In selecting the ointment base, which factor is NOT typically considered?

• A. Desired release rate of the substance from the ointment base.
• B. Desirability of topical or percutaneous drug absorption
• C. Solubility of the drug in the base
• D. Characteristics of the surface to which it is applied.

Answer: (C)

When choosing an ointment base, the focus is on how the base will control the drug’s delivery to the skin and how it fits the application site. The most important considerations are the desired release rate of the active substance from the base, how favorable the base is for topical or percutaneous absorption, and the characteristics of the surface where it will be applied (such as skin condition, moisture, and the area involved). These factors together determine how much and how quickly the drug will reach and penetrate the skin, balancing efficacy with patient comfort and practicality.

The solubility of the drug in the base is not typically the primary criterion. Even if a drug is highly soluble in the base, you can tailor release and absorption through the choice of base type and formulation strategy to achieve the desired therapeutic effect.