharmaceuticals, tissue engineering and moisture retention in soil.
This document discusses polymer hydrogels and compares a diaper and Jell-O. It finds that the diaper absorbed more water than Jell-O and was a stronger hydrogel. Both absorbed water, but you can eat Jell-O and not diapers. The document defines terms like polymer, monomer, cross-linking, absorption, and hydrogel. It asks the reader to compare diapers and Jell-O, describe what a hydrogel does, think of other hydrogel examples or uses, and propose their own hydrogel purpose and design.
A hydrogel is a solid material that absorbs water and swells to form a network. It consists of polymer chains that are cross-linked to form a three-dimensional structure. When dry, the polymer chains are collapsed, but when placed in water, the chains hydrate and expand to create a gel-like swollen network. Common examples of hydrogels include the superabsorbent polymers used in diapers to absorb moisture and gelatin, which forms a solid gel when cooled from a liquid state due to the cross-linking of gelatin molecules.
Hydrogels are a group of hydrophilic polymeric materials that have the ability to swell but do not dissolve immediately.Hydrogels have gained attention in biomediacal applications and is gaining popularity in dental research .
A colloid is a mixture where one substance is dispersed evenly throughout another. Unlike solutions, colloidal particles are larger and do not completely dissolve. Colloids can be solid, liquid, or gaseous mixtures. Common examples include fog, milk, and blood. Colloidal particles scatter light and exhibit Brownian motion. They cannot be separated by filtration due to their small but suspended particle size.
Hydrogels are three-dimensional network of hydrophilic cross-linked polymer that do not dissolve but can swell in water or can respond to the fluctuations of the environmental stimuli
Hydrogels are highly absorbent (they can contain over 90% water) natural or synthetic polymeric networks
Hydrogels also possess a degree of flexibility very similar to natural tissue, due to their significant water content
UNIT 01/PART 01: BP 403T_PHYSICAL PHARMACEUTICS: INTRODUCTIONShailenderMohan2
This presentation deals with the Introduction of Colloidal Dispersion (Unit 1) of syllabus of AKTU, Lucknow and PCI, New Delhi. In this ppt I have discussed the basics of Colloidal Dispersion and how various factors helps in the dispersion formation or destruction.
The document discusses colloids and their classification. It defines colloids as substances that are microscopically dispersed through another substance, with particle sizes between 10-10000 Angstroms. Colloids are classified in several ways, including by particle size (molecular dispersion, colloidal dispersion, coarse dispersion), physical state of phases, type of dispersed particles (multimolecular, macromolecular), appearance (sols, gels), and electrical charge on particles (positive, negative). Common colloidal systems include sols, emulsions, foams and aerosols. Micelle formation in colloids and the critical micelle concentration are also explained.
This document discusses polymer hydrogels and compares a diaper and Jell-O. It finds that the diaper absorbed more water than Jell-O and was a stronger hydrogel. Both absorbed water, but you can eat Jell-O and not diapers. The document defines terms like polymer, monomer, cross-linking, absorption, and hydrogel. It asks the reader to compare diapers and Jell-O, describe what a hydrogel does, think of other hydrogel examples or uses, and propose their own hydrogel purpose and design.
A hydrogel is a solid material that absorbs water and swells to form a network. It consists of polymer chains that are cross-linked to form a three-dimensional structure. When dry, the polymer chains are collapsed, but when placed in water, the chains hydrate and expand to create a gel-like swollen network. Common examples of hydrogels include the superabsorbent polymers used in diapers to absorb moisture and gelatin, which forms a solid gel when cooled from a liquid state due to the cross-linking of gelatin molecules.
Hydrogels are a group of hydrophilic polymeric materials that have the ability to swell but do not dissolve immediately.Hydrogels have gained attention in biomediacal applications and is gaining popularity in dental research .
A colloid is a mixture where one substance is dispersed evenly throughout another. Unlike solutions, colloidal particles are larger and do not completely dissolve. Colloids can be solid, liquid, or gaseous mixtures. Common examples include fog, milk, and blood. Colloidal particles scatter light and exhibit Brownian motion. They cannot be separated by filtration due to their small but suspended particle size.
Hydrogels are three-dimensional network of hydrophilic cross-linked polymer that do not dissolve but can swell in water or can respond to the fluctuations of the environmental stimuli
Hydrogels are highly absorbent (they can contain over 90% water) natural or synthetic polymeric networks
Hydrogels also possess a degree of flexibility very similar to natural tissue, due to their significant water content
UNIT 01/PART 01: BP 403T_PHYSICAL PHARMACEUTICS: INTRODUCTIONShailenderMohan2
This presentation deals with the Introduction of Colloidal Dispersion (Unit 1) of syllabus of AKTU, Lucknow and PCI, New Delhi. In this ppt I have discussed the basics of Colloidal Dispersion and how various factors helps in the dispersion formation or destruction.
The document discusses colloids and their classification. It defines colloids as substances that are microscopically dispersed through another substance, with particle sizes between 10-10000 Angstroms. Colloids are classified in several ways, including by particle size (molecular dispersion, colloidal dispersion, coarse dispersion), physical state of phases, type of dispersed particles (multimolecular, macromolecular), appearance (sols, gels), and electrical charge on particles (positive, negative). Common colloidal systems include sols, emulsions, foams and aerosols. Micelle formation in colloids and the critical micelle concentration are also explained.
Suspension Formulation Overview For Formulators and Development ScientistsJim McElroy
This document discusses suspension formulations. Suspensions have a dispersed solid phase and a dispersion medium that can be solid, liquid, or gas. Particle interactions can be controlled through electrostatic or steric repulsive forces using formulation techniques. Forces like van der Waals attractions cannot be controlled. Structured vehicles use shear thinning polymers and clays to create suspensions that are semi-solid at rest but fluid with shaking, preventing settling. Flocculation uses electrolytes or polymers to reduce repulsive forces and promote particle aggregation and settling.
