PLASMA MITOMYCIN-C CONCENTRATIONS DETERMINED BY HPLC COUPLED TO SOLID-PHASE EXTRACTION

The aim of this study was to set up a method for quantification of pla sma mitomycin C (MMC) concentrations during intravesical chemotherapy delivered in the presence of local bladder hyperthermia (HT). In compa rison with existing methods, this assay, characterized by relative sim plicity and efficiency, resulted in the facilitation of performance wi th nondedicated instrumentation or nonspecialized staff. Purification from plasma matrix was carried out by solid-phase extraction under vac uum. The purified drug was then collected directly into the vials of t he HPLC autosampler. Chromatographic analysis was performed on a rever sed-phase C-18' column with water:acetonitrile (85:15 by vol) as the m obile phase and the UV detector set at 365 nm. The use of porfiromycin as internal standard provided a method with good within-day precision (CV 6.0% at 5 mu g/L, n = 6), linearity (0.5-50 mu g/L), and specific ity. The lower limit of detection (less than or equal to 0.5 mu g/L) p roved to be suitable for plasma pharmacokinetics monitoring in two tes ted patients treated with MMC+HT for superficial bladder cancer.