Cephalothin Stability in Normal Saline, Five Percent Dextrose in Water, and Dianeal® Solutions

Abstract

ABSTRACT
The stability of cephalothin sodium (1 g) in polyvinyl chloride minibags containing 50 mL of 0.9% normal saline, 5% dextrose in water (D5W) or 500 mg in 2L of Dianeal® (containing 1.5% or 4.5% dextrose) was evaluated using a validated, stability-indicating, liquid chromatographic method during 30 days storage at 4° C and room temperature (23°C). Physical inspections and pH determinations also completed on each of the 11 study days during the 30 day storage period.

During the 30-day study period all solutions lost more than 10% of the initial cephalothin concentration. In D5W and saline solutions stored at 4°C, 10% of the initial concentration was lost within 17 days, and at room temperature 10% was lost within one day. In Dianeal®, regardless of the dextrose concentration, solutions stored at 4°C, lost 10% of the initial concentration within eight days, and at room temperature 10% was lost within one day. During the 30-day study period the pH decreased in every solution. However, the decrease was less than 1.0 of a pH unit. The colour of solutions stored at room temperature gradually changed during the study period, becoming a deeper yellow. Solutions stored at °C remained clear and colourless throughout the study period.

We conclude that cephalothin solutions (1 g/50 mL of D5W or normal saline) stored at 4°C for seven days followed by 12 hours storage at room temperature will retain 90% of the initial cephalothin concentration, whereas, cephalothin concentrations stored in Dianeal® (500 mg/2L) at 4°C will lose approximately 8% of the initial concentration after only three days storage at 4°C followed by an additional 12 hours storage at room temperature.