3rd Lecture on Adsorption and Colloids | Chemistry Part II | 11th StdAnsari Usama
This document provides information on catalysts and colloids. It defines a catalyst as a substance that increases the rate of a reaction without undergoing a permanent chemical change. It discusses important features of solid catalysts such as catalytic activity and selectivity. It then defines colloids as heterogeneous mixtures with particle sizes between 2-500nm and provides examples. It classifies colloids based on physical state, interaction between phases, and molecular size.
The document discusses the applications of colloids in everyday life. It explains that colloids are mixtures where one substance is dispersed evenly throughout another substance on a nano scale. Some key applications of colloids mentioned include using them in many foods like milk and bread, medicines that are more easily absorbed by the body, water purification by coagulation of impurities, sewage disposal by electrophoresis, and smoke precipitation using charged plates in a Cottrell precipitator. Colloids also play a role in processes like rubber production from latex, leather tanning, soap cleansing action, forming deltas where rivers meet oceans, and giving the sky its blue color.
The document discusses colloids, defining them as heterogeneous mixtures with dispersed particles between 1-100 nm. It classifies different types of colloids based on the state of the dispersed and continuous phases, such as emulsions, foams, sols, and gels. The document also examines the unique properties of colloids, including the Tyndall effect, Brownian motion, and their ability to adsorb other substances.
Colloids play an important role in the pharmaceutical industry. Colloids are mixtures where very small particles of one substance are evenly distributed throughout another. They can be classified based on the state of aggregation or interaction of the dispersed and continuous phases. Common colloidal systems used in medicine include eye lotions, sulphur for skin conditions, various metals as therapeutic agents, and plasma proteins. Colloids increase the solubility, stability, and bioavailability of drugs.
Nature of stability of Colloidal SystemsAyeesha Tarik
This document provides an overview of colloidal systems and their classification. It begins by defining colloids as mixtures where one substance is dispersed as minute particles throughout another substance. Colloids are classified based on the state of the dispersed and dispersion mediums, which can be solid, liquid or gas. This results in different types of colloids including sols, emulsions, gels and aerosols. The document also discusses factors that influence the stability of colloids such as electrical forces, interaction with the dispersion medium, and stabilization methods.
Hydrogels are cross-linked polymer networks that can absorb large amounts of water. They come in natural and synthetic varieties. Hydrogels can be classified based on their synthesis method (homopolymer, copolymer, multipolymer), structure (amorphous, semi-crystalline, hydrogen-bonded), or electric charge (non-ionic, ionic, amphoteric, zwitterionic). Hydrogels have properties like high absorption capacity and biodegradability. They have a wide range of applications including use in contact lenses, hygiene products, wound dressings, and drug delivery.
This document summarizes a seminar on colloidal dispersions presented by Sayani Saha. It defines colloidal dispersions as systems with a dispersed particle phase and continuous dispersion medium between 1-1000 nm. Dispersions are classified by size as molecular, colloidal, or coarse dispersions. The properties of colloidal sols are discussed, including how they are lyophilic or lyophobic, how particles are solvated, how they are prepared, and how they are affected by electrolytes. Various shapes of colloidal particles and classifications based on dispersion medium and phase are also summarized. The document concludes with brief discussions of coacervation and peptization processes.
This document discusses how gel networks can be used in the pharmaceutical industry to influence crystal growth of active pharmaceutical ingredients (APIs). It begins by providing background on how gels have been used for over 100 years to grow high quality crystals. Recent research interest has focused on using low molecular weight gelators (LMWGs) which can self-assemble to form reversible gel networks. These gels can slow crystal growth and produce crystals with novel habits, polymorphs, and chirality. The document discusses how gels have been used to modify the habit of asparagine monohydrate crystals and screens for new polymorphs. It suggests LMWG gels that undergo triggered gelation could be useful for growing pharmaceutical crystals
This document summarizes the history and discovery of hydrogels. It discusses how Otto and Lim first proposed the use of PHEMA hydrogels in contact lenses in 1960. Lim synthesized some of the first hydrogel materials somewhat by accident in 1954. Since then, hydrogels have found applications in drug delivery, tissue engineering, contact lenses, and other biomedical uses due to their biocompatibility and ability to absorb large amounts of water. The document also discusses stimuli-responsive and "smart" hydrogels that can release drugs in response to environmental triggers like pH, temperature, and electric fields.
Hydrogels introduction and applications in biology and enAndrew Simoi
Hydrogels are water-swollen, crosslinked polymers that can absorb large amounts of water. They have a variety of applications including in soft contact lenses, drug delivery, wound healing, and tissue engineering. Hydrogels are advantageous for tissue engineering and cell culture as they can mimic extracellular matrix, provide structural support, and allow for nutrient transport. They are also useful for drug delivery as they allow controlled release of molecules. The document discusses the properties, types, advantages and uses of hydrogels.
In situ gelling system for drug deliveryAhmad Shaddad
This document discusses in situ gel drug delivery systems. It defines in situ gels as drug delivery systems that are in solution form before administration but gelate inside the body. The gelation is triggered by factors like temperature, pH, ions, or UV exposure. This allows sustained drug release. In situ gels provide benefits like ease of use, improved bioavailability, and patient compliance. The document then categorizes and describes different types of in situ gel systems and polymers used to make them, providing examples of their use in oral, nasal, ocular, rectal/vaginal, and parental applications.
An overview of nanogel drug delivery system it contains the information about gel & nanogel ,mechanism & routes of nanogel administration etc . Its very useful when studing the novel drug delivery system. It is also useful during formulation of Nanogel.
This document provides an overview of suspensions, including their classification, properties, formulation, and stability. Key points include:
- Suspensions are heterogeneous systems with an insoluble dispersed phase distributed throughout a continuous phase. They can be classified based on their intended use, concentration of solids, particle size, and electrokinetic properties.
