Emulsions are thermodynamically unstable systems consisting of two immiscible liquids, one dispersed as globules in the other. Emulsifying agents are needed to stabilize the droplets and prevent separation. Emulsions can be oil-in-water or water-in-oil depending on the emulsifying agent used. Pharmaceutical applications of emulsions include masking bitter tastes, sustained drug release, and use in intravenous products. Emulsion stability can be affected by factors like globule size, density differences, and viscosity. Quality control tests assess properties such as particle size, viscosity, and phase separation over time.
Emulsions are thermodynamically unstable systems with one liquid dispersed as fine droplets in another liquid stabilized by an emulsifying agent. There are two main types - oil-in-water (O/W) and water-in-oil (W/O) emulsions. Emulsions can be used to deliver drugs, mask tastes, administer oils, and reduce irritancy. They are challenging to formulate and stabilize due to inherent instability. Emulsifying agents like surfactants form protective interfacial films to prevent separation. Common pharmaceutical applications include masking tastes, sustained release, parenteral nutrition, and topical products. Stability issues include flocculation, creaming, coalescence,
The document discusses emulsions, which are mixtures of two or more liquids that do not normally mix. It defines the key types of emulsions as oil-in-water (O/W), water-in-oil (W/O), and multiple emulsions. It also explains the differences between O/W and W/O emulsions and describes detection tests that can identify the emulsion type. Finally, it provides examples of common emulsifying agents like lecithin, soap, and gum and discusses their properties and uses in emulsions.
This document discusses mixing and homogenization processes. It defines mixing as combining two or more substances together, and identifies perfect mixing as each particle of one material lying adjacent to a particle of the other material. The objectives of mixing are outlined. There are three types of mixtures discussed: positive, negative, and neutral. The mechanisms and equipment used for mixing powders, liquids, and semi-solids are described. Homogenization is defined as preparing a fine emulsion from a coarse one by converting large globules to small globules. Common homogenization equipment like hand homogenizers, Silverson mixers, and colloidal mills are summarized.
Pharmacy#Flow properties of powders#Physical pharmaceuticsRajkumar Kumawat
Flow properties of powders can be classified as free flowing or cohesive and are influenced by particle size, shape, density, moisture content, and electrostatic charge. Flow properties impact tabletting and encapsulation processes. Factors like nature, size distribution, shape, moisture, and surface morphology of particles affect powder flow. Larger, more spherical particles with narrow size distribution and low moisture content exhibit better flow than smaller, irregular particles. Common tests to evaluate flow include angle of repose, compressibility index, and cohesion. Flow can be improved by increasing particle size, producing spherical particles, or adding glidants or lubricants.
Liniments are topical preparations intended for external application to relieve conditions like itching, dry skin, pain, and inflammation, and can be alcoholic, oily, or emulsion bases. They are applied with friction and contain ingredients like analgesics, rubefacients, and counterirritants. Common examples of liniments include Compound Calamine Liniment, Efficascent Oil, and White Liniment.
Pharmaceutical Emulsions are thermodynamically unstable mixtures of two immiscible liquids stabilized by an emulsifying agent. They can be oil-in-water (O/W) or water-in-oil (W/O) emulsions depending on the dispersed and continuous phases. Emulsifying agents like surfactants, hydrocolloids, and solid particles form protective films around droplets and increase viscosity to prevent coalescence. Stability issues include creaming, cracking, and phase inversion. Methods to enhance stability are reducing droplet size, increasing viscosity, using emulsifying agents, and controlling storage temperature.
This document discusses size separation techniques used to separate particles of different sizes. Size separation, also known as sieving or screening, is important to obtain particles of a narrow size range or uniform particle size. It improves properties like mixing, flow, and suspension stability. Common mechanisms of size separation include agitation (oscillation, vibration, gyration), brushing, and centrifugal forces. Standard sieves made of woven wire or mesh are used to separate particles according to their ability to pass through openings of different sizes. Instruments like sieve shakers, cyclones, air separators, and filter bags can be employed for size separation in pharmaceutical applications.
Emulsions are thermodynamically unstable systems with one liquid dispersed as fine droplets in another liquid stabilized by an emulsifying agent. There are two main types - oil-in-water (O/W) and water-in-oil (W/O) emulsions. Emulsions can be used to deliver drugs, mask tastes, administer oils, and reduce irritancy. They are challenging to formulate and stabilize due to inherent instability. Emulsifying agents like surfactants form protective interfacial films to prevent separation. Common pharmaceutical applications include masking tastes, sustained release, parenteral nutrition, and topical products. Stability issues include flocculation, creaming, coalescence,
The document discusses emulsions, which are mixtures of two or more liquids that do not normally mix. It defines the key types of emulsions as oil-in-water (O/W), water-in-oil (W/O), and multiple emulsions. It also explains the differences between O/W and W/O emulsions and describes detection tests that can identify the emulsion type. Finally, it provides examples of common emulsifying agents like lecithin, soap, and gum and discusses their properties and uses in emulsions.
This document discusses mixing and homogenization processes. It defines mixing as combining two or more substances together, and identifies perfect mixing as each particle of one material lying adjacent to a particle of the other material. The objectives of mixing are outlined. There are three types of mixtures discussed: positive, negative, and neutral. The mechanisms and equipment used for mixing powders, liquids, and semi-solids are described. Homogenization is defined as preparing a fine emulsion from a coarse one by converting large globules to small globules. Common homogenization equipment like hand homogenizers, Silverson mixers, and colloidal mills are summarized.
Pharmacy#Flow properties of powders#Physical pharmaceuticsRajkumar Kumawat
Flow properties of powders can be classified as free flowing or cohesive and are influenced by particle size, shape, density, moisture content, and electrostatic charge. Flow properties impact tabletting and encapsulation processes. Factors like nature, size distribution, shape, moisture, and surface morphology of particles affect powder flow. Larger, more spherical particles with narrow size distribution and low moisture content exhibit better flow than smaller, irregular particles. Common tests to evaluate flow include angle of repose, compressibility index, and cohesion. Flow can be improved by increasing particle size, producing spherical particles, or adding glidants or lubricants.
Liniments are topical preparations intended for external application to relieve conditions like itching, dry skin, pain, and inflammation, and can be alcoholic, oily, or emulsion bases. They are applied with friction and contain ingredients like analgesics, rubefacients, and counterirritants. Common examples of liniments include Compound Calamine Liniment, Efficascent Oil, and White Liniment.
