Simultaneous determination of a new anticancer agent (NB-506) and its active metabolite in human plasma and urine by high-performance liquid chromatography with ultraviolet detection.

A high-performance liquid chromatographic method with ultraviolet detection has been developed to quantify NB-506 and its active metabolite in human plasma and urine. This method is based on solid-phase extraction, thereby allowing the simultaneous measurement of the drug and metabolite with the limit of quantification of 0.01 microgram/ml in plasma and 0.1 microgram/ml in urine. Standard curves for the compounds were linear in the concentration ranges investigated. The range for the drug in plasma was 0.01-2.5 micrograms/ml, and for the metabolite 0.01-1 microgram/ml. In urine, the range for both compounds was 0.1-10 micrograms/ml. The method was validated and applied to the assay of plasma and urinary samples from phase I studies.