- Interfacial properties like surface tension affect particle flocculation and sedimentation. Surfactants can reduce surface tension to promote deflocculation.
- Particle size, concentration, and Brownian motion influence sedimentation rates. Flocculated particles settle faster but are easier to redisperse than deflocculated particles.
- Stable suspensions are formulated using vehicles to
Niosome is a novel drug delivery system used for drug delivery to special area Or we can say it is used for targated drug delivery system.
Niosome are superior carrier than liposome as they are made up of non ionic surfectants. Niosome are more stable and more effective carrier than liposome and specialy ideal for hydrophobic and peptide drug
Colloids have particle sizes between 1 nm and 1000 nm. They are classified as lyophilic, lyophobic, or association colloids based on particle interactions with the dispersion medium. Lyophilic colloids readily disperse in the medium while lyophobic colloids do not. Association colloids form micelles above a critical micelle concentration. Colloids demonstrate optical properties like Tyndall effect and can be imaged with electron microscopes. They also exhibit kinetic properties including Brownian motion, diffusion, osmotic pressure, and sedimentation. Colloidal particles are often electrically charged, leading to electrokinetic phenomena like electrophoresis and electroosmosis. Stability is important for preventing
This document discusses the use of radiation for the preparation of hydrogels. It begins by defining hydrogels as polymer networks that are hydrophilic and absorbent, similar to natural tissue. Two common types of radiation used are gamma rays and electron beams. Common polymers used in preparation include PVAL, PVP, PEO, and PAA. The principle of preparation involves irradiating an aqueous polymer solution, which causes cross-linking between polymer chains and formation of a gel. The method involves alternately irradiating the polymer solution with gamma rays and electron beams to create radicals and new covalent bonds, cross-linking the polymers into a semi-solid hydrogel. Applications of hydrogels include use in bi
The document discusses coarse dispersions and suspensions. It defines a suspension as an insoluble solid dispersed in a liquid medium where the particles are larger than 0.1 μm. Common types of suspensions include orally administered, ophthalmic, and injectable suspensions. Desirable qualities include minimal settling, uniform distribution, and appropriate viscosity. The document outlines factors that influence particle interactions like surface energy and interfacial tension. It also discusses strategies to achieve stability including controlled flocculation, use of surfactants, polymers, and structured vehicles.
The document discusses suspensions, which are heterogeneous systems with small, solid particles dispersed throughout a liquid medium. Suspensions can be used orally, parenterally, or externally. They are divided into coarse and colloidal suspensions based on particle size. Various factors including particle size and distribution, viscosity, and stability must be considered for suspension formulation and production. Common methods for preparing suspensions involve using mortar and pestle or mixing equipment depending on the materials used.
hydro gels compositions and applicationsAli Al-Rufaye
Hydrogels are three-dimensional polymer networks that can absorb large amounts of water but do not dissolve. They have properties similar to natural tissue and are biocompatible. Hydrogels can be classified based on their degree of swelling, porosity, biodegradability, and type of crosslinking. They are used in a variety of biomedical applications including drug delivery, contact lenses, and tissue engineering due to their water retention and flexibility. Hydrogels can be designed to respond to environmental stimuli like temperature or pH changes to control drug release. Current research is developing self-healing hydrogels for uses like medical sutures and targeted drug delivery.
This document defines and describes gels and magmas. It discusses:
- The definition of gels as semisolid systems made up of dispersed particles or molecules in a liquid.
- That gels and magmas are considered colloidal dispersions containing particles of colloidal dimension.
- Examples of gelling agents used to form gels including various polymers, gums, and minerals.
- Methods of preparing inorganic gels through precipitation or hydration reactions to form fine particles that interact strongly with water.
- Factors that influence gel formation such as temperature, interactions between particles, and addition of salts or alcohols.
This document provides an overview of pharmaceutical gels. It defines gels as semisolid colloidal systems where a liquid vehicle interacts with colloidal particles. The vehicle can be aqueous, hydroalcoholic, alcoholic, or non-aqueous. Gels are classified based on their continuous phase (organogels, hydrogels, xerogels) or the nature of bonds in their 3D network (dispersed solids, hydrophilic polymers). Common gelling agents include natural polymers, semisynthetic polymers, and synthetic polymers. The document discusses gel properties, preparation methods, manufacturing parameters, examples of topical gels, and applications of gels in drug delivery.
Suspension Formulation Overview For Formulators and Development ScientistsJim McElroy
This document discusses suspension formulations. Suspensions have a dispersed solid phase and a dispersion medium that can be solid, liquid, or gas. Particle interactions can be controlled through electrostatic or steric repulsive forces using formulation techniques. Forces like van der Waals attractions cannot be controlled. Structured vehicles use shear thinning polymers and clays to create suspensions that are semi-solid at rest but fluid with shaking, preventing settling. Flocculation uses electrolytes or polymers to reduce repulsive forces and promote particle aggregation and settling.
3rd Lecture on Adsorption and Colloids | Chemistry Part II | 11th StdAnsari Usama
This document provides information on catalysts and colloids. It defines a catalyst as a substance that increases the rate of a reaction without undergoing a permanent chemical change. It discusses important features of solid catalysts such as catalytic activity and selectivity. It then defines colloids as heterogeneous mixtures with particle sizes between 2-500nm and provides examples. It classifies colloids based on physical state, interaction between phases, and molecular size.
The document discusses the applications of colloids in everyday life. It explains that colloids are mixtures where one substance is dispersed evenly throughout another substance on a nano scale. Some key applications of colloids mentioned include using them in many foods like milk and bread, medicines that are more easily absorbed by the body, water purification by coagulation of impurities, sewage disposal by electrophoresis, and smoke precipitation using charged plates in a Cottrell precipitator. Colloids also play a role in processes like rubber production from latex, leather tanning, soap cleansing action, forming deltas where rivers meet oceans, and giving the sky its blue color.