Pharmaceutical Emulsions are thermodynamically unstable mixtures of two immiscible liquids stabilized by an emulsifying agent. They can be oil-in-water (O/W) or water-in-oil (W/O) emulsions depending on the dispersed and continuous phases. Emulsifying agents like surfactants, hydrocolloids, and solid particles form protective films around droplets and increase viscosity to prevent coalescence. Stability issues include creaming, cracking, and phase inversion. Methods to enhance stability are reducing droplet size, increasing viscosity, using emulsifying agents, and controlling storage temperature.
This document discusses size separation techniques used to separate particles of different sizes. Size separation, also known as sieving or screening, is important to obtain particles of a narrow size range or uniform particle size. It improves properties like mixing, flow, and suspension stability. Common mechanisms of size separation include agitation (oscillation, vibration, gyration), brushing, and centrifugal forces. Standard sieves made of woven wire or mesh are used to separate particles according to their ability to pass through openings of different sizes. Instruments like sieve shakers, cyclones, air separators, and filter bags can be employed for size separation in pharmaceutical applications.
This document discusses ointments, which are semi-solid topical dosage forms used for therapeutic, protective, or cosmetic purposes. Ointments are greasy preparations containing 80% oil and 20% water that are applied to the skin or mucous membranes. They can contain dissolved, emulsified, or suspended drug ingredients. Ointments are classified based on penetration (epidermic, endodermic, diadermic) or therapeutic use (antibiotic, antifungal, anti-inflammatory). Ideal ointment bases are inert, compatible with skin pH, emollient, and release medication readily. Common bases include oleaginous (petrolatum, hard paraffin, liquid paraffin
Test for identification of type of emulsionSantuMistree4
Four tests are used to identify oil-in-water (O/W) and water-in-oil (W/O) emulsions: the dilution test, dye test, conductivity test, and fluorescence test. The dilution test identifies the emulsion type based on whether it dilutes easily with water or oil. The dye test observes emulsion droplets under a microscope after adding an oil-soluble dye. If the continuous phase is colored and droplets are clear, it is a W/O emulsion; if droplets are colored and the continuous phase is clear, it is an O/W emulsion. The conductivity test uses electrodes - if a bulb glows, it is an O/W emulsion, and if not, it is a
This document discusses the evaluation of semi-solid dosage forms. It defines semi-solids and classifies them into different types including ointments, creams, pastes, poultices, gels, and plasters. It describes the key characteristics and uses of each type. The document also covers important ingredients for semi-solids, including bases, and methods for evaluating different properties of semi-solids like penetration rate, absorption, rheology, biological testing, drug content, viscosity, and spreadability.
An emulsion is an unstable mixture of two immiscible liquids stabilized by an emulsifying agent. The document defines emulsions and describes different types including oil-in-water, water-in-oil, multiple, and microemulsions. Methods for preparing emulsions like the continental, English, and bottle methods are outlined. Advantages of emulsions include masking unpleasant tastes, enabling oral or parenteral administration of insoluble compounds, and providing sustained release. However, emulsions are thermodynamically unstable and require proper formulation to avoid issues like creaming or cracking.
This document discusses coarse dispersion suspensions. It defines suspensions as heterogeneous systems with two phases, a solid dispersed phase and a liquid continuous phase. The key points covered include:
- Classifying suspensions based on particle size as coarse, colloidal, or molecular dispersions.
- Theories behind sedimentation behavior, Brownian motion, and electrokinetic properties that impact suspension stability.
- Factors that influence flocculation vs deflocculation like zeta potential, electrolyte concentration, and addition of surfactants or polymers.
- DLVO theory explaining the balance of attractive van der Waals forces and repulsive electrostatic forces between particles.
- How temperature changes can impact physical
This document presents information about emulsions by Anirban Barman for his third year pharmacy course. It discusses the definition of emulsions, factors that affect emulsion stability such as cracking, creaming, and phase inversion. Cracking is the separation into two layers due to globule coalescence. Creaming is the upward movement of dispersed globules, affected by properties like density, viscosity, and temperature based on Stokes' law. Phase inversion is a change from one emulsion type to another, like oil-in-water to water-in-oil. Maintaining emulsion stability is important for ensuring product quality until expiration.
This document discusses emulsions and factors that influence their physical stability. Emulsions are biphasic systems containing both oil and water phases. Emulsifying agents stabilize emulsions by preventing globule coalescence. Stability depends on globule size, viscosity, density differences between phases, and properties of the interface film formed by emulsifying agents. Physical instability can occur via flocculation, creaming, coalescence, and breaking. Phase inversion is also discussed. Methods for evaluating and improving stability include assessing phase separation, globule size, and centrifugation testing. The document outlines preparation of emulsions on small and large scales.
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.
An emulsion is a two-phase system consisting of two immiscible liquids, where one liquid is dispersed as globules in the other. Emulsions can be oil-in-water or water-in-oil depending on the dispersed and continuous phases. Emulsions are used pharmaceutically for oral, rectal, topical, and injectable drug delivery to mask tastes/odors and enhance absorption. Emulsion stability depends on the emulsifying agent and preventing effects like creaming, flocculation, coalescence, cracking, and phase inversion.
The document provides an overview of pharmaceutical aerosols, including their definition, types, components, propellants, containers, valves, manufacturing process, and drug delivery to the lungs. Key points include:
- Aerosols contain active ingredients that are released as a fine dispersion upon activation of a valve. They are used for topical, nasal, oral, or inhalation applications.
- Components include propellants, containers, valves/actuators, and product concentrate. Common propellants are hydrocarbons, chlorofluorocarbons, compressed gases like carbon dioxide.
- Manufacturing involves filling containers with concentrate then propellant using pressure or cold filling to minimize contamination. Metered dose inhalers precisely deliver
This document provides information about pharmaceutical suspensions. It begins by defining a suspension as a disperse system where an insoluble solid internal phase is uniformly dispersed throughout an external liquid phase. Particle size is important for suspensions to be classified as coarse or colloidal. Suspensions differ from solutions in that particles remain dispersed rather than dissolving. Sedimentation occurs over time due to particle size and density. Suspending agents are added to prevent sedimentation by increasing viscosity. The document discusses formulation, applications, advantages, and disadvantages of suspensions.
This document discusses disperse systems, which are mixtures where one substance is dispersed throughout another. It defines three main types of disperse systems: true solutions (particles <1 nm), colloidal dispersions (particles 1 nm to 500 nm), and heterogeneous dispersions (particles >500 nm). It provides characteristics of each type, such as visibility of particles, ability to pass through filters or membranes, sedimentation rates, and thermal motion of particles. The document also classifies disperse systems based on the state of the dispersed and continuous phases (gas, liquid, solid) and lists some key properties like colligative effects, diffusion rates, optical properties, and methods of separation.
