This document defines and describes emulsions. It states that an emulsion is an unstable mixture of two immiscible liquids stabilized by an emulsifying agent. Emulsions are classified as simple (macro) emulsions, multiple emulsions, or microemulsions. Simple emulsions can be oil-in-water or water-in-oil, while multiple emulsions contain both types simultaneously. Microemulsions are clear, stable mixtures with particle sizes less than 120nm. The document also discusses emulsifying agents, formulation components, stability issues like flocculation and creaming, and identification tests.
This document discusses mechanisms of emulsion instability and strategies for emulsion stabilization. It describes five mechanisms by which emulsions can break down: creaming, sedimentation, flocculation, coalescence, and phase inversion. It also explains the electrostatic and van der Waals forces that affect emulsion stability, including the electrical double layer and DLVO theory. Finally, it outlines various methods to stabilize emulsions, such as using emulsifiers, matching densities, reducing droplet size, modifying viscosity, and testing stability over time.
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 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 factors that can cause instability in emulsions over time during storage. The three main changes that can occur are cracking, creaming, and phase inversion. Cracking is the separation of phases and can result from changes in emulsifying agents, solvents, microbes, temperature, or creaming. Creaming is the upward movement of dispersed globules, which depends on globule size, density differences, viscosity, and storage temperature. Phase inversion is a change from one emulsion type to the other, such as oil-in-water to water-in-oil, brought on by electrolytes, phase volume ratios, temperature, or emulsifying agents. Proper packaging, labeling, and storage conditions can help promote emulsion
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 provides information about ointment as a semisolid dosage form. It defines ointments as semisolid preparations intended for external application with properties that allow them to cling to the application surface. The document discusses the composition of ointments including their bases, which can be oleaginous, absorption, water removable, or water soluble. It also covers the advantages and disadvantages of ointments as well as methods for their preparation, including incorporation and fusion methods. The selection of an appropriate base depends on factors like desired drug release and stability.
The document defines an emulsion as a mixture of two or more liquids that are normally immiscible. It then discusses the internal and external phases of emulsions, types of emulsions based on dispersed phase and size, advantages and disadvantages, identification tests, emulsifying agents, theories of emulsification, and factors that contribute to emulsion stability like interfacial tension. In summary, the key topics covered are the definition of emulsions, classification based on phase and size, tests to identify emulsion types, role of emulsifying agents, and theories to explain emulsion stabilization mechanisms.
This document discusses mechanisms of emulsion instability and strategies for emulsion stabilization. It describes five mechanisms by which emulsions can break down: creaming, sedimentation, flocculation, coalescence, and phase inversion. It also explains the electrostatic and van der Waals forces that affect emulsion stability, including the electrical double layer and DLVO theory. Finally, it outlines various methods to stabilize emulsions, such as using emulsifiers, matching densities, reducing droplet size, modifying viscosity, and testing stability over time.
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 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 factors that can cause instability in emulsions over time during storage. The three main changes that can occur are cracking, creaming, and phase inversion. Cracking is the separation of phases and can result from changes in emulsifying agents, solvents, microbes, temperature, or creaming. Creaming is the upward movement of dispersed globules, which depends on globule size, density differences, viscosity, and storage temperature. Phase inversion is a change from one emulsion type to the other, such as oil-in-water to water-in-oil, brought on by electrolytes, phase volume ratios, temperature, or emulsifying agents. Proper packaging, labeling, and storage conditions can help promote emulsion
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 provides information about ointment as a semisolid dosage form. It defines ointments as semisolid preparations intended for external application with properties that allow them to cling to the application surface. The document discusses the composition of ointments including their bases, which can be oleaginous, absorption, water removable, or water soluble. It also covers the advantages and disadvantages of ointments as well as methods for their preparation, including incorporation and fusion methods. The selection of an appropriate base depends on factors like desired drug release and stability.
The document defines an emulsion as a mixture of two or more liquids that are normally immiscible. It then discusses the internal and external phases of emulsions, types of emulsions based on dispersed phase and size, advantages and disadvantages, identification tests, emulsifying agents, theories of emulsification, and factors that contribute to emulsion stability like interfacial tension. In summary, the key topics covered are the definition of emulsions, classification based on phase and size, tests to identify emulsion types, role of emulsifying agents, and theories to explain emulsion stabilization mechanisms.
