Which method of sterility testing is favored to extend beyond-use dates (BUD)?

The method favored to extend beyond-use dates (BUD) is Terminal Filtration by Membrane Filtration. This technique is utilized because it effectively removes microorganisms from the final product, ensuring that the compounded sterile preparation remains free from contamination. By filtering the solution through a membrane with a specific pore size, typically 0.2 micrometers, any viable bacteria or fungi are retained, thereby enhancing the overall sterility of the product.

Using this method allows for a higher level of assurance regarding the sterility of the compounded preparation, which is crucial when determining appropriate BUDs. Extended BUDs require confirmed sterility, and terminal filtration provides that assurance by minimizing the risk of microbial contamination effectively.

Other methods, while useful for various purposes, do not provide the same level of assurance for extending BUDs. For instance, direct inoculation and microbial culture testing may not capture all possible contaminants effectively if performed post-compounding, while visual inspection alone only identifies visible particulates and defects without addressing microbial contamination. Each method has its purpose, but terminal filtration is specifically designed for maintaining sterility over an extended period.