This document provides information about pharmaceutical suspensions. It defines a suspension as a coarse dispersion where an insoluble solid active ingredient is uniformly dispersed throughout an external aqueous or non-aqueous liquid phase. Suspensions are formulated when drugs are insoluble, to mask bitter tastes, increase stability, or achieve sustained release. Key factors in formulating stable suspensions include particle size, shape, wettability, and use of suspending agents to decrease interparticle attraction and impart viscosity. Proper manufacturing controls suspension quality.
1) An emulsion is an unstable mixture of two immiscible liquids, where one liquid is dispersed as globules in the other liquid. Emulsions can be O/W (oil in water) or W/O (water in oil) types.
2) Pharmaceutical emulsions are used to deliver unpleasant tasting drugs, provide slow release of water-soluble drugs, and enhance absorption of oil-soluble drugs.
3) The key steps in formulating an emulsion are selecting an emulsifying agent based on its HLB value, adding preservatives and antioxidants, and using methods like trituration or the bottle method to prepare the emulsion.
Size separation, also known as screening or sieving, involves separating particles into two or more portions based on differences in particle size, shape, and density. This is done using screening surfaces with meshes of different sizes. Common methods of size separation include sieving using oscillation, vibration, gyration, brushing, or centrifugal force to separate particles. Size separation is useful for obtaining specific particle size ranges for applications like tablet and capsule production.
Pharmaceutical powders are solid dosage forms containing one or more drugs in finely divided form, with or without excipients. They have advantages like faster onset of action compared to other oral solid dosage forms. Powders are classified based on their intended use and formulation. They include bulk powders, simple/compound powders enclosed in papers or capsules, and compressed powders made into tablets. Proper mixing and packaging is important for powder formulations to ensure uniform drug content and stability.
This document discusses pharmaceutical incompatibilities, which occur when two or more ingredients in a prescription interact in an undesirable way that affects the safety, efficacy, appearance or stability of the medication. It defines three main types of incompatibilities - physical, chemical and therapeutic. Physical incompatibilities involve changes in properties like color, odor or viscosity. Chemical incompatibilities occur due to reactions like oxidation or acid-base interactions. Therapeutic incompatibilities modify a drug's intended pharmacological effects. The document provides examples and explanations of specific incompatibilities within each category.
This document discusses powders and granules used in pharmaceutical formulations. It defines powders and granules and discusses their advantages. Particle size and shape are described. Hard and soft gelatin capsules are summarized, including their manufacturing and filling methods. Sustained release and enteric coated capsules are briefly outlined. Microencapsulation techniques like coacervation and pan coating are introduced. Spray drying is also mentioned as a microencapsulation method.
Construction and working of silverson emulsifierRajdeepaKundu
The document describes the construction and working of a Silverson emulsifier. It consists of a head attached to a central shaft powered by a motor. The head contains turbine blades surrounded by a perforated mesh. Liquids are sucked into the head and subjected to intense mixing by the high-speed blades. This creates small emulsion globules that exit through the mesh openings, producing a fine emulsion. The Silverson emulsifier provides advantages like rapid mixing, particle size reduction, and homogenization through its high-shear action. Occasional clogging of the mesh pores is its main disadvantage.
An emulsion consists of two immiscible liquids, where one liquid is dispersed as fine droplets in the other. Emulsions can be oil-in-water or water-in-oil depending on which liquid is the continuous and dispersed phases. Multiple emulsions containing water and oil droplets are also possible. Emulsions are used orally, topically, and parenterally in pharmaceutical products. Stability is achieved through emulsifying agents which reduce interfacial tension between phases. The type of emulsion depends on the solubility of the emulsifying agent used.
This document provides information about emulsions, including:
1. Emulsions are biphasic liquid preparations containing two immiscible liquids, one dispersed as globules in the other with an emulsifying agent. There are two types: oil-in-water and water-in-oil.
2. Various tests can identify the emulsion type, like the dilution test. Stability is important and factors like creaming, sedimentation, cracking can cause instability.
3. The stability of emulsions depends on factors like chemical decomposition, physical changes, microbial growth, and phase inversion. Proper formulation and storage conditions can help minimize instability.
This document discusses ointments, which are semi-solid topical dosage forms used for therapeutic, protective, or cosmetic purposes. Ointments are greasy preparations containing 80% oil and 20% water that are applied to the skin or mucous membranes. They can contain dissolved, emulsified, or suspended drug ingredients. Ointments are classified based on penetration (epidermic, endodermic, diadermic) or therapeutic use (antibiotic, antifungal, anti-inflammatory). Ideal ointment bases are inert, compatible with skin pH, emollient, and release medication readily. Common bases include oleaginous (petrolatum, hard paraffin, liquid paraffin
Test for identification of type of emulsionSantuMistree4
Four tests are used to identify oil-in-water (O/W) and water-in-oil (W/O) emulsions: the dilution test, dye test, conductivity test, and fluorescence test. The dilution test identifies the emulsion type based on whether it dilutes easily with water or oil. The dye test observes emulsion droplets under a microscope after adding an oil-soluble dye. If the continuous phase is colored and droplets are clear, it is a W/O emulsion; if droplets are colored and the continuous phase is clear, it is an O/W emulsion. The conductivity test uses electrodes - if a bulb glows, it is an O/W emulsion, and if not, it is a
This document discusses the evaluation of semi-solid dosage forms. It defines semi-solids and classifies them into different types including ointments, creams, pastes, poultices, gels, and plasters. It describes the key characteristics and uses of each type. The document also covers important ingredients for semi-solids, including bases, and methods for evaluating different properties of semi-solids like penetration rate, absorption, rheology, biological testing, drug content, viscosity, and spreadability.
An emulsion is an unstable mixture of two immiscible liquids stabilized by an emulsifying agent. The document defines emulsions and describes different types including oil-in-water, water-in-oil, multiple, and microemulsions. Methods for preparing emulsions like the continental, English, and bottle methods are outlined. Advantages of emulsions include masking unpleasant tastes, enabling oral or parenteral administration of insoluble compounds, and providing sustained release. However, emulsions are thermodynamically unstable and require proper formulation to avoid issues like creaming or cracking.
This document discusses coarse dispersion suspensions. It defines suspensions as heterogeneous systems with two phases, a solid dispersed phase and a liquid continuous phase. The key points covered include:
- Classifying suspensions based on particle size as coarse, colloidal, or molecular dispersions.
- Theories behind sedimentation behavior, Brownian motion, and electrokinetic properties that impact suspension stability.
- Factors that influence flocculation vs deflocculation like zeta potential, electrolyte concentration, and addition of surfactants or polymers.