This document discusses ointments, which are semisolid preparations intended for local or transdermal delivery of active substances for skin application. It defines ointments and describes their types, classifications based on penetration and therapeutic use, ideal properties of bases, methods of preparation including mechanical incorporation and fusion. It also discusses factors influencing dermal absorption such as skin and drug properties and the vehicle used. The document concludes that ointments have significant treatment potential and demand will continue to rise for dermatological products addressing skin diseases and protection.
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.
This document discusses emulsions. It defines an emulsion as a dispersion of small globules of one liquid distributed throughout another immiscible liquid. Emulsions are classified based on the dispersed phase as oil-in-water or water-in-oil, and based on droplet size as macroemulsions or microemulsions. Emulsifying agents are substances that stabilize emulsions by forming films at the liquid interfaces. Various natural, semi-synthetic, and synthetic agents are described. Methods for preparing emulsions include dry gum, wet gum, and bottle methods. Factors that cause emulsion instability like cracking and creaming are also outlined.
This document discusses suspensions, which are two-phase systems consisting of finely divided solid particles dispersed in a liquid vehicle. Suspensions can be classified based on administration route or particle size. They are useful for drugs with low solubility and can improve stability, release properties, and bioavailability compared to other dosage forms. However, suspensions are also prone to physical instability issues like sedimentation. The document outlines factors that affect sedimentation and strategies to improve suspension stability such as controlling particle size, viscosity, surface charge, and use of surfactants or flocculating agents. Wetting agents are also discussed which help disperse solid particles in the liquid vehicle by reducing surface tension.
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.
The document discusses theories of emulsification including definitions, methods of preparation, factors affecting stability, and mechanisms of emulsification. Specifically, it describes three methods for preparing emulsions: the continental/dry gum method, English/wet gum method, and bottle/Forbes bottle method. It also outlines physical instability markers like flocculation, creaming, coalescence, and breaking as well as the concept of phase inversion in emulsions. Various emulsifying agents are discussed including their mechanisms of action through monomolecular adsorption and film formation, multimolecular adsorption, or solid particle adsorption.
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
This document discusses dispersed systems such as emulsions, colloids, and suspensions. It begins by defining dispersed systems as particulate matter distributed throughout a continuous medium and classifies them based on particle size into molecular, colloidal, or coarse dispersions. The document then covers topics such as interfacial phenomenon, wetting, adsorption, surface active agents, micellar solubilization, and the use of these concepts in pharmacy. It provides details on emulsions, including the theories of emulsification, methods to determine emulsion type, emulsifying agents, and 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
Surfactants and their applications in pharmaceutical dosage formMuhammad Jamal
This presentation is very much helpful for the medical students,pharmacists, researchers and other health care providers. i hope it will provide important information regarding surfactants and their applications in pharmaceutical dosage forms.
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 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
This document discusses pharmaceutical creams. It defines what a cream is and describes the anatomy of skin. It outlines different types of creams including cleansing, vanishing, foundation, night, massage, hand, body, and all-purpose creams. It discusses the components and manufacturing processes of creams and provides examples of formulations. Finally, it covers the uses of creams and some novel advances in cream technology.
The document discusses Indian gum, also known as gum acacia or gum arabic. It is a dried exudate obtained from the stems and branches of the Acacia arabica tree. Chemically, it is a complex mixture of glycoproteins and polysaccharides. It is collected by making cuts in the bark of the tree, then dried and processed. Gum acacia is used extensively in pharmaceuticals as an emulsifier, thickening agent, and tablet binder. It is also used in food products and cosmetics for its adhesive and thickening properties.
This document defines and describes emulsions. An emulsion is an unstable mixture of two immiscible liquids stabilized by an emulsifying agent. Emulsions can be classified as simple (macro), multiple, or micro. Simple emulsions are oil-in-water or water-in-oil, while multiple emulsions contain both types simultaneously. Microemulsions are clear, thermodynamically stable mixtures containing oil, water, surfactant and sometimes cosurfactant. Emulsions require emulsifying agents, viscosity modifiers, preservatives and sometimes antioxidants for stability. Common emulsifying agents include surfactants, hydrocolloids, and finely divided solids. Instability can occur via flocc
This document defines an emulsion as an unstable system consisting of at least two immiscible liquid phases, one dispersed as globules in the other. Emulsions can be oil-in-water or water-in-oil, with particle sizes typically ranging from 0.1 to 100 μm. Emulsifying agents help stabilize emulsions by forming monomolecular or multi-molecular films at the oil-water interface to prevent globule coalescence. Common emulsifying agents include surface-active agents, hydrophilic colloids, and finely divided solids. The HLB system assists in selecting emulsifying agents based on their hydrophilic-lipophilic balance. Pharmaceutical applications of emulsions include
The document discusses different types of emulsions. It begins by defining an emulsion as a mixture of two or more immiscible liquids. It then describes four main types of emulsions: oil-in-water emulsions, water-in-oil emulsions, multiple emulsions (O/W/O and W/O/W), and microemulsions. The key differences between O/W and W/O emulsions are also summarized. Detection tests for identifying the type of emulsion are then outlined.
