![]() They are preferred for topical preparations such as creams They are preferred for oral formulations as the taste of oils can be masked. Oil-soluble drugs are more quickly released from W/O emulsions Water-soluble drugs are more quickly released from O/W emulsions. They are used externally to prevent evaporation of moisture from the surface of the skin, for example, cold cream They are used externally to provide a cooling effect, for example, vanishing cream. They are greasy and not easily washed by water. They are nongreasy and easily washed from the skin surface. Water is the dispersed phase and oil is the dispersion medium. Oil is the dispersed phase and water is the dispersion medium ![]() Emulsions are physically unstable and the Vario. However, they mayĪlso be administered intravenously, rectally, or orally. The major use of emulsions is as cream formulations (for external application). The differences between O/W and W/O emulsions are provided In general, all oral emulsions tend to be oil-in-water as the oily phase is usually less pleasant to take and more difficult to flavor. Water in oil (W/O) emulsions: The internal phase is composed of water droplets and the external phase is nonaqueous. Oil is the dispersed phase and water is the dispersion medium.Ģ. Oil in water (O/W) emulsions: The oil (internal or dispersed) phase is dispersed as droplets throughout the aqueous phase (external or continuous phase or dispersion medium). Examples are liquid paraff in emulsion, cod liver oil emulsion.ġ. Emulsions enhance the rate and extent of absorption through the alimentary canal, improve the solubility of poorly water-soluble drugs, and can prolong drug action. It also improves penetration and spreadability. It improves the taste of objectionable medicinal agents and makes them more acceptable. Emulsion increases the stability of many drugs that are unstable in an aqueous solution. The liquid droplets are generally known as the dispersed phase or internal phase, whereas the liquid in which they are dispersed is known as the continuous phase, dispersion medium, or external phase. The stability of the emulsion is increased by adding another substance known as the emulsifying agent or emulsifiers. Such a system possesses minimal stability because the droplets quickly coalesce and the two liquids get separated. The following are the disadvantages of using emulsions as dosage forms:Įmulsion is a heterogeneous system consisting of one immiscible liquid dispersed in another in the form of droplets whose diameter, in general, exceeds 0.1 microns.Advantages and Disadvantages of emulsions as Dosage forms.
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