- DLVO theory explaining the balance of attractive van der Waals forces and repulsive electrostatic forces between particles.
- How temperature changes can impact physical
This document presents information about emulsions by Anirban Barman for his third year pharmacy course. It discusses the definition of emulsions, factors that affect emulsion stability such as cracking, creaming, and phase inversion. Cracking is the separation into two layers due to globule coalescence. Creaming is the upward movement of dispersed globules, affected by properties like density, viscosity, and temperature based on Stokes' law. Phase inversion is a change from one emulsion type to another, like oil-in-water to water-in-oil. Maintaining emulsion stability is important for ensuring product quality until expiration.
This document discusses emulsions and factors that influence their physical stability. Emulsions are biphasic systems containing both oil and water phases. Emulsifying agents stabilize emulsions by preventing globule coalescence. Stability depends on globule size, viscosity, density differences between phases, and properties of the interface film formed by emulsifying agents. Physical instability can occur via flocculation, creaming, coalescence, and breaking. Phase inversion is also discussed. Methods for evaluating and improving stability include assessing phase separation, globule size, and centrifugation testing. The document outlines preparation of emulsions on small and large scales.
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.
An emulsion is a two-phase system consisting of two immiscible liquids, where one liquid is dispersed as globules in the other. Emulsions can be oil-in-water or water-in-oil depending on the dispersed and continuous phases. Emulsions are used pharmaceutically for oral, rectal, topical, and injectable drug delivery to mask tastes/odors and enhance absorption. Emulsion stability depends on the emulsifying agent and preventing effects like creaming, flocculation, coalescence, cracking, and phase inversion.
The document provides an overview of pharmaceutical aerosols, including their definition, types, components, propellants, containers, valves, manufacturing process, and drug delivery to the lungs. Key points include:
- Aerosols contain active ingredients that are released as a fine dispersion upon activation of a valve. They are used for topical, nasal, oral, or inhalation applications.
- Components include propellants, containers, valves/actuators, and product concentrate. Common propellants are hydrocarbons, chlorofluorocarbons, compressed gases like carbon dioxide.
- Manufacturing involves filling containers with concentrate then propellant using pressure or cold filling to minimize contamination. Metered dose inhalers precisely deliver
This document provides information about pharmaceutical suspensions. It begins by defining a suspension as a disperse system where an insoluble solid internal phase is uniformly dispersed throughout an external liquid phase. Particle size is important for suspensions to be classified as coarse or colloidal. Suspensions differ from solutions in that particles remain dispersed rather than dissolving. Sedimentation occurs over time due to particle size and density. Suspending agents are added to prevent sedimentation by increasing viscosity. The document discusses formulation, applications, advantages, and disadvantages of suspensions.
This document discusses disperse systems, which are mixtures where one substance is dispersed throughout another. It defines three main types of disperse systems: true solutions (particles <1 nm), colloidal dispersions (particles 1 nm to 500 nm), and heterogeneous dispersions (particles >500 nm). It provides characteristics of each type, such as visibility of particles, ability to pass through filters or membranes, sedimentation rates, and thermal motion of particles. The document also classifies disperse systems based on the state of the dispersed and continuous phases (gas, liquid, solid) and lists some key properties like colligative effects, diffusion rates, optical properties, and methods of separation.
This document provides information about pharmaceutical suspensions. It defines a suspension as a coarse dispersion where an insoluble solid active ingredient is uniformly dispersed throughout an external aqueous or non-aqueous liquid phase. Suspensions are formulated when drugs are insoluble, to mask bitter tastes, increase stability, or achieve sustained release. Key factors in formulating stable suspensions include particle size, shape, wettability, and use of suspending agents to decrease interparticle attraction and impart viscosity. Proper manufacturing controls suspension quality.
1) An emulsion is an unstable mixture of two immiscible liquids, where one liquid is dispersed as globules in the other liquid. Emulsions can be O/W (oil in water) or W/O (water in oil) types.
2) Pharmaceutical emulsions are used to deliver unpleasant tasting drugs, provide slow release of water-soluble drugs, and enhance absorption of oil-soluble drugs.
3) The key steps in formulating an emulsion are selecting an emulsifying agent based on its HLB value, adding preservatives and antioxidants, and using methods like trituration or the bottle method to prepare the emulsion.
Size separation, also known as screening or sieving, involves separating particles into two or more portions based on differences in particle size, shape, and density. This is done using screening surfaces with meshes of different sizes. Common methods of size separation include sieving using oscillation, vibration, gyration, brushing, or centrifugal force to separate particles. Size separation is useful for obtaining specific particle size ranges for applications like tablet and capsule production.
Pharmaceutical powders are solid dosage forms containing one or more drugs in finely divided form, with or without excipients. They have advantages like faster onset of action compared to other oral solid dosage forms. Powders are classified based on their intended use and formulation. They include bulk powders, simple/compound powders enclosed in papers or capsules, and compressed powders made into tablets. Proper mixing and packaging is important for powder formulations to ensure uniform drug content and stability.
This document discusses pharmaceutical incompatibilities, which occur when two or more ingredients in a prescription interact in an undesirable way that affects the safety, efficacy, appearance or stability of the medication. It defines three main types of incompatibilities - physical, chemical and therapeutic. Physical incompatibilities involve changes in properties like color, odor or viscosity. Chemical incompatibilities occur due to reactions like oxidation or acid-base interactions. Therapeutic incompatibilities modify a drug's intended pharmacological effects. The document provides examples and explanations of specific incompatibilities within each category.
This document discusses powders and granules used in pharmaceutical formulations. It defines powders and granules and discusses their advantages. Particle size and shape are described. Hard and soft gelatin capsules are summarized, including their manufacturing and filling methods. Sustained release and enteric coated capsules are briefly outlined. Microencapsulation techniques like coacervation and pan coating are introduced. Spray drying is also mentioned as a microencapsulation method.
Construction and working of silverson emulsifierRajdeepaKundu
The document describes the construction and working of a Silverson emulsifier. It consists of a head attached to a central shaft powered by a motor. The head contains turbine blades surrounded by a perforated mesh. Liquids are sucked into the head and subjected to intense mixing by the high-speed blades. This creates small emulsion globules that exit through the mesh openings, producing a fine emulsion. The Silverson emulsifier provides advantages like rapid mixing, particle size reduction, and homogenization through its high-shear action. Occasional clogging of the mesh pores is its main disadvantage.
An emulsion consists of two immiscible liquids, where one liquid is dispersed as fine droplets in the other. Emulsions can be oil-in-water or water-in-oil depending on which liquid is the continuous and dispersed phases. Multiple emulsions containing water and oil droplets are also possible. Emulsions are used orally, topically, and parenterally in pharmaceutical products. Stability is achieved through emulsifying agents which reduce interfacial tension between phases. The type of emulsion depends on the solubility of the emulsifying agent used.