Suspension, interfacial properties of suspended particles, settling in suspensions, formulation of flocculated and deflocculated suspensions. Emulsions and theories of emulsification, microemulsion and multiple emulsions; Stability of emulsions, preservation of emulsions, rheological properties of emulsions.
The document discusses various types of instability that can occur in pharmaceutical emulsions, including flocculation, coalescence, creaming, breaking, deterioration by microorganisms, and physical/chemical changes. Flocculation involves droplets aggregating into larger units while coalescence occurs when droplets merge to form even larger droplets. Creaming is the rising of dispersed globules, and breaking refers to the complete separation of emulsion phases. Proper formulation, storage conditions, and addition of preservatives can help prevent these instability issues.
This document defines and describes emulsions. It states that an emulsion is a two-phase system consisting of two immiscible liquids where one liquid is dispersed as globules in the other with the help of an emulsifying agent and mechanical energy. The document discusses emulsion types including oil-in-water and water-in-oil. It also covers emulsion components, applications in pharmaceuticals, formulation, identification of emulsion type, selection of emulsifying agents, mechanisms of action, and factors affecting stability. The key points are emulsions are thermodynamically unstable systems requiring emulsifying agents and mechanical energy to form and maintain.
This document discusses ointments, which are semisolid preparations intended for local or transdermal delivery of active substances for skin application. It defines ointments and describes their types, classifications based on penetration and therapeutic use, ideal properties of bases, methods of preparation including mechanical incorporation and fusion. It also discusses factors influencing dermal absorption such as skin and drug properties and the vehicle used. The document concludes that ointments have significant treatment potential and demand will continue to rise for dermatological products addressing skin diseases and protection.
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.
This document discusses emulsions. It defines an emulsion as a dispersion of small globules of one liquid distributed throughout another immiscible liquid. Emulsions are classified based on the dispersed phase as oil-in-water or water-in-oil, and based on droplet size as macroemulsions or microemulsions. Emulsifying agents are substances that stabilize emulsions by forming films at the liquid interfaces. Various natural, semi-synthetic, and synthetic agents are described. Methods for preparing emulsions include dry gum, wet gum, and bottle methods. Factors that cause emulsion instability like cracking and creaming are also outlined.
This document discusses suspensions, which are two-phase systems consisting of finely divided solid particles dispersed in a liquid vehicle. Suspensions can be classified based on administration route or particle size. They are useful for drugs with low solubility and can improve stability, release properties, and bioavailability compared to other dosage forms. However, suspensions are also prone to physical instability issues like sedimentation. The document outlines factors that affect sedimentation and strategies to improve suspension stability such as controlling particle size, viscosity, surface charge, and use of surfactants or flocculating agents. Wetting agents are also discussed which help disperse solid particles in the liquid vehicle by reducing surface tension.
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.
The document discusses theories of emulsification including definitions, methods of preparation, factors affecting stability, and mechanisms of emulsification. Specifically, it describes three methods for preparing emulsions: the continental/dry gum method, English/wet gum method, and bottle/Forbes bottle method. It also outlines physical instability markers like flocculation, creaming, coalescence, and breaking as well as the concept of phase inversion in emulsions. Various emulsifying agents are discussed including their mechanisms of action through monomolecular adsorption and film formation, multimolecular adsorption, or solid particle adsorption.
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
This document discusses dispersed systems such as emulsions, colloids, and suspensions. It begins by defining dispersed systems as particulate matter distributed throughout a continuous medium and classifies them based on particle size into molecular, colloidal, or coarse dispersions. The document then covers topics such as interfacial phenomenon, wetting, adsorption, surface active agents, micellar solubilization, and the use of these concepts in pharmacy. It provides details on emulsions, including the theories of emulsification, methods to determine emulsion type, emulsifying agents, and 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
Surfactants and their applications in pharmaceutical dosage formMuhammad Jamal
This presentation is very much helpful for the medical students,pharmacists, researchers and other health care providers. i hope it will provide important information regarding surfactants and their applications in pharmaceutical dosage forms.
