Extemporaneously prepared formulations of cefazolin are unstable at room temperature and should be stored in a refrigerator.

This study demonstrated that the concentrating effect due to evaporation under the storage conditions described, over 16 days, was not of significance and the product was stable.

All preparations were found to be physically and chemically stable for at least 48h, as concentration changes were within 10% of their initial level, with no development of haze, precipitate or colour. Light appeared to have a negligible effect. Although pH changes were observed, they were inconsistent and were within the ranges in which the drugs are expected to remain stable. Pethidine and metoclopramide admixtures can, therefore, on stability grounds be used for the concomitant management of pain, nausea and vomiting.