This document provides information about emulsions, including:
1. Emulsions are biphasic liquid preparations containing two immiscible liquids, one dispersed as globules in the other with an emulsifying agent. There are two types: oil-in-water and water-in-oil.
2. Various tests can identify the emulsion type, like the dilution test. Stability is important and factors like creaming, sedimentation, cracking can cause instability.
3. The stability of emulsions depends on factors like chemical decomposition, physical changes, microbial growth, and phase inversion. Proper formulation and storage conditions can help minimize instability.
Emulsion and emulsion method and types of emulsion (Physical Pharmacy)ZubairAhmed429283
This document provides an overview of emulsions, including their definition, types, advantages/disadvantages, identification tests, emulsifying agents, theories of emulsification, and methods of preparation and stability. Key points include that emulsions are mixtures of immiscible liquids stabilized by emulsifying agents, the main types are oil-in-water and water-in-oil emulsions, and their stability depends on a balance of attractive and repulsive forces between droplets. Identification tests distinguish emulsion types based on properties like dye solubility, electrical conductivity, and fluorescence under UV light.
1. The document discusses pharmaceutical emulsions, including definitions, classification, theories of emulsification, additives, and manufacturing methods.
2. Key topics covered include the classification of emulsions as oil-in-water or water-in-oil, factors that influence emulsion stability such as particle size and creaming, and common emulsifying agents like surfactants and hydrocolloids.
3. Methods for manufacturing emulsions on small and large scales are presented, such as the 4:2:1 extemporaneous method and use of a hand homogenizer to reduce droplet size.
aqueous one known as a direct emulsion. Stabilization of O/W emulsion is often performed with hydrophilic-hydrophobic particles. The hydrophilic end of the emulsifier molecule has an affinity for water, and the hydrophobic end is drawn to the fat/oil. Vigorously mixing the emulsifier with the water and oil creates a stable emulsion. For example, milk is oil in the water type of emulsion. In this mixture, fat globules are dispersed in the water.
Emulsion water in oil (W/O) is composed of an aqueous phase dispersed in the oil phase. A water-in-oil emulsion is much fattier than a direct emulsion. Margarine is a water-in-oil emulsion.
Other emulsions, such as oil in water in oil, or water in oil in water, exist as well. Blood is also an emulsion consisting of negatively charged colloidal particles, which are albuminoid substances.
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Issues of Concern
Emulsions are a sub-class of colloids, which are two-phase systems of matter.
Although the terms colloid and emulsion are sometimes used indistinctly, emulsion applies only when both dispersed, and continuous phases are liquids. A colloid is a mixture of a compound that is in a solid, liquid, or gas state and a liquid. The critical difference between a colloid and an emulsion is that colloid can form when any state of matter (solid, gas, or liquid) combine with a liquid. In contrast, the emulsion has two liquid components that are initially immiscible with each other.
Emulsions, as liquids, do not demonstrate a static internal structure. Emulsions are thermodynamically unstable as both the dispersed and continuous phases can revert as separate phases, oil, and water, by fusion or the coalescing of droplets. Industries use emulsifying agents, eg, surfactants, to maintain a static structure.[1]
Usually, the phase in which the surfactant exhibits the greatest solubility is the continuous phase. Thus, hydrophilic surfactants foster O/W emulsions, whereas lipophilic surfactants promote W/O emulsions.
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Clinical Significance
Emulsions are frequently used in pharmaceuticals, personal hygiene products, and cosmetics. These are usually oil and water emulsions, albeit dispersed. These emulsions are called creams, ointments, balms, pastes, films, or liquids, depending on their oil-to-water ratios, the addition of other additives, and their intended administration route. Emulsions allow the encapsulation of an active ingredient in the dispersed phase to protect it from degradation and preserve its activity in a sustained manner. They are used to make medications more palatable, to improve their effectiveness via dosage control of active ingredients, and to provide better aesthetics for topical drugs such as ointments.
Intravenous and parenteral emulsions may be used for nutritive therapy applications when a patient is unable to consume food or receive nutrition. Fat emulsions serve as dietary complements for patients who cannot get the required fat solely from their diet. The compound may be given as
An emulsion is a dispersion of one liquid (the dispersed phase) as globules within another liquid (the continuous phase) in which it is immiscible. Emulsions are thermodynamically unstable and require an emulsifying agent to stabilize the system. There are two main types of emulsions - oil-in-water (O/W) emulsions where oil is the dispersed phase and water the continuous phase, and water-in-oil (W/O) emulsions where water is the dispersed phase and oil the continuous phase. Emulsions can be prepared using various methods depending on the scale and ingredients, such as the continental/dry gum method, English/wet gum method, or bottle method
This document discusses emulsions, which are biphasic systems consisting of two immiscible liquids, one dispersed as droplets in the other. An emulsifying agent is needed to stabilize the system and prevent separation. There are two main types of emulsions: oil-in-water, where oil is the dispersed phase, and water-in-oil, where water is dispersed. Multiple emulsions contain emulsions dispersed within another liquid. Emulsions can be used to deliver drugs, vitamins, and actives to the body. The mechanisms by which emulsifying agents stabilize emulsions involve reducing interfacial tension, forming protective films at the oil-water interface, and imparting charges to globules.
This document discusses specialized pharmaceutical emulsions. It defines emulsions as unstable systems where one liquid is dispersed as globules in another liquid stabilized by emulsifying agents. The two main types are oil-in-water and water-in-oil emulsions. Multiple emulsions contain both water-in-oil and oil-in-water emulsions. Various methods are described for producing emulsions including mechanical and solvent evaporation techniques. Emulsifying agents lower the interfacial tension between the liquids to form stable emulsions. Potential applications include drug delivery, vaccines, and products for pulmonary, dermal, and oral administration.
This document provides an overview of pharmaceutical emulsions. It defines emulsions as dispersions of one liquid in another immiscible liquid, stabilized by an emulsifying agent. The key topics covered include the classification of emulsions as oil-in-water or water-in-oil, theories of emulsification, common emulsifying agents like surfactants and hydrocolloids, and factors affecting the stability of emulsions such as flocculation and creaming. Pharmaceutical applications of emulsions include lotions, creams, and ointments.