The document discusses colloids, defining them as heterogeneous mixtures with dispersed particles between 1-100 nm. It classifies different types of colloids based on the state of the dispersed and continuous phases, such as emulsions, foams, sols, and gels. The document also examines the unique properties of colloids, including the Tyndall effect, Brownian motion, and their ability to adsorb other substances.
Colloids play an important role in the pharmaceutical industry. Colloids are mixtures where very small particles of one substance are evenly distributed throughout another. They can be classified based on the state of aggregation or interaction of the dispersed and continuous phases. Common colloidal systems used in medicine include eye lotions, sulphur for skin conditions, various metals as therapeutic agents, and plasma proteins. Colloids increase the solubility, stability, and bioavailability of drugs.
Nature of stability of Colloidal SystemsAyeesha Tarik
This document provides an overview of colloidal systems and their classification. It begins by defining colloids as mixtures where one substance is dispersed as minute particles throughout another substance. Colloids are classified based on the state of the dispersed and dispersion mediums, which can be solid, liquid or gas. This results in different types of colloids including sols, emulsions, gels and aerosols. The document also discusses factors that influence the stability of colloids such as electrical forces, interaction with the dispersion medium, and stabilization methods.
Hydrogels are cross-linked polymer networks that can absorb large amounts of water. They come in natural and synthetic varieties. Hydrogels can be classified based on their synthesis method (homopolymer, copolymer, multipolymer), structure (amorphous, semi-crystalline, hydrogen-bonded), or electric charge (non-ionic, ionic, amphoteric, zwitterionic). Hydrogels have properties like high absorption capacity and biodegradability. They have a wide range of applications including use in contact lenses, hygiene products, wound dressings, and drug delivery.
This document summarizes a seminar on colloidal dispersions presented by Sayani Saha. It defines colloidal dispersions as systems with a dispersed particle phase and continuous dispersion medium between 1-1000 nm. Dispersions are classified by size as molecular, colloidal, or coarse dispersions. The properties of colloidal sols are discussed, including how they are lyophilic or lyophobic, how particles are solvated, how they are prepared, and how they are affected by electrolytes. Various shapes of colloidal particles and classifications based on dispersion medium and phase are also summarized. The document concludes with brief discussions of coacervation and peptization processes.
This document discusses how gel networks can be used in the pharmaceutical industry to influence crystal growth of active pharmaceutical ingredients (APIs). It begins by providing background on how gels have been used for over 100 years to grow high quality crystals. Recent research interest has focused on using low molecular weight gelators (LMWGs) which can self-assemble to form reversible gel networks. These gels can slow crystal growth and produce crystals with novel habits, polymorphs, and chirality. The document discusses how gels have been used to modify the habit of asparagine monohydrate crystals and screens for new polymorphs. It suggests LMWG gels that undergo triggered gelation could be useful for growing pharmaceutical crystals
This document summarizes the history and discovery of hydrogels. It discusses how Otto and Lim first proposed the use of PHEMA hydrogels in contact lenses in 1960. Lim synthesized some of the first hydrogel materials somewhat by accident in 1954. Since then, hydrogels have found applications in drug delivery, tissue engineering, contact lenses, and other biomedical uses due to their biocompatibility and ability to absorb large amounts of water. The document also discusses stimuli-responsive and "smart" hydrogels that can release drugs in response to environmental triggers like pH, temperature, and electric fields.
Hydrogels introduction and applications in biology and enAndrew Simoi
Hydrogels are water-swollen, crosslinked polymers that can absorb large amounts of water. They have a variety of applications including in soft contact lenses, drug delivery, wound healing, and tissue engineering. Hydrogels are advantageous for tissue engineering and cell culture as they can mimic extracellular matrix, provide structural support, and allow for nutrient transport. They are also useful for drug delivery as they allow controlled release of molecules. The document discusses the properties, types, advantages and uses of hydrogels.
In situ gelling system for drug deliveryAhmad Shaddad
This document discusses in situ gel drug delivery systems. It defines in situ gels as drug delivery systems that are in solution form before administration but gelate inside the body. The gelation is triggered by factors like temperature, pH, ions, or UV exposure. This allows sustained drug release. In situ gels provide benefits like ease of use, improved bioavailability, and patient compliance. The document then categorizes and describes different types of in situ gel systems and polymers used to make them, providing examples of their use in oral, nasal, ocular, rectal/vaginal, and parental applications.
An overview of nanogel drug delivery system it contains the information about gel & nanogel ,mechanism & routes of nanogel administration etc . Its very useful when studing the novel drug delivery system. It is also useful during formulation of Nanogel.
This document provides an overview of suspensions, including their classification, properties, formulation, and stability. Key points include:
- Suspensions are heterogeneous systems with an insoluble dispersed phase distributed throughout a continuous phase. They can be classified based on their intended use, concentration of solids, particle size, and electrokinetic properties.
- Interfacial properties like surface tension affect particle flocculation and sedimentation. Surfactants can reduce surface tension to promote deflocculation.
- Particle size, concentration, and Brownian motion influence sedimentation rates. Flocculated particles settle faster but are easier to redisperse than deflocculated particles.
- Stable suspensions are formulated using vehicles to
Niosome is a novel drug delivery system used for drug delivery to special area Or we can say it is used for targated drug delivery system.
