If a CSP has a Beyond Use Date (BUD) of less than or equal to 12 hours at controlled room temperature, which category does it belong to?

The correct classification for a compounded sterile preparation (CSP) that has a Beyond Use Date (BUD) of less than or equal to 12 hours at controlled room temperature is indeed Category 1. This category typically includes CSPs that are prepared under conditions that provide a shorter time frame for their use due to concerns about sterility and stability.

In this category, the emphasis is placed on the immediate use of the CSP, which is why the BUD is limited to 12 hours or less. This is particularly relevant in emergency situations or when the preparation can be used soon after compounding, thus minimizing the time the preparation spends outside of controlled conditions where sterility is maintained.

The other categories involve different time frames and conditions for BUDs. For example, Category 2 includes preparations that can have a longer BUD, that generally involves more complex compounding processes or where multiple preparations are made, hence the handling and storage conditions differ significantly from those in Category 1. Categories 3 and 4 are even more extensive and involve either extended BUDs under various storage conditions or non-sterile to sterile preparations, which are not applicable for a CSP with a BUD of only 12 hours.

Therefore, understanding the limitations