Compatibility and stability of paclitaxel combined with cisplatin and with carboplatin in infusion solutions

OBJECTIVE: To evaluate the physical compatibility and chemical stability of paclitaxel at concentrations of 0.3 and 1.2 mg/mL with cisplatin 0.2 mg/mL in NaCl 0.9% injection and with carboplatin 2 mg/mL in NaCl 0.9% injection and dextrose 5% injection over 7 days at 4, 23, and 32 °C. DESIGN: The test samples were prepared in polyolefin bags of the infusion solutions at the required drug concentrations. Evaluations were performed initially and after 4 hours, and 1, 3, 5, and 7 days of storage at temperatures of 4, 23, and 32 °C for physical and chemical stability. Physical stability was assessed by using visual observation in normal light and using a high-intensity monodirectional light beam. In addition, turbidity and particle content were measured electronically. Chemical stability of the three drugs was evaluated by using three stability-indicating HPLC analytical techniques. RESULTS: All samples were physically stable through 1 day. However, microcrystalline precipitation of paclitaxel occurred in 3 days in some samples and within 5 days in all samples. Paclitaxel concentrations remained above 90% in all samples throughout the study. Cisplatin admixtures exhibited paclitaxel concentration-dependent decomposition with cisplatin losses of approximately 5-8% in 4 hours and approximately 20% in 1 day at 23 and 32 °C in the paclitaxel 1.2 mg/mL admixtures. With paclitaxel 0.3 mg/mL in the admixtures, cisplatin losses were about 10% in 7 days at these temperatures. Carboplatin in admixtures with both concentrations of paclitaxel was stable for 7 days at 4 °C, but sustained losses of about 10% and 12% in 3 days at 23 and 32 °C, respectively. CONCLUSIONS: Admixtures of paclitaxel 0.3 and 1.2 mg/mL with cisplatin and carboplatin are limited in their utility time by both paclitaxel microcrystalline precipitation and decomposition of cisplatin and carboplatin. The admixture of paclitaxel 1.2 mg/mL with cisplatin 0.2 mg/mL in NaCl 0.9% injection exhibits unacceptable loss in 24 hours. All other combinations were physically and chemically stable for at least 24 hours at 4, 23, and 32 °C.