Lanolin is an example of which emulsion type?

Lanolin is an example of which emulsion type?

• A. O/W emulsion
• B. W/O emulsion
• C. Water-soluble base
• D. Gel

Answer: (B)

Lanolin is a lipid-rich, waxy substance that is not soluble in water. In topical formulations, this type of oily material forms emulsions with water droplets dispersed within it, meaning water-in-oil is the system. The oil is the continuous phase and the dispersed phase is water, which gives an occlusive, emollient feel typical of W/O emulsions used in ointments. In contrast, an oil-in-water system would have oil droplets dispersed in water and would be less occlusive and more readily washed off. So lanolin exemplifies a water-in-oil emulsion.

Lanolin is a lipid-rich, waxy substance that is not soluble in water. In topical formulations, this type of oily material forms emulsions with water droplets dispersed within it, meaning water-in-oil is the system. The oil is the continuous phase and the dispersed phase is water, which gives an occlusive, emollient feel typical of W/O emulsions used in ointments. In contrast, an oil-in-water system would have oil droplets dispersed in water and would be less occlusive and more readily washed off. So lanolin exemplifies a water-in-oil emulsion.