This document discusses emulsions, including their introduction, types, emulsifying agents, methods of preparation, tests for emulsion types, stability, phase inversion, and breaking. An emulsion is a dispersion of small liquid globules within another immiscible liquid, classified as oil-in-water or water-in-oil emulsions. Emulsions are stabilized using emulsifying agents like carbohydrates, proteins, alcohols, or surfactants. Their stability depends on factors like interfacial film properties, electrical barriers, viscosity, droplet size distribution, and temperature. Phase inversion can occur by changing the order of addition, emulsifier properties, or phase ratios.
An emulsion is an unstable mixture of two immiscible liquids, where one liquid is dispersed as globules in the other liquid. Emulsions can be oil-in-water or water-in-oil depending on the continuous and dispersed phases. Surfactants are needed to stabilize emulsions by lowering surface tension at the interface between the liquids. The document discusses different types of emulsifiers including surface-active agents, hydrocolloids, and solid particles that stabilize emulsions through monomolecular or multimolecular film formation. It also covers emulsion characterization, applications in pharmaceutical products, and factors affecting emulsion stability.
Emulsions are mixtures of two or more liquids where one liquid is dispersed as droplets in the other liquid. There is a dispersed phase and a continuous phase. Emulsions can be classified as oil-in-water (O/W), water-in-oil (W/O), or multiple emulsions. Emulsions are stabilized using emulsifying agents which lower the interfacial tension between the phases. Common emulsifying agents include carbohydrates, proteins, and alcohols. Emulsions are used to deliver poorly water-soluble drugs and provide benefits like masking unpleasant tastes, sustained release, and dermal delivery in cosmetics and topicals. However, emulsions are
This document discusses pharmaceutical emulsions. It defines an emulsion as consisting of two immiscible liquids, one dispersed as droplets in the other. Emulsions are stabilized by emulsifying agents. Pharmaceutical applications of emulsions include oral, rectal, topical, and intramuscular administration. Different types of emulsions like O/W and W/O are described. Factors affecting emulsion stability and types of instabilities are outlined. Methods for emulsification, preservation, and packaging are also summarized.
This presentation consists of the info about the pharmaceutical emulsions , definition, types,preparations,methods,formulation,emulsifying agents ....
this presentation is very useful for the b.pharm students for a brief idea ...
This document provides an overview of emulsions and emulsifying agents. It begins by defining an emulsion as a biphasic system consisting of two immiscible liquids where one liquid is dispersed as droplets in the other. Emulsions are thermodynamically unstable and require emulsifying agents to stabilize them. The document then discusses Bancroft's rule which states that the phase in which the emulsifying agent is more soluble will be the continuous phase. Finally, it provides examples of natural, semi-synthetic, and synthetic emulsifying agents and how their HLB values determine whether they are suitable for water-in-oil or oil-in-water emulsions.
This document discusses emulsions, including definitions, types, formulation, and applications. It defines an emulsion as a thermodynamically unstable mixture of two immiscible liquids stabilized by an emulsifying agent. The main types discussed are simple/macroemulsions (oil-in-water and water-in-oil), multiple emulsions (e.g. water-in-oil-in-water), and microemulsions. Emulsifying agents help stabilize emulsions by reducing interfacial tension or forming protective films. Various natural and synthetic agents are classified and their functions explained. Pharmaceutical applications of emulsions include oral, parenteral, and topical formulations.
An emulsion is a dispersion of one liquid into another immiscible liquid. The key types are oil-in-water (O/W) and water-in-oil (W/O) emulsions. Emulsions have various pharmaceutical applications like masking unpleasant tastes and enhancing drug absorption. Emulsion stability and type depend on factors like the emulsifying agent used, its HLB value, and emulsion preparation method. Common tests are used to identify the emulsion type and stability must be ensured through proper preservation, packaging, and storage.
This document discusses pharmaceutical emulsions. It defines emulsions as mixtures of two immiscible liquids, with one liquid dispersed as droplets in the other. The document covers types of emulsions like oil-in-water and water-in-oil, advantages and disadvantages, identification tests, emulsifying agents, theories of emulsification, methods of preparation, and factors affecting stability.
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2. Emulsions:
¡ Definition: It is thermodynamically unstable
system consisting of at least two immiscible
liquid phases one of which is dispersed as
globules (the dispersed phase) in the other
liquid phase (the continuous phase) stabilized
by presence of emulsifying agent.
To stabilize these
droplets, emulsifying
agent should be added
-Particle diameter of dispersed phase (Internal phase) ranged from
0.1 to 10 um.
3. Pharmaceutical applications of
emulsions:
¡ 1. They can mask the bitter taste and odor of drugs,
e.g. castor oil, cod-liver oil etc.
¡ 2. They can be used to prolong the release of the drug
thereby providing sustained release action.
¡ 3. Essential nutrients like carbohydrates, fats and
vitamins can all be emulsified and can be administered
to bed ridden patients as sterile intravenous
emulsions.
¡ 4. Emulsions provide protection to drugs which are
susceptible to oxidation or hydrolysis.
¡ 5. Intravenous emulsions of contrast media have been
developed to assist in diagnosis.
¡ 6. Emulsions are used widely to formulate externally
used products like lotions, creams, liniments etc.
4. Emulsions:
¡ Types Of Emulsions:
1- Oil in water emulsions
2- Water in oil emulsions
3- Multiple emulsions (O/W/O) or (W/O/W)
4- Microemulsions
5. DIFFERENCE BETWEEN O/W AND W/O
EMULSIONS:
(o/w) (w/o)
Water is the dispersion medium and
oil is the dispersed phase
Oil is the dispersion medium and
water is the dispersed phase
non greasy and easily removable
from the skin
greasy and not water washable
used externally to provide cooling
effect e.g. vanishing cream
used externally to prevent
evaporation of moisture from the
surface of skin e.g. Cold cream
preferred for internal use as bitter
taste of oils can be masked.
preferred for external use like
creams.
7. Microemulsions:
¡ clear, stable, liquid mixtures of oil, water and surfactant,
frequently in combination with a cosurfactant.
¡ In contrast to ordinary emulsion, microemulsions form
upon simple mixing of the components and do not
require the high shear conditions generally used in the
formation of ordinary emulsions.
¡ The two basic types of microemulsions are (o/w) and
(w/o).
¡ Unlike the common macroemulsion in that:
1- Appear as clear transparent solution.
2- Diameter of internal phase droplets ranged between
10-200nm
3-Thermodynamically stable
9. Tests Used To Identify Emulsion Type:
¡ Dilution test: based on the solubility of external phase
of emulsion.
- o/w emulsion can be diluted with water.
- w/o emulsion can be diluted with oil.
10. Tests Used To Identify Emulsion Type:
¡ Conductivity Test:
¡ water is good conductor of electricity whereas
oil is non-conductor. Therefore, continuous
phase of water runs electricity more than
continuous phase of oil.