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 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
This document discusses pharmaceutical creams. It defines what a cream is and describes the anatomy of skin. It outlines different types of creams including cleansing, vanishing, foundation, night, massage, hand, body, and all-purpose creams. It discusses the components and manufacturing processes of creams and provides examples of formulations. Finally, it covers the uses of creams and some novel advances in cream technology.
The document discusses Indian gum, also known as gum acacia or gum arabic. It is a dried exudate obtained from the stems and branches of the Acacia arabica tree. Chemically, it is a complex mixture of glycoproteins and polysaccharides. It is collected by making cuts in the bark of the tree, then dried and processed. Gum acacia is used extensively in pharmaceuticals as an emulsifier, thickening agent, and tablet binder. It is also used in food products and cosmetics for its adhesive and thickening properties.
This document defines and describes emulsions. An emulsion is an unstable mixture of two immiscible liquids stabilized by an emulsifying agent. Emulsions can be classified as simple (macro), multiple, or micro. Simple emulsions are oil-in-water or water-in-oil, while multiple emulsions contain both types simultaneously. Microemulsions are clear, thermodynamically stable mixtures containing oil, water, surfactant and sometimes cosurfactant. Emulsions require emulsifying agents, viscosity modifiers, preservatives and sometimes antioxidants for stability. Common emulsifying agents include surfactants, hydrocolloids, and finely divided solids. Instability can occur via flocc
This document defines an emulsion as an unstable system consisting of at least two immiscible liquid phases, one dispersed as globules in the other. Emulsions can be oil-in-water or water-in-oil, with particle sizes typically ranging from 0.1 to 100 μm. Emulsifying agents help stabilize emulsions by forming monomolecular or multi-molecular films at the oil-water interface to prevent globule coalescence. Common emulsifying agents include surface-active agents, hydrophilic colloids, and finely divided solids. The HLB system assists in selecting emulsifying agents based on their hydrophilic-lipophilic balance. Pharmaceutical applications of emulsions include
The document discusses different types of emulsions. It begins by defining an emulsion as a mixture of two or more immiscible liquids. It then describes four main types of emulsions: oil-in-water emulsions, water-in-oil emulsions, multiple emulsions (O/W/O and W/O/W), and microemulsions. The key differences between O/W and W/O emulsions are also summarized. Detection tests for identifying the type of emulsion are then outlined.
Suspension, interfacial properties of suspended particles, settling in suspensions, formulation of flocculated and deflocculated suspensions. Emulsions and theories of emulsification, microemulsion and multiple emulsions; Stability of emulsions, preservation of emulsions, rheological properties of emulsions.
The document discusses various types of instability that can occur in pharmaceutical emulsions, including flocculation, coalescence, creaming, breaking, deterioration by microorganisms, and physical/chemical changes. Flocculation involves droplets aggregating into larger units while coalescence occurs when droplets merge to form even larger droplets. Creaming is the rising of dispersed globules, and breaking refers to the complete separation of emulsion phases. Proper formulation, storage conditions, and addition of preservatives can help prevent these instability issues.
This document defines and describes emulsions. It states that an emulsion is a two-phase system consisting of two immiscible liquids where one liquid is dispersed as globules in the other with the help of an emulsifying agent and mechanical energy. The document discusses emulsion types including oil-in-water and water-in-oil. It also covers emulsion components, applications in pharmaceuticals, formulation, identification of emulsion type, selection of emulsifying agents, mechanisms of action, and factors affecting stability. The key points are emulsions are thermodynamically unstable systems requiring emulsifying agents and mechanical energy to form and maintain.
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
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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.
An emulsion is a dispersion of one liquid in another in which globules of one liquid are dispersed throughout the other liquid. The document discusses various topics related to emulsions including definitions, types, theories, additives, methods of preparation, testing, stability, and applications. Large scale methods for manufacturing emulsions include stirrers, homogenizers, and colloid mills which reduce droplet size through various mechanical means like high pressure homogenization. Small scale methods include mixing oil and water directly by hand shaking or using handheld homogenizers. Factors like emulsifier type and concentration, energy input, and temperature control affect emulsion properties and stability over time.
An emulsion is a mixture of two or more liquids that are normally immiscible. Emulsions are part of a more general class of two-phase systems of matter called colloids.