Niosome are superior carrier than liposome as they are made up of non ionic surfectants. Niosome are more stable and more effective carrier than liposome and specialy ideal for hydrophobic and peptide drug
Colloids have particle sizes between 1 nm and 1000 nm. They are classified as lyophilic, lyophobic, or association colloids based on particle interactions with the dispersion medium. Lyophilic colloids readily disperse in the medium while lyophobic colloids do not. Association colloids form micelles above a critical micelle concentration. Colloids demonstrate optical properties like Tyndall effect and can be imaged with electron microscopes. They also exhibit kinetic properties including Brownian motion, diffusion, osmotic pressure, and sedimentation. Colloidal particles are often electrically charged, leading to electrokinetic phenomena like electrophoresis and electroosmosis. Stability is important for preventing
This document discusses the use of radiation for the preparation of hydrogels. It begins by defining hydrogels as polymer networks that are hydrophilic and absorbent, similar to natural tissue. Two common types of radiation used are gamma rays and electron beams. Common polymers used in preparation include PVAL, PVP, PEO, and PAA. The principle of preparation involves irradiating an aqueous polymer solution, which causes cross-linking between polymer chains and formation of a gel. The method involves alternately irradiating the polymer solution with gamma rays and electron beams to create radicals and new covalent bonds, cross-linking the polymers into a semi-solid hydrogel. Applications of hydrogels include use in bi
The document discusses coarse dispersions and suspensions. It defines a suspension as an insoluble solid dispersed in a liquid medium where the particles are larger than 0.1 μm. Common types of suspensions include orally administered, ophthalmic, and injectable suspensions. Desirable qualities include minimal settling, uniform distribution, and appropriate viscosity. The document outlines factors that influence particle interactions like surface energy and interfacial tension. It also discusses strategies to achieve stability including controlled flocculation, use of surfactants, polymers, and structured vehicles.
The document discusses suspensions, which are heterogeneous systems with small, solid particles dispersed throughout a liquid medium. Suspensions can be used orally, parenterally, or externally. They are divided into coarse and colloidal suspensions based on particle size. Various factors including particle size and distribution, viscosity, and stability must be considered for suspension formulation and production. Common methods for preparing suspensions involve using mortar and pestle or mixing equipment depending on the materials used.
hydro gels compositions and applicationsAli Al-Rufaye
Hydrogels are three-dimensional polymer networks that can absorb large amounts of water but do not dissolve. They have properties similar to natural tissue and are biocompatible. Hydrogels can be classified based on their degree of swelling, porosity, biodegradability, and type of crosslinking. They are used in a variety of biomedical applications including drug delivery, contact lenses, and tissue engineering due to their water retention and flexibility. Hydrogels can be designed to respond to environmental stimuli like temperature or pH changes to control drug release. Current research is developing self-healing hydrogels for uses like medical sutures and targeted drug delivery.
This document defines and describes gels and magmas. It discusses:
- The definition of gels as semisolid systems made up of dispersed particles or molecules in a liquid.
- That gels and magmas are considered colloidal dispersions containing particles of colloidal dimension.
- Examples of gelling agents used to form gels including various polymers, gums, and minerals.
- Methods of preparing inorganic gels through precipitation or hydration reactions to form fine particles that interact strongly with water.
- Factors that influence gel formation such as temperature, interactions between particles, and addition of salts or alcohols.
This document provides an overview of pharmaceutical gels. It defines gels as semisolid colloidal systems where a liquid vehicle interacts with colloidal particles. The vehicle can be aqueous, hydroalcoholic, alcoholic, or non-aqueous. Gels are classified based on their continuous phase (organogels, hydrogels, xerogels) or the nature of bonds in their 3D network (dispersed solids, hydrophilic polymers). Common gelling agents include natural polymers, semisynthetic polymers, and synthetic polymers. The document discusses gel properties, preparation methods, manufacturing parameters, examples of topical gels, and applications of gels in drug delivery.
This document provides information about colloids. It defines a colloid as a substance microscopically dispersed throughout another substance. Colloidal solutions contain insoluble particles ranging from 1-1000 nm in size suspended in another substance. Colloids can be classified based on physical state, interaction type, particle size, appearance, or electrical charge. Common examples of colloids include milk, blood, fog and smoke. Colloids can be separated via mechanical dispersion, electrical methods, peptization, or condensation. Properties of colloids depend on whether they are gels, foams, emulsions or aerosols.
This document summarizes key biological molecules:
- Starch and glycogen are energy storage compounds in plants and animals, respectively, made of glucose molecules in branching structures; cellulose is made of glucose molecules bonded together in plant cell walls.
- Lipids include triglycerides that store energy as fat and oils, and phospholipids that form cell membranes. The emulsion test detects lipids.
- Proteins are polymers of amino acids that fold into precise shapes determining function; they form alpha-helices and beta-pleated sheets through hydrogen bonding.
- Carbohydrates range from monosaccharides like glucose to polysaccharides like starch; Benedict's reagent detects sugars.
- Water enables life through its solvent
Colloids are essential to life and are found in cells, blood, and body fluids. Colloidal science enhances understanding of colloids and their applications to human health. Colloids can be manufactured using grinding, wave action, liquid dispersion, chemical processes, or electrically, with electrical methods producing the best results. Properly prepared colloids do not require stabilizers and can remain suspended indefinitely, making them useful for health applications like nutrient delivery and tissue regeneration.
Suspension is a two-phase system with a solid dispersed in a liquid. Suspensions offer advantages like masking unpleasant tastes, providing prolonged drug release, and increased bioavailability. Factors like particle size, viscosity, and density difference between solid and liquid affect sedimentation rate per Stokes' law. Formulating stable suspensions requires choosing vehicles that maintain particles in deflocculated state or produce redispersible floccules. Wetting powder particles thoroughly before adding to the vehicle aids in proper dispersion.
Colloids are heterogeneous mixtures where one substance is microscopically dispersed throughout another. They can be classified as lyophilic or lyophobic depending on the affinity between the dispersed and dispersion phases. Common colloidal phenomena include the Tyndall effect where light scatters off colloidal particles, Brownian motion involving random particle movement, and electrophoresis using an electric field to separate charged particles. Colloids have many applications from food to medicine to water purification.
