Determination of dextromethorphan and dextrorphan in human urine by high performance liquid chromatography for pharmacogenetic investigations

The aim of the present study was to develop a sensitive method to measure dextromethorphan and dextrorphan in urine by HPLC to support pharmacogenetic studies in ethnic groups. Linearity was assessed in the range: 0.015-10 μg mL-1 for dextromethorphan and 1-10 μg mL ^-1 for dextrorphan. Inter and intra-day coefficients of variation were < 10%. Limits of detection and quantitation were 0.003 μg mL ^-1 and 0.015 μL ^-1 for dextromethorphan and 0.24 μg mL ^-1 and 1.0 μg mL ^-1 for dextrorphan, respectively. The method is reliable in helping determine the phenotype of Mexican ethnic groups using model drugs such as dextromethorphan.