11. Tests Used To Identify Emulsion Type:
¡ Dye-Solubility Test:
¡ when an emulsion is mixed with a water soluble
dye such as amaranth and observed under the
microscope.
¡ if the continuous phase appears red, then it
means that the emulsion is o/w type as water is
the external phase
¡ if the scattered globules appear red and
continuous phase colorless, then it is w/o type.
12. Tests Used To Identify Emulsion Type:
¡ Fluorescence test: oils give fluorescence
under UV light, while water doesn’t. Therefore,
O/W emulsion shows spotty pattern while W/O
emulsion fluoresces.
13. Emulsifying agents:
¡ Emulsifier or surface active agent (SAA) is
molecule which has two parts, one is
hydrophilic and the other is hydrophobic.
Upon the addition of SAA, it tends to form
monolayer film at the oil/water interface.
14. Mechanism of action of emulsifying
agents:
¡ When two immiscible liquids are agitated
together so that one of the liquids is dispersed
as small droplets in the other.
To prevent coalescence between globules, it is
necessary to use emulsifying agent.
15.
16. Proposed mechanism
Example
Type of film
- Coherent monomolecular film
- flexible film formed by SAA,
- depend on lower the γo/w ,
- can prepare o/w and w/o emulsion
SAA
(K laurate,
tween)
Synthetic
SAA
Monomolecular
- Strong rigid film formed, mostly by the
hydrocolloid,
- which produce o/w emulsion,
- γ is not reduced to any extent ,
- the stability due to strength of the
formed interfacial film
Hydrophilic
colloid
( acacia,
gelatin)
Multimolecular
-Film formed by solid particles that are
small in size compared to the droplet of
the dispersed phase.
- Particles must be wetted by both
phases in order to remain at the interface
and form stable film,
- can form o/w and w/o
Colloid clays
(bentonite,
Mg(oH)2)
Solid particles
17. Mechanism of action of emulsifying
agents:
¡ Monomolecular adsorption:
Rule of Bancroft: The type of the emulsion is a
function of the relative solubility of the
surfactant, the phase in which it is more soluble
being the continuous phase.
18. Classification of emulsifying agents:
¡ Emulsifying agent may be classifying into three groups:
1-Natural emulsifying agents:
- form monomolecular and multimolecular film
A-Those from vegetable source
as acacia - tragacanth- pectin- derivative of cellulose
B-Those from animal source
as gelatin- cholesterol –wool fat
Advantages: Non toxic and relatively inexpensive
Disadvantages:
-They show considerable batch to batch variation
- readily support M.O. growth
- susceptible to alcohol, electrolytes
19. Classification of emulsifying agents:
2- Finely divided solid:
¡ - as bentonite - Mg(OH)2
¡ forming a coherent film which physical prevents
coalescence of the dispersed
globules.
¡ - if the particles are: preferntially wetted by the
aqueous phase o/w emulsion
:preferntially wetted by the oil phase
w/o emulsion
20. Classification of emulsifying agents:
3- Synthetic emulsifying agents as:
- form monomolecular film
A- Anionic emulsifying agents
Alkali soap:
- e.g. sodium, potassium
and ammonium salts of fatty acids
- Form o/w emulsions
- in acidic condition precipitated Fatty acid
- For external use
- incompatible with polyvalent cations
21. Classification of emulsifying agents:
Soap of di/trivalent metal
- e.g. Cal oleate
- Promote w/o emulsions
Amine soaps: N(CH2CH2OH)3
- neutral pH
- incompatible with acids and high concentration of
electrolytes
- Produce o/w emulsion
Sulfated and sulfonated compound
- E.g.Sodium lauryl sulphate
- stable over high pH range
- o/w emulsions
22. Classification of emulsifying agents:
B- Cationic surfactants
¡ Quaternary ammonium compounds:
E.g. Cetyl trimethylammonium bromide (Cetrimide)
and benzalkonium chloride
¡ Disadvantages: Toxicity and irritancy
¡ Incompatible with anionic surfactants, polyvalent
anions
¡ unstable at high pH
¡ It has marked antibacterial and anti infective
properties
23. Classification of emulsifying agents:
C- Nonionic surfactants
¡ Low toxicity and irritancy so suitable for oral and Parenteral
administeration
¡ High degree of compatibility
¡ Less sensitive to change pH or to addition of electrolytes
¡ E.g. Tweens (polyethylene fatty acid ester) O/W
E.g. Span ( sorpitan fatty acid ester) W/O
D- Amphoteric surfactants
¡ charge depending on the pH of the system
low pH cationic
high pH anionic
¡ i.e. lecithin: used to stabilize i.v., fat emulsion
24. Hydrophile-Lipophile Balance (HLB):
¡ HLB: the ratio between the hydrophilic portion
of the molecule to the lipophilic portion of the
molecule.
¡ The higher the HLB of an agent the
more hydrophilic it is.
¡ Spans are lipophilic have low HLB.
¡ Tweens are hydrophilic have high HLB.
26. Hydrophile-Lipophile Balance (HLB):
¡ Calculation of HLB:
Griffin equation:
HLB = 20 (1 – S / A)
S: saponification number of the ester
A: the acid number of the fatty acid
Davis equation:
HLB = hydrophilic group number – lipophilic group number + 7
27. Methods of emulsion preparation:
¡ On small scale:
¡ Porcelain mortar and pestle
¡ On large scale:
Mechanical stirrer Colloid mill
Homogenizer
28. Proportions of Oil, Water and Gum
required for formation of primary
emulsion:
Proportions of:
Type of oil oil water gum
Fixed oil 4 2 1
Mineral oil 3 2 1
Volatile oil 2 2 1
29. Methods of emulsion preparation:
¡ Continental or dry gum method:
Emulsifier is triturated with the oil in perfectly
dry porcelain mortar
water is added at once
triturate immediately, rapidly and continuously
(until get a clicking sound and thick white cream is formed,
this is primary emulsion)
the remaining quantity of water is slowly added to form the
final emulsion
30. Methods of emulsion preparation:
¡ English or Wet Gum Method
triturate gum with water in a mortar
to form a mucilage
oil is added slowly in portions
the mixture is triturated
after adding all of the oil, thoroughly
mixed for several minute to form the primary emulsion
Once the primary emulsion has been formed remaining
quantity of water is added to make the final emulsion.
