Stability and sterility of cimetidine admixtures frozen in minibags

The stability and sterility of cimetidine hydrochloride admixtures after freezing for extended periods were investigated. Cimetidine hydrochloride, 300 mg, was added to each of six 50-ml minibags containing 5% dextrose injection. The cimetidine concentration was determined and the bags were frozen for up to 30 days. After freezing for the appropriate length of time, the bags were thawed. Cimetidine concentrations were determined by high-pressure liquid chromatography immediately and then daily for eight days while the admixtures were refrigerated. Sterility tests were carried out throughout the study. Data were analyzed by least-squares linear regression to test for trends. The cimetidine hydrochloride admixtures were stable while frozen for up to 30 days and for at least eight days following thawing when kept under refrigeration. Sterility of the admixture was maintained throughout the study period.