The document discusses different types of colloidal systems including emulsions, sols, gels, and foams. It provides examples of each type in foods such as salad dressing as an emulsion, gravy as a sol, baked custard as a gel, and egg white foam as a foam. It also describes key properties of colloids like small particle size visible only under microscope and Brownian motion. Common colloidal systems in foods, properties of each type, and methods of formation and stabilization are summarized.
Gel is an intermediate state of matter between solid and liquid. Hydrogels are polymeric networks that can absorb large amounts of water. Poly-hydroxyethyl methacrylate (PHEMA) hydrogels are biocompatible and have water content similar to living tissues. PHEMA hydrogels are used in applications such as contact lenses, drug delivery systems, and tissue engineering scaffolds due to their permeability and elastic properties.
Colloidal dispersions are heterogeneous systems where one substance is divided into small particles, between 1 nm and 1 μm, dispersed throughout a second substance. They can be classified based on the dispersed and dispersion medium, such as sols where the medium is a liquid. Colloidal particles exhibit properties like Brownian motion, diffusion, and Tyndall effect. Their size, shape, and surface charge affect characteristics like stability, flowability, and pharmacological effects. Purification methods remove electrolytes and impurities through dialysis, ultrafiltration, or electrodialysis.
Nanogels are innovative drug delivery system that can play an integral part in pointing out many issues related to old and modern courses of treatment such as nonspecific effects and poor stability.
This document discusses colloids, including their definition and classification. Colloids can be classified into different types of mixtures including sols, foams, emulsions, and gels. Sols are solid particles dispersed in a liquid, foams contain gas pockets in a liquid or solid, emulsions involve two immiscible liquids, and gels contain molecules of a liquid dispersed within a solid matrix. The document also provides examples of each type of colloidal mixture and discusses reversible versus irreversible colloid formation.
This document discusses colloids, including their definition and classification. Colloids can be classified into different types of mixtures including sols, foams, emulsions, and gels. Sols are solid particles dispersed in a liquid, foams contain gas pockets in a liquid or solid, emulsions involve two immiscible liquids, and gels contain molecules of a liquid dispersed within a solid matrix. The document also provides examples of each type of colloidal mixture and discusses reversible versus irreversible colloid formation.
Gels are semisolid systems used for various routes of drug administration like oral, topical, vaginal, and rectal. They consist of a gelling agent dissolved or dispersed in a liquid vehicle to form a colloidal suspension. Common gelling agents include acacia, pectin, starch, and xanthan gum. Gels are classified based on their continuous phase as hydrogels containing water or organogels containing organic liquids. They can also be classified based on the bonds forming the 3D network into physically crosslinked systems or chemically crosslinked polymer networks. Preparation methods for gels include fusion, cold, and dispersion techniques. Gels find applications as lubricants, patches, electro
The document provides an overview of surface chemistry concepts including adsorption, types of adsorption (physisorption and chemisorption), factors affecting adsorption, adsorption isotherms, catalysis, colloids, and classification of colloids. It defines key terms and describes processes such as adsorption, mechanisms of adsorption, differences between physisorption and chemisorption, applications of adsorption, types and mechanisms of catalysis, preparation and purification of colloids, and properties of colloidal solutions. The document aims to explain important surface chemistry concepts and phenomena.
This document discusses semisolid dosage forms, including their definition, ideal properties, types, mechanisms of drug penetration, and factors influencing penetration. It defines semisolid dosage forms as dermatological products of semisolid consistency applied to the skin. The main types discussed are ointments, creams, pastes, and gels. It also covers the rheological and hydrophilic properties of various semisolid bases and how these properties influence drug delivery and consistency.
Hydrogels are cross-linked, three dimensional, hydrophilic polymeric networks with the ability to hold large amount of water within its porous structure.
this ppt is about hydrogel.A hydrogel is a three-dimensional(3D) network of hydrophilic polymers that can swell in water and hold a large amount of water while maintaining the structure due to chemical or physical cross-linking of individual polymer chains. applications Flexibility of hydrogels, which is because of their water content, makes it possible to use them in different condition ranging from industrial to biological fields
A review on techniques and modelling methodologies used for checking electrom...nooriasukmaningtyas
The proper function of the integrated circuit (IC) in an inhibiting electromagnetic environment has always been a serious concern throughout the decades of revolution in the world of electronics, from disjunct devices to today’s integrated circuit technology, where billions of transistors are combined on a single chip. The automotive industry and smart vehicles in particular, are confronting design issues such as being prone to electromagnetic interference (EMI). Electronic control devices calculate incorrect outputs because of EMI and sensors give misleading values which can prove fatal in case of automotives. In this paper, the authors have non exhaustively tried to review research work concerned with the investigation of EMI in ICs and prediction of this EMI using various modelling methodologies and measurement setups.
Batteries -Introduction – Types of Batteries – discharging and charging of battery - characteristics of battery –battery rating- various tests on battery- – Primary battery: silver button cell- Secondary battery :Ni-Cd battery-modern battery: lithium ion battery-maintenance of batteries-choices of batteries for electric vehicle applications.
Fuel Cells: Introduction- importance and classification of fuel cells - description, principle, components, applications of fuel cells: H2-O2 fuel cell, alkaline fuel cell, molten carbonate fuel cell and direct methanol fuel cells.
