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

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 degrees C.

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 degrees 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.

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 degrees 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 degrees C, but sustained losses of about 10% and 12% in 3 days at 23 and 32 degrees C, respectively.

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 cisplatin loss in 24 hours. All other combinations were physically and chemically stable for at least 24 hours at 4, 23, and 32 degrees C.