The document discusses various types of mechanical equipment used to produce emulsions, including stirrers, homogenizers, and ultrasonic devices. Stirrers are suitable for low to moderate viscosity emulsions but not micro/nano emulsions. Homogenizers work by passing coarse emulsions through a small inlet at high pressure to break large globules into smaller, more uniform and stable ones. Ultrasonic devices use ultrasonic energy to force dispersions through an orifice to impinge on a vibrating blade, producing rapid vibrations and particle sizes down to microns. The key is applying shear forces like cutting, pressure changes and turbulence to reduce the internal phase into small droplets.
The document discusses emulsions, including definitions, classification, preparation methods, stability issues, and testing. Some key points:
- An emulsion is a biphasic liquid containing two immiscible liquids, one dispersed as minute globules in the other. The dispersed liquid is called the dispersed phase and the continuous liquid is the continuous phase.
- Emulsions can be oil-in-water (O/W) or water-in-oil (W/O) depending on which liquid is the dispersed phase. Emulsifying agents help stabilize emulsions by reducing interfacial tension.
- Common preparation methods include dry gum, wet gum, and bottle methods. Stability testing can identify
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.
This document provides an overview of disperse systems, including emulsions and suspensions. It discusses key concepts such as interfacial phenomena, wetting, adsorption, surfactants, and micelle formation. Theories of emulsification including electric double layer, phase volume, oriented wedge, and surface tension are presented. Methods for determining emulsion type including dilution, dye, conductivity, and fluorescence tests are described. Emulsifying agents and factors influencing emulsion stability are also summarized. Suspensions are defined as biphasic systems with solid particles between 0.5-5 microns dispersed in a liquid. Particle size and sedimentation theories are briefly covered.
Emulsions are thermodynamically unstable systems consisting of two immiscible liquid phases, one dispersed as globules in the other. In-process quality control tests are conducted to ensure emulsion stability and quality. Key tests include visual inspection, viscosity, particle size and distribution, phase volume ratio, and temperature fluctuations. Tests help identify and prevent instability issues like flocculation, creaming, coalescence, breaking, and phase inversion. Proper control of packaging materials and labels is also important for quality assurance.
This document discusses various techniques for enhancing drug solubility. It begins with an introduction to factors affecting drug solubility and processes of solubilization. Then it describes techniques such as co-solvency, use of surfactants, complexation, and solid state manipulation. Co-solvency uses water-miscible solvents to improve drug solubility. Surfactants form micelles above the critical micelle concentration that can solubilize drugs. Complexation with cyclodextrin can enhance aqueous solubility. Manipulating a drug's solid state, such as forming polymorphs, can also increase solubility. The document provides examples and mechanisms for each solubility enhancement technique.
Pharm Excipients suspending and emulsifying agentsSasidharRlc2
This document discusses suspending and emulsifying agents used in pharmaceutical formulations. It defines suspensions as systems with an insoluble internal phase dispersed uniformly throughout an external phase. Suspending agents prevent particle settling and aggregation, and increase viscosity. Examples include natural agents like acacia, semi-synthetic agents like carboxymethylcellulose, and inorganic salts like bentonite. Emulsions are unstable systems with one immiscible liquid dispersed as globules in another, stabilized by emulsifying agents. These agents reduce interfacial tension and form protective films to prevent coalescence. Examples of emulsifiers discussed include soaps, sulfates, quaternary ammonium compounds, and non-ionic surfactants like polysorbates.
An emulsion is a mixture of two immiscible liquids, where one liquid is dispersed as globules in the other. There are two types: oil-in-water (O/W) and water-in-oil (W/O). Emulsions have advantages like masking unpleasant tastes and sustained drug release, but are thermodynamically unstable with a short shelf life. Emulsions contain a dispersed internal phase and a continuous external phase, and emulsifying agents are used to stabilize the emulsion by reducing interfacial tension at the boundary between the two liquids.
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.
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2. DEFINATION :
• Emulsion is thermodynamically unstable mixture of two
essentially immiscible liquids .
OR
• Emulsion is a dispersion in which the dispersed phase is
composed of small globules of a liquid distributed
throughout a vehicle in which it is immiscible and
stabilized by emulsifying agent .
• one phase persists in droplet form called internal or
discontinuous or disperse phase and is surrounded by
an external or continuous phase .