31. Methods of emulsion preparation:
¡ Bottle or Forbes Bottle Method
- It is extemporaneous preparation for volatile oils or oil with
low viscosity.
gum + oil (dry bottle)
Shake
water (volume equal to oil) is added in portions with vigorous
shaking to form primary emulsion
remaining quantity of water is added to make the final emulsion
32. Emulsion Stability:
¡ The instability of pharmaceutical emulsions
may be classified as the following:
a) Flocculation and creaming
b) coalescence and breaking
c) Phase inversion
d) Miscellaneous physical and chemical change
35. Emulsion Stability:
¡ Flocculation and creaming:
¡ Flocculation - The small spheres of oil join
together to form clumps or flocs which rise or
settle in the emulsion more rapidly than
individual particles.
¡ Creaming - it is a concentration of the floccules
of the internal phase formed upward or
downward layer according to the density of
internal phase.
37. Creaming:
¡ Stoke‘s equation included the factors that
affect the creaming process:
dx/dt = d2 (ρi-ρe)g/18η
dx/dt = rate of setting
D = diameter of particles
ρ = density of internal phase and external phase
g = gravitational constant
η = viscosity of medium
38. Creaming:
¡ Factors affect creaming:
1- Globule size:
2- The density of the internal and external phases:
* ↑globule size → ↑creaming
pi-pe = 0 dx/dt = 0
pi-pe = -ve [i.e.-ve velocity upward creaming ]
pi-pe =+ve [ downward creaming]
3- Gravity: const, However centrifugation is applied.
4- Viscosity: ↑→ ↓creaming
39. Strategies to reduce creaming:
Principle Method
Reduce droplet size (r) Homogenizer
Reduce density difference (Δ p) Add weighting agent are
oils that, have a density
greater than the density
of water
Increase continuous phase
viscosity (η)
Add thickening
or gelling agent e.g.
methylcellulose
40. Coalescence and Breaking:
¡ Coalescence is the process by which
emulsified particles merge with each to form
large particles.
¡ Breaking - Due to Coalescence and creaming
combined, the oil separates completely from
the water so that it floats at the top in a single,
continuous layer.
41. Major differences between creaming and
breaking:
Breaking
Creaming
Items
Separation of
emulsion to upward
oily layer and
downward aq layer
Formation of
upward or
downward layer
Definition
irreversible
Reversible
Reverersability
not reconstituting
Reconstitute
Agitation
destroyed
intact
Emulsifying
film around
particles
Complete fusion
Partial or no
coalescence
Internal phase
globules
in o/w if oil >74%
No or little
Effect of phase
volume ratio
42. Phase inversion:
¡ In phase inversion o/w type emulsion changes into w/o
type and vice versa.
¡ It is a physical instability.
¡ It may be brought about by:
1- the addition of an electrolyte e.g. addition of CaCl2 into
o/w emulsion formed by sodium stearate can be inverted to
w/o.
2- by changing the phase volume ratio
3- by temperature changes.
- Phase inversion can be minimized by:
1- using the proper emulsifying agent in adequate
concentration
2- keeping the concentration of dispersed phase between
30 to 60 %
3- storing the emulsion in a cool place.
43. Cracking
¡ When an emulsion cracks during preparation, i.e., the
primary emulsion does not become white but acquires
an oily translucent appearance.
¡ In such a case, it is impossible to dilute the emulsion
nucleus with water and the oil separates out.
¡ Cracking of emulsion can be due to:
1- addition of an incompatible emulsifying agent
e.g. monovalent soap + divalent soap
e.g. anionic + cationic emulsifying agent
2- chemical or microbial decomposition of emulsifying
agent
44. Cracking
e.g. alkali soaps decomposed by acids
e.g. monovalent soaps salted out by electrolytes such as
NaCl
e.g. nonionic emulsifying agents are incompatible with
phenols
e.g. alcohol precipitates gums and gelatin
3- exposure to increased or reduced temperature
4- Addition of common solvent
e.g. addition of a solvent in which the two phases are
soluble (alcohol)
45. Preservation Of Emulsions
¡ Preservation from microorganisms:
¡ Contamination due to microorganisms can
result in problems such as:
1- color and odor change
2- gas production
3- hydrolysis
4- pH change
5- breaking of emulsion
e.g. methyl, propyl and butyl parabens
e.g. organic acids such as ascorbic acid and benzoic
46. Preservation Of Emulsions
¡ Preservation from oxidation:
¡ Antioxidants can be used to prevent the
changes occurring due to atmospheric oxygen
such as rancidity.
¡ e.g.butylated hydroxyanisole (BHA)
e.g.butylated hydroxytoluene (BHT)
47. Quality control tests for Emulsions
1. Determination of particle size and particle
count:
- It is performed by optical microscopy and
Coulter counter apparatus.
2. Determination of viscosity:
- Determination of viscosity is done to assess the
changes that might take place during aging.
- The viscometers used: cone and plate
viscometers.
48. Quality control tests for Emulsions
- In case of o/w emulsions, flocculation of
globules causes an immediate increase in
viscosity. After this change, the consistency of
the emulsion changes with time.
- In case of w/o emulsions, the dispersed
phase particles flocculate quite rapidly
resulting in a decrease in viscosity, which
stabilizes after 5 to 15 days.
- As a rule, a decrease in viscosity with age
reflects an increase of particle size due to
coalescence.
49. Quality control tests for Emulsions
3. Determination of phase separation:
- Phase separation may be observed visually or by
measuring the volume of the separated phases.
4. Determination of electrophoretic properties:
- Determination of electrophoretic properties like zeta
potential is useful for assessing flocculation since
electrical charges on particles influence the rate of
flocculation.
- O/W emulsion having a fine particle size will exhibit low
resistance but if the particle size increase, then it
indicates a sign of oil droplet aggregation and instability.
50. Assessment of emulsion shelf life:
¡ Stress conditions employed for evaluating the
stability of emulsions:
1- Aging and temperature
- Cycling between two temperatures (4 and 45°C)
- At elevated temperature: accelerates the rate of
coalescence and creaming and this is coupled
with change in viscosity
temperature thin emulsion
Room temperature thick emulsion
- Freezing damage emulsion more than heating ?
Since, the solubility of emulsifiers is more
sensitive to freezing than heating.
51. Assessment of emulsion shelf life:
2- Centrifugation:
Centrifugation at 3750 rpm for 5 hours = effect
of gravity for one year.
3- Agitation:
¡ The following physical parameters are
evaluated to assess the effect of any of the
above stress conditions:
a· Phase separation
b· Viscosity
c· Electrophoretic properties
d· Particle size and particle count
52. Overview of the possible effects during emulsion centrifugation
for O/W and W/O emulsions
(a); flocculation (b), coalescence
(c), fractionation according to particle size distribution
(d), detection of the presence of a surfactant aggregate
(e) (promoting emulsion creaming by the depletion effect)