Light-induced deterioration test of carboplatin under clinical settings

Chemotherapeutic drug dosages are calculated precisely based on the patient's height, body weight, and renal function, etc. To ensure safe and favorable outcomes of treatment, dosing solutions are prepared by appropriate mixing of the drug solutions based on such calculations. The package inserts for many injectable preparations include a warning for storing the product "shielded from light." However, there are no reports of stability assessment of a mixed product against light exposure or the residual amount of active ingredient in the dosing solution during or at the end of treatment. We evaluated the stability of carboplatin from the time of mixing of the dosing solution until the end of drug infusion in a clinical-like setting. With 4-hour exposure to outdoor scattered light, the dosing solution began to show discoloration by 1 hour, becoming dark yellow by 4 hours, with reduction of the percent residual carboplatin to about 23%. To identify the optimal light-shielding shade, the dosing solution was shielded from outdoor scattered light with 1 of 3 protective covers: aluminum foil, yellow plastic shade, and brown plastic shade. The yellow plastic shade prevented any changes of the appearance of the dosing solution during the 4-hour exposure period. The percent residual carboplatin, determined by HPLC, in the dosing solution shielded with a yellow plastic shade was about 85.2% at 2 hours and 78.6% at 4 hours. Thus carboplatin dosing solution should be completely shielded from light until infusion is completed.