Basics of sterile compounding: compounding by weight versus compounding by volume.

In compounding small volumes of sterile preparations, it is generally acceptable to use volumetric measurements. However, when compounding larger volumes or when the sterile preparation has a low concentration, it is best to compound by weight for greater accuracy. This article provides the procedures that can be followed when compounding by weight as compared to volume and provides an example of the steps involved in compounding 18.5 liters of progesterone 100 mg/mL injection.