Stability of cisplatin and etoposide in intravenous admixtures

The stability of various concentrations of etoposide and cisplatin in intravenous admixtures under various storage conditions was studied. Admixtures containing etoposide (200 and 400 micrograms/mL) with cisplatin (200 micrograms/mL) were prepared in 0.9% sodium chloride injection and in 5% dextrose and 0.45% sodium chloride injection. The admixtures were stored in either polyvinyl chloride bags or glass bottles. Mannitol and potassium chloride were added to selected admixtures. Half of the admixtures were protected from light, while the other half were exposed to fluorescent light. All admixtures were stored at room temperature. Samples were visually inspected and assayed for etoposide and cisplatin content by high-performance liquid chromatography within 15 minutes after admixture preparation and after 8, 24, and 48 hours of storage. Etoposide and cisplatin concentrations decreased less than 10% from the initial concentration after eight hours of storage. At 24 hours, the admixtures containing etoposide 400 micrograms/mL and cisplatin 200 micrograms/mL (with additives) in 0.9% sodium chloride injection precipitated. The decrease in etoposide concentrations during the first 24 hours in the rest of the admixtures was less than 10% of the initial concentration. The change in etoposide concentration was related to the type of i.v. solution and the presence of additives. After 24 hours, the change in cisplatin concentrations was less than 10% of the initial concentration, except in the admixtures that precipitated. For cisplatin, the presence of light was related to an increased loss of cisplatin concentration.(ABSTRACT TRUNCATED AT 250 WORDS)