The determination of allopurinol and oxipurinol in human plasma and urine.

A method is described for allopurinol and oxipurinol assay within human plasma and urine in the range expected during therapy. The method is based on high-performance ion-exchange chromatography following an efficient sample purification step using Chelex-100 resin in the Cu2+-form. Linear calibration curves are produced for allopurinol over the range 0.05-10 mumole/1 (0.068-1.36 mug/ml) in plasma and 0.005-1 mmole/1 (0.68-136 mug/ml) in urine and for oxipurinol 0.5-100 mumole/1 (0.076-15.2 mug/ml) in plasma and 0.1-2 mmole/1 (15.2-304 mug/ml) in urine.