A high-performance liquid chromatographic-atmospheric pressure chemical ionization-tandem mass spectrometric method for determination of risperidone and 9-hydroxyrisperidone in human plasma.

Risperidone, a benzisoxazole derivative, is an antipsychotic agent used for the treatment of schizophrenia. We developed a liquid chromatographic-atmospheric pressure chemical ionization-tandem mass spectrometric (LC-APCI-MS-MS) method with improved sensitivity, selectivity, and dynamic range for determination of risperidone and 9-hydroxyrisperidone in human plasma. A structural analogue of risperidone, RO68808 (5 ng/mL), is added as the internal standard to 1 mL of human plasma.

A liquid chromatographic-electrospray ionization-tandem mass spectrometric method for determination of buprenorphine, its metabolite, norbuprenorphine, and a coformulant, naloxone, that is suitable for in vivo and in vitro metabolism studies.

A liquid chromatographic-electrospray ionization-tandem mass spectrometric method has been developed and validated for determination of the antiabuse medication, buprenorphine, its primary metabolite, norbuprenorphine, and a proposed coformulant, naloxone. The method uses deuterated internal standards and a simple liquid-liquid extraction. Mass spectrometry employed selected reaction monitoring of the transitions of m/z 468 to 396 for buprenorphine, 472 to 400 for [2H4]buprenorphine, 414 to 101 for norbuprenorphine, 423 to 110 for [2H9]norbuprenorphine, 328 to 310 for naloxone, and 345 to 327 for its internal standard, [2H3]naltrexone.