What is a common example of a soluble diluent used in compounding?

Mannitol is a common example of a soluble diluent used in compounding because it is readily soluble in water, making it suitable for various pharmaceutical formulations. Soluble diluents are often utilized to help improve the flow properties of powders, enhance the dissolution of the active ingredient, and ensure proper dosage when preparing oral or parenteral medications.

Mannitol not only functions as a diluent due to its solubility but also contributes a sweet flavor and can provide osmotic properties that are beneficial in certain formulations, particularly for solutions used in intravenous therapy. Its inert characteristics and low-calorie profile further support its use in compounding practices.

While the other substances mentioned—calcium phosphate, cellulose, and starch—have their own roles in compounding, they are typically used for different purposes. Calcium phosphate is often used for its buffering properties, cellulose is primarily used as a thickening or binding agent, and starch is commonly utilized as a disintegrant or binder in tablet formulations. However, none of these demonstrate the same level of solubility in water as mannitol.