Determination of risperidone and 9-hydroxyrisperidone in human plasma by liquid chromatography: application to the evaluation of CYP2D6 drug interactions.

摘要: Abstract A high-pressure liquid chromatography with ultra-violet detection method for the simultaneous determination of risperidone and 9-hydroxyrisperidone in plasma after liquid–liquid extraction has been developed. The limit quantitation was 5 nmol/L, inter-day coefficient variation less than 8% both compounds. mean recoveries added to were 96.8 99.4%, an intra-day under 6%, respectively. Studies analytical interference showed that most commonly co-administered antidepressants benzodiazepines did not interfere. used concentrations a schizophrenic patient treated daily oral dose 4.5 mg risperidone. suffered severe extrapyramidal side-effects adding his previous medication haloperidol levomepromazine. concentration well above average (182 nmol/L), which suggests pharmacokinetic interaction occurred, presumably due inhibition enzyme CYP2D6.