Analysis of Allopurinol and Oxipurinol in Plasma by Reversed Phase HPLC

Abstract A reversed phase HPLC assay is described for the quantitation of allopurinol and oxipurinol in human plasma. The strategies for the development of this method are discussed. The analysis is performed on a C-18 column using an acidic aqueous mobile phase. Sample preparation consists of protein precipitation with a mixture of trichloracetic acid and perchloric acid. The detection limit of the assay for both substances is in the region of 30ng/ml. This method has been applied to an investigation of the relative bioavailability of two commercial preparations of 300mg allopurinol tablets in eight healthy volunteers.