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELgerogepatton
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
Comparative analysis between traditional aquaponics and reconstructed aquapon...bijceesjournal
The aquaponic system of planting is a method that does not require soil usage. It is a method that only needs water, fish, lava rocks (a substitute for soil), and plants. Aquaponic systems are sustainable and environmentally friendly. Its use not only helps to plant in small spaces but also helps reduce artificial chemical use and minimizes excess water use, as aquaponics consumes 90% less water than soil-based gardening. The study applied a descriptive and experimental design to assess and compare conventional and reconstructed aquaponic methods for reproducing tomatoes. The researchers created an observation checklist to determine the significant factors of the study. The study aims to determine the significant difference between traditional aquaponics and reconstructed aquaponics systems propagating tomatoes in terms of height, weight, girth, and number of fruits. The reconstructed aquaponics system’s higher growth yield results in a much more nourished crop than the traditional aquaponics system. It is superior in its number of fruits, height, weight, and girth measurement. Moreover, the reconstructed aquaponics system is proven to eliminate all the hindrances present in the traditional aquaponics system, which are overcrowding of fish, algae growth, pest problems, contaminated water, and dead fish.
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
ACEP Magazine edition 4th launched on 05.06.2024Rahul
This document provides information about the third edition of the magazine "Sthapatya" published by the Association of Civil Engineers (Practicing) Aurangabad. It includes messages from current and past presidents of ACEP, memories and photos from past ACEP events, information on life time achievement awards given by ACEP, and a technical article on concrete maintenance, repairs and strengthening. The document highlights activities of ACEP and provides a technical educational article for members.
1. Suspension (chemistry)
From Wikipedia, the free encyclopedia
In chemistry, a suspension is a heterogeneous mixture containing solid particles that are sufficiently
large for sedimentation. Usually they must be larger than 1 micrometer.[1]
The internal phase (solid)
is dispersed throughout the external phase (fluid) through mechanical agitation, with the use of
certain excipients or suspending agents. Unlike colloids, suspensions will eventually settle. An
example of a suspension would be sand in water. The suspended particles are visible under a
microscope and will settle over time if left undisturbed. This distinguishes a suspension from
a colloid, in which the suspended particles are smaller and do not settle.[2]
Colloids and suspensions
are different fromsolutions, in which the dissolved substance (solute) does not exist as a solid, and
solvent and solute are homogeneously mixed.
A suspension of liquid droplets or fine solid particles in a gas is called an aerosol or particulate. In
the atmosphere these consist of fine dust and soot particles, sea
salt, biogenicand volcanogenic sulfates, nitrates, and cloud droplets.
Suspensions are classified on the basis of the dispersed phase and the dispersion medium, where
the former is essentially solid while the latter may either be a solid, a liquid, or a gas.
In modern chemical process industries, high shear mixing technology has been used to create many
novel suspensions.
Suspensions are unstable from the thermodynamic point of view; however, they can be kinetically
stable over a large period of time, which determines their shelf life. This time span needs to be
measured to ensure the best product quality to the final consumer. “Dispersion stability refers to the
ability of a dispersion to resist change in its properties over time.” D.J. McClements.[3]
In chemistry, a suspension is a mixture of two or more substances. In a suspension, very small pieces of solid are spread
through a liquidbut do not dissolve. [1]
If left still, the solid pieces will separate from the liquid and either fall to the bottom or
rise to the top. Sand in water is a suspension. Suspensions may separate quickly or stay suspended for a long time,
depending on what they contain.
If a liquid is suspended in another liquid, it is called an emulsion. Milk is an emulsion. If a liquid is suspended in a gas it is
an aerosol. Mistis an aerosol.
2. Gel
From Wikipedia, the free encyclopedia
For other uses, see Gel (disambiguation).
An upturned vial of hair gel
A gel (coined by 19th-century Scottish chemist Thomas Graham, by clipping from gelatine[1]
) is a solid, jelly-like material that
can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-
linked system, which exhibits no flow when in the steady-state.[2]
A cross-link is a bond that links one polymer chain to
another.By weight, gels are mostly liquid, yet they behave like solids due to a three-dimensional cross-linked network within
the liquid. It is the crosslinking within the fluid that give a gel its structure (hardness) and contribute to the adhesive stick
(tack).[3]
In this way gels are a dispersion of molecules of a liquid within a solid in which the solid is the continuous phase
and the liquid is the discontinuous phase.
IUPAC definition
Gel: Nonfluid colloidal network or polymer network that is expanded throughout its whole
volume by a fluid.[4]
Note 1: A gel has a finite, usually rather small, yield stress.
Note 2: A gel can contain:
(i) a covalent polymer network, e.g., a network formed by crosslinking polymer chains
or by nonlinear polymerization;
(ii) a polymer network formed through the physical aggregation of polymer chains,
caused by hydrogen bonds, crystallization, helix formation, complexation, etc., that
3. results in regions of local order acting as the network junction points. The resulting
swollen network may be termed a “thermoreversible gel” if the regions of local order
are thermally reversible;
(iii) a polymer network formed through glassy junction points, e.g., one based on
block copolymers. If the junction points are thermally reversible glassy domains, the
resulting swollen network may also be termed a thermoreversible gel;
(iv) lamellar structures including mesophases {Ref.[5]
defines lamellar crystal and
mesophase}, e.g., soap gels, phospholipids, and clays;
(v) particulate disordered structures, e.g., a flocculent precipitate usually consisting
of particles with large geometrical anisotropy, such as in V2O5 gels and globular
or fibrillar protein gels.
Note 3: Corrected from ref.,[6]
where the definition is via the property identified in Note 1
(above) rather than of the structural characteristics that describe a gel.[7]
Hydrogel: Gel in which the swelling agent is water.
Note 1: The network component of a hydrogel is usually a polymer network.
Note 2: A hydrogel in which the network component is a colloidal network may be referred
to as an aquagel.
Note 3: Definition quoted from refs.[7][8][9]
Contents
[hide]
1 Composition
o 1.1 Cationic polymers
2 Types
o 2.1 Hydrogels
o 2.2 Organogels
o 2.3 Xerogels
3 Properties
4 Animal produced
5 Applications
6 See also
7 References
8 External links
Composition[edit]
Gels consist of a solid three-dimensional network that spans the volume of a liquid medium and
ensnares it through surface tension effects. This internal network structure may result from
4. physical bonds (physical gels) or chemical bonds (chemical gels), as well as crystallites or other
junctions that remain intact within the extending fluid. Virtually any fluid can be used as an
extender including water (hydrogels), oil, and air (aerogel). Both by weight and volume, gels are
mostly fluid in composition and thus exhibit densities similar to those of their constituent liquids.
