In drug formulation, which type of emulsion is preferred for lotions?

In drug formulation, oil-in-water emulsions are preferred for lotions primarily because they provide a lighter, more fluid texture that is ideal for topical application. This type of emulsion allows for quick absorption into the skin, making it suitable for providing hydration without the greasy feel associated with thicker formulations.

Oil-in-water emulsions contain a higher proportion of water relative to oil, which enhances the moisturizing effects while making the product easier to spread and apply. This is particularly advantageous for lotions that are intended for daily use, as consumers typically seek products that are effective yet comfortable to apply on large areas of the skin.

In contrast, other formulations like water-in-oil emulsions tend to be thicker and greasier, which may not be as desirable for a lotion intended for broader application. Thick creams and aqueous solutions also do not provide the same emollient and hydrating benefits that users expect from lotions. Thus, the oil-in-water emulsion strikes the right balance between efficacy and user experience.