4. Simple emulsion :
• Oil-in-water emulsion : Oil is internal phase and water is
external phase . Eg;Terpentine liniment
• Water-in-oil emulsion : water is internal phase and oil is
external phase . Eg;Butter
Multiple emulsion :
• Multiple emulsions are complex polydispersed systems where
both oil in water and water in oil emulsion exists
simultaneously which are stabilized by lipophillic and
hydrophilic surfactants respectively .
5. Microemulsion : Micro emulsions are clear,
thermodynamically stable, isotropic liquid mixtures of
oil, water and surfactant, frequently in combination with
a cosurfactant. The aqueous phase may contain salt(s)
and/or other ingredients, and the "oil" may actually be a
complex mixture of different hydrocarbons.
• Particle size = 10-120nm
• Viscosity : Less viscous compare to simple emulsion .
6. IDENTIFICATION TEST :
TEST OBSERVATION
Dilution test O/W emulsion diluted with water and W/O emulsion
diluted with oil .
Dye test Water-soluble(Amaranth) dye will dissolve in the
aqueous phase. Oil-soluble dye(scarlet red) will dissolve
in the oil phase.
CoCl2 filter paper test Filter paper deep into CoCl2 solution and dried (blue) .
Deep into emulsion, it gives pink color when O/W
emulsion is their .
Fluorescence test Under UV light,O/W exhibit dot pattern and W/O give
fluorescence throughout .
Conductivity test Electric current conducted by O/W emulsion.
7. THEORY OF EMULSIFICATION :
1 . Surface tension theory :
• According to the surface tension theory of
emulsification, the use of emulsifiers and stabilizers
lowers the interfacial tension of the two immiscible
liquids .
• Reducing the repellent force between the molecules.
Thus, the surface-active agents facilitate the breaking up
of large globules into smaller ones, which then have a
lesser tendency to reunite or coalesce.
8. 2 . Oriented-Wedge Theory :
• Mono molecular layers of emulsifying agents are cover
the droplet of the internal phase of the emulsion
• It is based on the presumption that certain emulsifying
agents orient themselves within a liquid according to
their solubility in that particular liquid .
9. 3 . Interfacial film theory :
• Emulsifying agent form thin film surrounding the
droplets of the internal phase .
• The film prevents the contact and the coalescence of the
dispersed phase .
11. EMULSIFYING AGENT :
• They are the substances added to an emulsion to
prevent the coalescence of the globules of the dispersed
phase. They are also known as emulgents or emulsifiers.
• They help in formation of emulsion by three
mechanisms.
- Reduction in interfacial tension
- Formation of a rigid interfacial film
- Formation of an electrical double layer
12.
13. • Characteristics :
Be stable .
Be compatible with other ingredients .
Be non – toxic .
Possess little odor , taste , or color .
Not interfere with the stability of efficacy of the
active agent .
14. Classification of Emulsifier :
1 . Synthetic :
Anionic surfactants :
• Negatively charged in aqueous solution .
• Widely used because of cost and performance
• Sodium lauryl sulfate commonly used to form O/W emulsion .
• Alkali hydroxide + Fatty acid Alkali metal soap (Sodium
oleate)
• Alkali earth metal soap (calcium oleate) produce stable W/O
emulsion because of low water solubility .
• Triethanolamine stearate produce stable O/W emulsions .
16. Non-ionic surfactants :
• Consist of (CH2CH2O)noH or OH as hydrophilic group and
exhibit variety of HLB which stabilize O/W or W/O
emulsions .
• Useful for oral and parenteral formulation bcz of their
low irritation and toxicity .
• Neutral nature so less sensitive to change pH of medium
and presence of electrolytes .
• Produce equally balanced HLB of hydrophilic and
hydrophobic surfactants .
17. • Eg; Span – not soluble in water and used for W/O
emulsions .
• Eg; Tween – soluble in water and used for O/W
emulsions .
18. Ampholytic surfactants :
• Possess both cationic and anionic groups in the same
molecule and dependent on pH of the medium .
• Lecithin is used for parenteral emulsion .
19. 2 . Auxiliary emulsifiers :
• Auxiliary emulsifying agents include those compounds
that are normally incapable themselves of forming
stable emulsion. They as thickening agents and help to
stabilize the emulsion .
20.