Edible jelly is a common example of a hydrogel and has approximately the density of water.
Cationic polymers[edit]
Cationic polymers are positively charged polymers. Their positive charges prevent the formation of
coiled polymers. This allows them to contribute more to viscosity in their stretched state, because
the stretched-out polymer takes up more space. Gel is a colloid solution of dispersion phase as
liquid and dispersion medium as solid.
Types[edit]
Hydrogels[edit]
See also: Superabsorbent polymer and Self-healing hydrogels
Hydrogel is a network of polymer chains that are hydrophilic, sometimes found as a colloidal gel in
which water is the dispersion medium. Hydrogels are highly absorbent (they can contain over
99.9% water[citation needed]
) natural or synthetic polymers. Hydrogels also possess a degree of
flexibility very similar to natural tissue, due to their significant water content. Common uses for
hydrogels include:
currently used as scaffolds in tissue engineering. When used as scaffolds, hydrogels may
contain human cells to repair tissue.
hydrogel-coated wells have been used for cell culture[10]
environmentally sensitive hydrogels which are also known as 'Smart Gels' or 'Intelligent Gels'.
These hydrogels have the ability to sense changes of pH, temperature, or the concentration
of metabolite and release their load as result of such a change.
as sustained-release drug delivery systems.
provide absorption, desloughing and debriding of necrotic and fibrotic tissue.
hydrogels that are responsive to specific molecules, such as glucose or antigens, can be
used as biosensors, as well as in DDS[clarification needed]
.
used in disposable diapers where they absorb urine, or in sanitary napkins
contact lenses (silicone hydrogels, polyacrylamides, polymacon)
EEG and ECG medical electrodes using hydrogels composed of cross-linked polymers
(polyethylene oxide, polyAMPS and polyvinylpyrrolidone)
water gel explosives
rectal drug delivery and diagnosis
encapsulation of quantum dots
5. Other, less common uses include
breast implants
now used in glue.
granules for holding soil moisture in arid areas
dressings for healing of burn or other hard-to-heal wounds. Wound gels are excellent for
helping to create or maintain a moist environment.
reservoirs in topical drug delivery; particularly ionic drugs, delivered by iontophoresis (see ion
exchange resin)
Common ingredients are e.g. polyvinyl alcohol, sodium polyacrylate, acrylate polymers
and copolymers with an abundance of hydrophilic groups.
Natural hydrogel materials are being investigated for tissue engineering; these materials include
agarose, methylcellulose, hyaluronan, and other naturally derived polymers.
Organogels[edit]
See also: Organogels
An organogel is a non-crystalline, non-glassy thermoreversible (thermoplastic) solid material
composed of a liquid organic phase entrapped in a three-dimensionally cross-linked network. The
liquid can be, for example, an organic solvent, mineral oil, or vegetable oil.
The solubility and particle dimensions of the structurant are important characteristics for
the elastic properties and firmness of the organogel. Often, these systems are based on self-
assembly of the structurant molecules.[11][12]
Organogels have potential for use in a number of applications, such as
in pharmaceuticals,[13]
cosmetics, art conservation,[14]
and food.[15]
An example of formation of an
undesired thermoreversible network is the occurrence of wax crystallization in petroleum.[16]
Xerogels[edit]
A xerogel /ˈzɪ ərɵ dʒ ɛ l/ is a solid formed from a gel by drying with unhindered shrinkage.
Xerogels usually retain high porosity (15–50%) and enormous surface area (150–900 m2
/g), along
with very small pore size (1–10 nm). When solvent removal occurs under supercritical conditions,
the network does not shrink and a highly porous, low-density material known as an aerogel is
produced. Heat treatment of a xerogel at elevated temperature produces
viscous sintering (shrinkage of the xerogel due to a small amount of viscous flow) and effectively
transforms the porous gel into a dense glass.
Properties[edit]
Many gels display thixotropy – they become fluid when agitated, but resolidify when resting. In
general, gels are apparently solid, jelly-like materials. By replacing the liquid with gas it is possible
to prepare aerogels, materials with exceptional properties including very low density, high specific
surface areas, and excellent thermal insulation properties.
6. Animal produced[edit]
Some species secrete gels that are effective in parasite control. For example, the long-finned pilot
whale secretes an enzymatic gel that rests on the outer surface of this animal and helps prevent
other organisms from establishing colonies on the surface of these whales' bodies.[17]
Hydrogels existing naturally in the body include mucus, the vitreous humor of the eye, cartilage,
tendons and blood clots. Their viscoelastic nature results in the soft tissue component of the body,
disparate from the mineral-based hard tissue of the skeletal system. Researchers are actively
developing synthetically derived tissue replacement technologies derived from hydrogels, for both
temporary implants (degradable) and permanent implants (non-degradable). A review article on
the subject discusses the use of hydrogels for nucleus pulposus replacement, cartilage
replacement, and synthetic tissue models.[18]
Applications[edit]
Many substances can form gels when a suitable thickener or gelling agent is added to their
formula. This approach is common in manufacture of wide range of products, from foods to paints
and adhesives.
In fiber optics communications, a soft gel resembling "hair gel" in viscosity is used to fill the plastic
tubes containing the fibers. The main purpose of the gel is to prevent water intrusion if the buffer
tube is breached, but the gel also buffers the fibers against mechanical damage when the tube is
bent around corners during installation, or flexed. Additionally, the gel acts as a processing aid
when the cable is being constructed, keeping the fibers central whilst the tube material is extruded
around it.
See also[edit]