What is the purpose of using a 0.22 micron filter in CSP sterilization?

The purpose of using a 0.22 micron filter in compounded sterile preparations is primarily to filter out microorganisms. Filters sized at 0.22 microns are effective at removing bacteria and other particulate contaminants from solutions, ensuring that the final product is free of viable microorganisms. This is crucial in maintaining sterility in compounded sterile preparations, particularly when preparing injectables or intravenous solutions, as the presence of microbes can lead to serious infections and complications for patients.

The other options address different concepts not directly related to the primary function of a 0.22 micron filter. For instance, while removing pyrogens is an essential part of ensuring product safety, it typically requires different processes rather than filtration through a 0.22 micron filter. Ensuring a proper pH balance is important for the stability and efficacy of a compounded preparation but is not related to the filtering process. Preventing chemical reactions is also a significant consideration in compounding, but it is not a function of the physical filtration process provided by a 0.22 micron filter. Therefore, the correct role of the filter is specifically to ensure that microorganisms are effectively removed, allowing for a sterile final product.