21. 3 . Natural emulsifier :
• Derived from plants and animal and hydrated lipophilic
colloids (hydrocolloids)
• No effect on interfacial tension
• Protective colloidal effect
22. Hydrocolloids :
• Form multimolecular film
• Promote O/W emulsion
• Do not cause appreciable lowering of surface tension
• Increase viscosity
24. Finely Divided Solids :
• Good emulsifier in combination with surfactants and/or
macromolecules that increase viscosity .
• Eg; Polar inorganic solid – Heavy metal hydroxide, non-
swelling clays and pigments . Polar solids wetted by
water in greater extent than oil phase .
Colloidal Clays : Bentonite,Veegum ,Magnesium
trisilicate
Metallic hydroxides : Magnesium hydroxide ,Aluminium
hydroxide
• Eg; Non-polar solid – Carbon or Glyceryl tristearate .
Non-polar solids wetted by oil phase .
25. VISCOSITY MODIFIER
• For W/O emulsions polyvalent metal soaps or high
melting waxes and resins in oil phase can be used to
increase viscosity .
• Greater volume of internal phase, greater viscosity .
• To control emulsion viscosity, 2 interacting effects must
be balanced .
1. Viscosity of O/W and W/O emulsion can increased by
reducing particle size of dispersed phase .
2. Flocculation or clumping which increase viscosity .
• Viscosity also increase with increse in age .
26. ANTIMICROBIAL PRESERVATIVES :
• Emulsion contain carbohydrates, proteins, sterols,
phosphatides which support growth of microorganism .
So that , preservatives necessary .
• Cause :
During production
During use
Poor quality raw material
Machine contamination
water
27. • Characteristics :
Less toxic
Stable to heat and storage
Chemically compatible
Reasonable cost
Acceptable taste, odor and color.
Effective against fungus, yeast, bacteria.
Available in oil and aqueous phase at effective level concentration.
Preservative should be in unionized state to penetrate the bacteria.
Not bind to other components of the emulsion .
28. • Eg ;
TYPE EXAMPLE CHARACTERISTICS
Acid and acid
derivatives
Benzoic acid and salts
Propionic acid and salts
Dehydroacetic acid
Antifungal agen
Alcohols Chlorobutanol
Phenoxy-2-ethanol
Eye preparation
Aldehyde Formaldehyde
Glutaraldehyde
Broad spectrum
Phenols Phenol
Cresol
Broad spectrum
Mercurials Phenylmercuric acetate Broad spectrum
29. ANTIOXIDENT
• Many drugs incorporated into emulsions are subjected
to autoxidation and resulting decomposition .
• Upon autoxidation, vegetable oils give rise to unpleasant
odour, appearance and taste .
• Autoxidation is free radical chain oxidation reaction . It
can be inhibited by absence of oxygen or free redical
chain breaker or by reducing agent .
32. FLOCCULATION :
• Flocculation is reversible aggregation of droplets of the
internal phase . It take place before, during and/or after
creaming .
• Cause of flocculation ; Insufficient amount of emulsifier .
• Types of flocculation depends on strength of interaction
between particles which is determined by ; chemical
nature of emulsifier, phase volume ratio, concentration
of dissolved substance especially electrolytes and ionic
emulsifiers .
• Eg; 2% hexadecane-in-water emulsion stabilized with
0.09% Aerosol , which is negatively charged surfactant,
remains deaggregated .
33. • A high internal phase volume, i.e. tight packing of
dispersed phase, tends to promote flocculation .
• The extent of flocculation of globules depends on ;
(a) globule size distribution.
(b) charge on the globule surface.
(c) viscosity of the external medium.
34. (a) Globule size distribution
• Uniform sized globules prevent flocculation.
• This can be achieved by proper size reduction process.
(b) Charge on the globule surface
• A charge on the globules exert repulsive forces with the
neighboring globules.
• This can be achieved by using ionic emulsifying agent, electrolytes
etc.
(c) Viscosity of the external medium.
• If the viscosity of the external medium is increased, the globules
become relatively immobile and flocculation can be prevented.
• This can be obtained by adding viscosity improving agents (bodying
agents or thickening agents) such as hydrocolloids or waxes.
35. CREAMING :
• Creaming is the upward movement of dispersed droplets of
emulsion relative to the continuous phase (due to the density
difference between two phases).
• Creaming is the concentration of globules at the top or bottom of
the emulsion.
• Droplets larger than 1 mm may settle preferentially to the top or
the bottom under gravitational forces.
• Creaming may also be observed on account of the difference of
individual globules (movement rather than flocs).
• It can be observed by a difference in color shade of the layers.
