Question

Which of the following ointment bases is an “absorption base”?

• A. Hydrophilic petrolatum USP.
• B. Hydrophilic ointment USP
• C. PEG ointment NF
• D. Yellow ointment, USP

Answer 1

The Correct Option is A

To solve the given question about ointment bases, we need to understand the classification of ointment bases in pharmacology. There are primarily four types of ointment bases:

1. Hydrocarbon bases: These are oily bases that are water-repellent and include substances like white petroleum jelly.
2. Absorption bases: These are anhydrous but can absorb water, leading to water-in-oil emulsions. They enhance the absorption of water and other therapeutic agents. Hydrophilic petrolatum USP belongs to this category.
3. Water-removable bases: These are oil-in-water emulsions that can be washed off more easily and include products such as hydrophilic ointment USP.
4. Water-soluble bases: These are usually greaseless, and an example includes PEG ointment NF.

With this classification in mind, let's match the options with the correct categories:

• Hydrophilic petrolatum USP: This is an absorption base, as it can absorb water and form emulsions.
• Hydrophilic ointment USP: This is a water-removable base, not an absorption base.
• PEG ointment NF: This is a water-soluble base, typically greaseless and absorbing no or minimal water compared to absorption bases.
• Yellow ointment, USP: Generally considered a hydrocarbon base, similar to petrolatum.

Based on the explanation above, the correct answer is Hydrophilic petrolatum USP, as it is the only option classified as an absorption base, capable of absorbing water and forming emulsions.