Emulsion
•
361 likes•120,598 views
An emulsion is an unstable mixture of two immiscible liquids stabilized by an emulsifying agent. Emulsions have various pharmaceutical applications including oral and topical drug delivery. The type of emulsion (e.g. oil-in-water, water-in-oil) depends on the relative solubility of the emulsifying agent. Emulsions can be prepared using different methods such as the dry gum, wet gum, or bottle methods. Drugs can be incorporated into emulsions during or after emulsion formation.
![Emulsion ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Recommended
More Related Content
What's hot
What's hot (20)
Viewers also liked
Viewers also liked (18)
Similar to Emulsion
Similar to Emulsion (20)
Recently uploaded
Recently uploaded (20)
Emulsion
- 1. Amit M Gupta Lecturer, Agnihotri College of Pharmacy, Wardha Emulsion
- 3. Emulsion A’. Two immisicble liquids, not emulsified; B’. An emulsion of Phase B dispersed in Phase A; C’. The unstable emulsion progressively separates; D’. The (purple) surfactant positions itself on the interfaces between Phase A and Phase B, stabilizing the emulsion An emulsion is a thermodynamically unstable system consisting of at least two immiscible liquid phases, one of which is dispersed as globules in the other liquid phase, stabilized by the presence of an emulsifying agent.
- 6. Theory of emulsification Change from A to B will significantly increase of the surface area of phase. e.g., if 1 cm 3 of mineral oil is dispersed into globules having diameter of 0.01 m in 1 cm 3 of water, how much will be the surface area increased. The surface area will become 600 m 2 (greater than a basketball court); the surface free energy will increase by 8 calories. Therefore, emulsions are thermodynamically unstable, and the droplets have the tendency to coalesce . Emulsifying agents are needed to decrease the surface tension and to stabilize the droplets.
- 8. 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.
- 13. Auxiliary emulsifying agents Auxiliary (secondary) emulsifying agents include those compounds that are normally incapable themselves of forming stable emulsion. Their main values lies in their ability to function as thickening agents and thereby help stabilize the emulsion.
- 29. Preparation of nanoparticles from microemulsion precursors
- 30. THANK YOU,,,,,,,
Editor's Notes
- Butter, margrine, salad dressings. Why it is thermodynamically unstable: creating small droplets will create large surface area. Since the surface has the tendency to decrease due to surface tension, emulsions are unstable. Internal vs. external; dispersed vs. continuous phase.
- Oil dose not mean that it has to be the conventional oil. Any liquid that is not miscible with water will be just OK. Double emulsion is rarely used. It might be good to increase the stability of a certain chemical. However, the chemical has to diffuse through several layers to be released, making the drug not biologically available.
- Emulsifying agents can prevent coalescence or at least reduce its rate to negligible. It will form a film around the dispersed globules. The strength of an emulsifying agent lies in its ability to form a firm film.
- This explains why a surfactant with a HLB value of 8-16 helps the formation of o/w emulsion, whereas one with an HLB value of 3-8 aids the formation of w/o emulsion.
- It is necessary to have a predominantly hydrophilic emulsifier in the aqueous phase and a hydrophobic agent in the oil phase to form a complex film at the interface. SCS – chol lead to a complex film, and thus excellent emulsion. Oleyl alcohol does not pack well. So the emulsion is unstable.
- Acacia is a carbohydrate gum soluble in water and form O/W emulsions. Emulsion prepared with acacia is stable over a wide range of pH. Gelatin is a protein. It has been used for many years as an emulsifying agent. Type A: derived from acid treated precursors, having a IE of 7-9. it acts best at pH 3. Type B: IE = 5, best at pH 8. This affects the stability a lot. Lecithin is natural, from eggs or plants. A mixture of lipids, mainly PC, PI, PE, PS, and phsophatidic acid. Choleseterol is a major component of wool alcohols. It is cholesterol that gives wool fat its capacity to absorb water and form a w/o emulsion.
- Reversible. Need to be shaken well prior to use. It does not look good. Also, if not uniformally distributed, required amount of the active ingradient might not be achieved.
- Changing from a soft soap into a hard soap, a hydrophilic surfactant into lipophilic surfactant.
- Bacteria have been shown to degrade non-ionic and anionic surfactants, glycerin, and vegetable gums. This will damage the emulsion.
- In situ soap method is also called nascent soap methods. Nascent means beginning to exist or to develop. The emulsifier is formed as the emulsions are made.
- Cod liver oil , as its name suggests, is an oil extracted from cod livers . It is a nutritional supplement , in the past commonly given to children . Cod liver oil is one of the most effective providers of omega-3 fatty acids and is widely taken to ease the pain and joint stiffness associated with arthritis but has also been clinically proven to have a positive effect on heart, bone and brain health, as well as helping to nourish skin, hair and nails. [ citation needed ] As well as being an excellent source of vitamin A and vitamin D , it is also a good source of omega-3 fatty acids ( EPA and DHA ). Depending on the quality of the oil, the flavor and aroma range from a mild sardine -like flavor, to an intense and obnoxious odor of rotten fish and rancid oil. High quality cod liver oil is "a pale-yellow, thin, oily liquid, having a peculiar, slightly fishy, but not rancid odor, and a bland, slightly fishy taste." It has recently become popular to flavor cod liver oil with citrus or mint essence to make it more palatable. People who grew up in Asia often have terrible childhood memories of being force-fed Scott's Emulsion (a popular brand of cod liver oil supplement) until the orange-flavoured version was released. Cod liver oil is made by cooking cod livers with steam and then pressing/decanting the cooked livers to extract the oil. By contrast, fish oils are extracted from the cooked whole body tissues of fatty fish during the manufacture of fish meal . Cod liver oil and fish oil are similar but have a somewhat different composition: fish oil has a much lower content of vitamins A and D compared to liver oils. This may pose a problem in that one may need to exceed the Recommended Dietary Allowance (RDA) of vitamins A and D in order to obtain therapeutic amounts of EPA and DHA from cod liver oil. These vitamins are fat soluble, so it's possible for dietary excess (well above the RDA) to accumalate and become harmful. Because the body naturally produces vitamin D when exposed to sunlight , a common way to benefit from both oils while avoiding a vitamin D overdose is to take cod liver oil during late fall through winter , and fish oil during spring through summer . The ideal dosage and timing of consumption depends on your seasonal sun exposure (and therefore natural vitamin D production). The only way to be certain of any possible vitamin D deficiencies or overdosing (from supplements) is to have your levels checked. On the other hand, the RDA of vitamin D is considered by many to be strongly understated. Most adults don't even meet the RDA. In 2005 researchers at the University of California reported that Vitamin D can dramatically lower the risk of developing different types of cancers, cutting in half the chances of getting breast, ovarian, or colon cancer Triturate (Tricherat): To rub, crush, grind, or pound into fine particles or a powder; pulverize.
- Mucilage: A sticky substance used as an adhesive.
- Oleaginous materials in o/w emulsion: a, occasionally, a small amount of oily material is added if sufficient emulsifier was used in the original formation B, a small amount of oil-soluble drug can be added if it is dissolved in a very small quantity of oil. Potentional drug solvent interaction should be avoided.
- Unique emulsion or swelled micelles. Thermodynamically stable--- formed spontaneously. Surfactants and co-surfactants make the surface tension to zero. Transparent is due to its smaller size, which cannot reflex visible light.
- glyceryl oleate+polyoxyl 40 fatty acid derivatives (surfactants)/tetraglycol (co-surfactant)/isopropyl palmitate/water by constructing pseudo-ternary phase diagrams at fixed co-surfactant/surfactants (CoS/S) ratios