• It is a reversible process, i.e., cream can be re-dispersed easily by
agitation, this is possible because the oil globules are still
surrounded by the protective sheath of the emulsifier.
36. • Creaming results in a lack of uniformity of drug
distribution. This leads to variable dosage. Therefore,
the emulsion should be shaken thoroughly before use.
• Creaming is of two types, upward creaming and
downward creaming .
A B
37. A . Upward creaming, is due to the dispersed phase is less
dense than the continuous phase. This is normally
observed in o/w emulsions. The velocity of
sedimentation becomes negative.
B . Downward creaming occurs if the dispersed phase is
heavier than the continuous phase. Due to gravitational
pull, the globules settle down. This is normally observed
in w/o emulsions.
38. • Creaming is influenced by,
Globule size
Viscosity of the dispersion medium
Difference in the densities of dispersed phase and dispersion medium.
• Creaming can be reduced or prevented by:
1. Reducing the particle size by homogenization. Doubling the diameter of oil
globules increases the creaming rate by a factor of four.
2. Increasing the viscosity of the external phase by adding the thickening
agents such as methyl cellulose, tragacanth or sodium alginate.
3. Reducing the difference in the densities between the dispersed phase and
dispersion medium.
39. COALESCENCE :
• Coalescence is a growth process during which the emulsified
particles join to form larger particles . This indicates that
emulsion will separate completely or BREAK .
• Coalescence in flocculated or unflocculated emulsion
prevented by mechanical strength of interfacial barrier .
• Coalescence is observed due to:
Insufficient amount of the emulsifying agent.
Altered partitioning of the emulsifying agent.
Incompatibilities between emulsifying agents.
40. Brecking :
• Breaking is the destroying of the film surrounding the
particles.
• Separation of the internal phase from the external phase is
called breaking of the emulsion.
• This is indicated by complete separation of oil and aqueous
phases, is an irreversible process, i.e., simple mixing fails. It is
to re-suspend the globules into an uniform emulsion.
• In breaking, the protective sheath around the globules is
completely destroyed and oil tends to coalesce.
41. PHASE INVERSION :
• This involves the change of emulsion type from o/w to
w/o or vice versa.
• When we intend to prepare one type of emulsion say
o/w, and if the final emulsion turns out to be w/o, it can
be termed as a sign of instability.
43. PHASE SEPARATION
• The rate of phase separation after aging may be
observed visually or by measuring volume of separated
phase .
• The amount of coalescence depends on concentration
of emulsifier . If concentration raised to 2 or 5%, amount
of visible coalescence is negligible even after 2 yrs
storage .
• Phase separation determined by withdrawing small
amount of emulsion from top and bottom after some
period of storage and comparing composition of two
samples by analysis of water content, oil content .
44. VISCOSITY
• Viscosity measured by Brookfield viscometer.
• Viscosity increase with increase in age of emulsion .
• To achieve proper viscosity , vicosity modifier is added .
45. ZETA POTENTIAL
• Zeta potential measured by observing the movement of
particles under the influence of electric current .
• Zeta potential used to determine emulsion instability due to
flocculation .
• The measurement of electrical conductivity of o/w or w/o
emulsions determined with the aid of Pt electrodes .
• The conductivity depends on degree of dispersion . o/w
exhibit low resistence .
• If resistence increase then it is sign of aggregation and
instability .
46. PARTICLE SIZE
• Particle size of emulsion is measured by ;
• Microscopic method
• Coulter counter
• Electronic counting device
• Light scattering
49. APPLICATION
• Oral, rectal and topical administration of oils and oil-soluble
drugs.
• The unpleasant taste or odor can be masked by emulsification
• The absorption and penetration of medicament are enhanced
by emulsification
• Intramuscular injections of water soluble drugs or vaccine to
provide slow release
• The use of sterile stable i.v emulsion containing fats,
carbohydrates and vitamins as a potential nutrition .
50. PACKAGING
• Depending on the use, emulsions should be packed in suitable containers .
• Emulsions meant for oral use are usually packed in well filled bottles having
an air tight closure.
• Light sensitive products are packed in amber coloured bottles.
• For viscous emulsions, wide mouth bottles should be used.
• The label on the emulsion should mention that these products have to be
shaken thoroughly before use.
• External use products should clearly mention on their label that they are
meant for external use only.
• Emulsions should be stored in a cool place but refrigeration should be
avoided as this low temperature can adversely effect the stability of
preparation.