Background: The actual volume that can be recovered from a drug vial (the ‘yield’) often differs to the nominal volume. This can potentially complicate vial selection as well as reconciliation of remaining volumes.
Aim: To investigate factors which may influence the yield from a range of drug vials commonly used in compounding parenteral oncology drugs (including supplied overage, type of device used to access the vial, user technique, and the number and size of syringes used), and to develop a guide for pharmacists performing product inspection to reference when reconciling remaining drug volumes.
Method: Volumes withdrawn from a range of drug vials were measured and recorded during live production. The yield, user, access device and the size and number of syringes used were recorded.
Results: Of the 45 vial types measured (where n≥5), 5 yielded within ±0.1mL of the nominal volume, 5 yielded more than 0.1mL less than the nominal volume, and 35 yielded more than 0.1mL above the nominal volume. All vials that yielded less than the nominal volume were drugs that are supplied in powder form. All solution vials yielded at least the nominal volume. There was no correlation between vial yield and the number or size of syringes used, nor consistent variation between participating users. When a spike (ICU Medical, CH-80) was used to access the vial instead of a needle (BD, 19G), the difference in yield was negligible.
Conclusions: Knowledge of expected vial yield allows Pharmacists to optimize vial usage and conduct accurate reconciliation of remaining volumes. Supplied overage is the most significant factor influencing vial yield positively, while drugs supplied in powder form often yielded less than the nominal volume. Facilities should develop their own guidelines specifying minimum and maximum drug vial yields to account for local differences between user technique and drug/spike brands.