Stability of Cabazitaxel Solution after Dilution in Normal Saline and Stored in Glass

Objective: To evaluate the stability of cabazitaxel diluted in 0.9% sodium chloride (NS) and stored in glass. Methods: A reverse-phase stability-indicating liquid chromatographic method was developed and validated before the study. The commercially available product was prepared according to the manufacturer’s instructions, and further diluted in NS to obtain concentrations of 0.120 mg/mL and 0.240 mg/mL cabazitaxel and stored in glass under refrigeration and at 25ºC, all of them protected from light. The concentration of cabazitaxel was evaluated over a period of 21 days. Results: Physical stability: The visual inspection of the stored samples to 25ºC (0.120 mg/mL and 0.240 mg/mL) indicated appearance of a white precipitate in both cases on the day 2 of study. In the case of the refrigerated samples, a similar precipitate appears on the day 6 of the study for the 0.240 mg/mL concentration and on the day 21 for 0.120 mg/mL concentration. Chemical stability: The samples that stay physically stable have been evaluated by HPLC method obtaining in all determinations a remaining percentage >95%. Solutions of cabazitaxel were subjected to a forced degradation analysis. Conclusion: Solutions of cabazitaxel 0.120 mg/mL prepared in NS and stored in glass retained more than 95% of the initial drug concentration when stored for one day at 25ºC and for twenty days at 4ºC. Solutions of cabazitaxel 0.240 mg/mL prepared in the same conditions retained more than 95% of the initial drug concentration when stored for one day at 25ºC and for two days at 4ºC.