What is the primary method of reducing particle size in compounding ointments?

The primary method of reducing particle size in compounding ointments is trituration. Trituration involves the process of grinding solid materials into finer particles using a mortar and pestle. This technique allows for the reduction of particle size, which is critical in achieving a uniform distribution of the active ingredients within an ointment base. A finer particle size enhances the absorption of the active ingredients and improves the overall stability and consistency of the ointment.

Levigation is also a method used to reduce particle size but specifically involves mixing the solid with a liquid (often a small amount of an inert liquid) to create a paste, which is then ground to further reduce particle size. This method is often used to create smooth compositions, but trituration is the more general and widely applicable method for size reduction in compounding.

Geometric dilution is a technique used to ensure uniform mixing of two powders of different quantities in a compounding process, rather than directly reducing particle size. Mixing refers to combining ingredients but does not specifically address the reduction of particle size.

Therefore, trituration is the primary and most effective method for reducing particle size in the context of compounding ointments.