Abstract
► The studies describe a validated and sensitive HPLC assay for R-(−)-gossypol pharmacokinetic evaluation of gossypol. ► A simple acetonitrile deproteinization method was applied for plasma sample preparation with satisfying recovery. ► A Schiff's base derivative, R-(−)-gossypol-diamino-propanol was synthesized and used as internal standard.
R-(−)-gossypol acetic acid (AT-101), a natural BH3 mimetic, is investigated in a Phase I/II clinical trial for the treatment of advanced solid tumor malignancies. Gossypol undergoes rapid degradation in solution phase, which causes major technical difficulty for its quantitation in plasma. We developed and validated a sensitive HPLC assay for pharmacokinetic evaluation of gossypol. Acetonitrile deproteinization method was chosen for sample preparation and Schiff's base derivative, R-(−)-gossypol-diamino-propanol (GDP), was used as internal standard. Chromatographic separation of gossypol in plasma was performed using a Zorbax Eclipse XDB column C18 at 30°C. The mobile phase consists of 10mmol/L KH2PO4 (pH 3.0) and acetonitrile (20:80) at 1.0mL/min flow rate. Linearity ranged over 56–3585ng/mL (R2=0.9997±0.0003, n=4), and the limit of detection was 28ng/mL. The intra- and inter-assay precision was less than 13.7% and the bias ranged from −7.4 to 7.0%. The method was successfully applied to characterize the pharmacokinetics of AT-101 in a Phase I clinical trial. The validated assay is accurate, and sensitive with minimum loss and rapid analysis time and suitable for quantification of gossypol for pharmacokinetics evaluation.