title: Determination of risperidone and its major metabolite 9-hydroxyrisperidone in human plasma by reversed-phase liquid chromatography with ultraviolet detection.
abstract: A simple and sensitive high-performance liquid chromatographic (HPLC) method with UV absorbance detection is described for the quantitation of risperidone and its major metabolite 9-hydroxyrisperidone in human plasma, using clozapine as internal standard. After sample alkalinization with 1 ml of NaOH (2 M) the test compounds were extracted from plasma using diisopropyl ether-isoamylalcohol (99:1, v/v). The organic phase was back-extracted with 150 microl potassium phosphate (0.1 M, pH 2.2) and 60 microl of the acid solution was injected into a C18 BDS Hypersil analytical column (3 microm, 100x4.6 mm I.D.). The mobile phase consisted of phosphate buffer (0.05 M, pH 3.7 with 25% H3PO4)-acetonitrile (70:30, v/v), and was delivered at a flow-rate of 1.0 ml/min. The peaks were detected using a UV detector set at 278 nm and the total time for a chromatographic separation was about 4 min. The method was validated for the concentration range 5-100 ng/ml. Mean recoveries were 98.0% for risperidone and 83.5% for 9-hydroxyrisperidone. Intra- and inter-day relative standard deviations were less than 11% for both compounds, while accuracy, expressed as percent error, ranged from 1.6 to 25%. The limit of quantitation was 2 ng/ml for both analytes. The method shows good specificity with respect to commonly prescribed psychotropic drugs, and it has successfully been applied for pharmacokinetic studies and therapeutic drug monitoring.
authors.affiliation: Institute of Pharmacology, School of Medicine, University of Messina, Policlinico Universitario, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Avenoso
authors.forename: G
authors.initials: G
authors.lastname: Facciolà
authors.forename: M
authors.initials: M
authors.lastname: Salemi
authors.forename: E
authors.initials: E
authors.lastname: Spina
mesh_terms: D014150:Antipsychotic Agents / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D007555:Isoxazoles / Q000097:blood*; D000068882:Paliperidone Palmitate; D011743:Pyrimidines / Q000097:blood*; D015203:Reproducibility of Results; D018967:Risperidone / Q000097:blood*; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet
chemical_list: D014150:Antipsychotic Agents; D007555:Isoxazoles; D011743:Pyrimidines; D018967:Risperidone; D000068882:Paliperidone Palmitate