Determination of SU5416, a novel angiogenesis inhibitor, in human plasma by liquid chromatography

A high-performance liquid chromatographic (HPLC) assay with UV detection has been developed for the quantitative determination of the antiangiogenic agent SU5416 in human plasma. Sample pretreatment involved a single protein-precipitation step with acetonitrile containing the internal standard, chrysin. Separation of the compounds of interest was achieved on a column packed with HP Zorbax C₈ material (5 μm particle size; length: 150 mm; i.d.: 4.6 mm) using a dual solvent system of 0.01 M aqueous ammonium acetate and acetonitrile delivered as a nonlinear gradient at a flow-rate of 1.00 ml/min. Simultaneous UV detection was performed at 440 nm (SU5416) and 268 nm (chrysin). The calibration graph was fit to log-transformed response-concentration data over a range of 10-5000 ng/ml. Values for accuracy and precision, obtained from six quality controls analyzed on different days in replicates of 3 or 6, ranged 92.9-109 and 0.8-6.2%, respectively. The developed method was successfully applied to study the pharmacokinetics of SU5416 in a cancer patient receiving the drug as a 1 h infusion.