Oral Dosage Forms Solutions, Suspensions and Emulsions

2 Oral Dosage Forms Solutions, Suspensions, and Emulsions 

Besides suspensions, emulsions are dosage forms which have considerable traditional use in pharmacy. The technology of emulsions [oil-in-water (o/w) or water-in-oil (w/o)] is clearly established. In recent years, various emulsions such as water-oil in water have been developed, where water droplets are dispersed in oil droplets which are in turn dispersed in water. Such multiple emulsions may be used for prolonged oral action or intramuscular depot therapy. 

Because of their large interfacial area, emulsions are basically unstable. In order to produce a stable emulsion, a surfactant is mostly needed. The surfactants are adsorbed at the oil-water interface, forming a link between the two phases of different polarity. For this purpose, a wide variety of emulsifying agents is currently available. Polysaccharides such as arabic gum, tragacanth, Karaya gum, and different seaweed carbohydrate polymers have been employed. They, however, show considerable batch-to-batch variations and might support microbial growth. 

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