Anticipatory compounding, or preparing compounded medications before the actual receipt of a prescription or practitioner’s order, is an important component of pharmacy practice. It allows compounding pharmacies with a history of filling certain prescriptions to make up a larger batch and to make sure that medications will be ready when they are needed. It reduces the cost of compounded medications as economies of scale can be realized with larger batches and less waste of chemicals, dilutions, fillers, and other associated products. It also leads to more accuracy and uniformity in the finished medications as larger batches decrease the variation that will always exist from preparing multiple, smaller batches.
Compounding in anticipation is even more important in the preparation of sterile medications (i.e., injectibles and eye drops). Because a guarantee of sterility is essential, sterile compounds should be prepared far enough in advance to allow for the receipt of results from testing that is often mandated by regulatory authorities. For example, USP Chapter <797> for sterile compounding requires testing for sterility and endotoxins if a batch size consists of 25 or more units. For many of these sterile medications, test results can take up to 14 days to complete. So quality and safety is greatly enhanced if sterile compounding is completed far enough in advance so that the finished medications can be tested without delaying their availability to patients and practitioners who often have medical needs that are time sensitive.
Anticipatory compounding is only used for those medications that are in sufficient demand to justify their compounding prior to receipt of a prescription. If a unique or unexpected prescription is received by a pharmacy, it is compounded “on-demand” and a patient or practitioner may have to wait to receive the required medication. But it is common for many expected orders to have the same formula, and these can be compounded in advance to benefit both the patient and the pharmacy.