Which type of ointment base allows for absorption of water?

Absorption bases are specifically designed to allow for the absorption of water. They typically contain emulsifying agents that facilitate the incorporation of water into the oil phase, which makes them unique in their ability to retain moisture. This quality allows them to be used effectively for topical applications that benefit from both occlusiveness (characteristic of oily formulations) and hydration (the presence of water).

In contrast, oleaginous bases are primarily composed of oils and do not have the capacity to absorb water, which limits their hydrophilic potential. Water-in-oil emulsions tend to have a greater oil phase and thus do not allow for significant water absorption, while oil-in-water emulsions have a predominant water content and typically do not absorb additional water effectively in the same manner as absorption bases do. This distinction is key to understanding the functionality of different ointment bases in pharmaceutical formulations.