Physical and chemical stability of cisplatin infusions in PVC containers

Study objectives: To determine the extended chemical and physical stability of cisplatin infusions in PVC containers at normal in-use concentrations in saline, with and without added electrolyte combinations relevant to clinical practice. Methods: Cisplatin infusions 0.1-0.4 mg/mL were prepared in normal saline, with and without magnesium sulphate and potassium chloride supplements in 500 mL PVC bags, and stored at 25°C protected from light. Chemical stability was assessed by a stability-indicating LC method. Evidence for precipitation was detected by a light-blocking particle count method for sub-visible particles, supported by visual examination. pH and weight changes were also monitored for at least 28 days. Results: Both 0.1 mg/mL and 0.4 mg/mL infusions, with or without the added electrolyte supplements, were chemically stable over 28 days at 25°C. The pH of infusions varied by no more than 0.2 units over this time, there was no visible precipitation, and no significant changes in sub-visual particulate levels or infusion weight. The study was restricted to 28 days because small, visual precipitation was evident in some infusions after 25 days. Conclusion: Cisplatin infusions at concentrations ranging from 0.1-0.4 mg/mL, in 500 mL PVC bags containing either 0.9% sodium chloride or 0.9% sodium chloride + 20 mmoL KCI + 8 mmoL MgSO₄ were physically and chemically stable for up to 28 days at 25°C, when protected from light. Extending shelf lives beyond this period is unsafe due to the potential development of precipitates.