Excipients play a crucial role in pharmaceutical formulations, going beyond being mere "inert diluents." They are essential components used to overcome the limitations posed by active drugs and address challenges related to drug properties.

One of the key functions of excipients is to enhance the bioavailability of poorly water-soluble active pharmaceutical ingredients (APIs). By incorporating specific excipients into formulations, they can improve solubility, dissolution rates, and ultimately increase the absorption and effectiveness of these APIs within the body.

However, excipients are not limited to just enhancing bioavailability. They also have the capability to reduce bioavailability when necessary. This can be useful in cases where controlled release or targeted drug delivery is desired. Excipients can be employed to slow down or modify drug release profiles, ensuring optimal therapeutic outcomes.