Determination of risperidone and 9-hydroxyrisperidone in human plasma by liquid chromatography: application to the evaluation of CYP2D6 drug interactions (original) (raw)
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Journal of Chromatography B: Biomedical Sciences and Applications, 1992
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 of quantitation was 5 nmol / L, and the inter-day coefficient of variation was less than 8% for both compounds. The mean recoveries of risperidone and 9-hydroxyrisperidone added to plasma were 96.8 and 99.4%, with an intra-day coefficient of variation of under 5 and 6%, respectively. Studies of analytical interference showed that the most commonly co-administered antidepressants and benzodiazepines did not interfere. The method was used for the determination of the plasma concentrations of a schizophrenic patient treated daily with an oral dose of 4.5 mg risperidone. The patient suffered severe extrapyramidal side-effects after adding risperidone to his previous medication of haloperidol and levomepromazine. The risperidone plasma concentration was well above the average (182 nmol / L), which suggests that a pharmacokinetic interaction occurred, presumably due to inhibition of the enzyme CYP2D6.
Journal of psychopharmacology (Oxford, England), 2016
Treatment of arterial hypertension in patients with severe mental illnesses often results in polypharmacy, potentially leading to drug-drug interactions. The objective of the study was to analyse the in vivo inhibitory potential of two antihypertensive drugs, amlodipine and metoprolol on CYP2D6 catalysed 9-hydroxylation of risperidone (RIS). A therapeutic drug monitoring database with plasma concentrations of RIS and 9-hydroxyrisperidone (9-OH-RIS) of 1584 patients was analysed. Three groups were considered; a group of patients receiving RIS without a potentially cytochrome influencing co-medication (control group, R0, n=852), a group co-medicated with amlodipine (RA, n=27) and a group, co-medicated with metoprolol (RM, n=41). Plasma concentrations, concentration-to-dose ratios (C/Ds) of RIS, 9-OH-RIS and the active moiety (AM), as well as the metabolic ratios were computed and compared using the Kruskal-Wallis test, the Mann-Whitney U test and the Jonckheere-Terpstra test to determ...
Risperidone metabolism in relation to CYP2D6*10 allele in Korean schizophrenic patients
European Journal of Clinical Pharmacology, 2001
Objective: Risperidone is known to be biotransformed to its active metabolite, 9-hydroxyrisperidone, by the polymorphic CYP2D6 in Caucasians. This study aimed to investigate the relationship between the CYP2D6*10 allele and the plasma levels of risperidone and 9-hydroxyrisperidone in Korean schizophrenic patients. Methods: Eighty-two Korean schizophrenic patients in monotherapy with oral doses of risperidone from 1 mg/ day to 8 mg/day (mean SD 4.31.9, median 4) participated in this study. Plasma concentrations of risperidone and 9-hydroxyrisperidone were analyzed using high-performance liquid chromatography. The CYP2D6*10 allele, which contains C188T mutation in exon 1, was identi®ed using allele-speci®c polymerase chain reaction ampli®cation. Results: Seventeen of 82 patients were homozygous for CYP2D6*1, 22 for *10, while the remaining 43 patients were heterozygous for these alleles. The plasma levels of risperidone and 9-hydroxyrisperidone ranged from 1.0 nM to 168 nM and 6.2 nM to 235 nM, respectively. The median concentrations/dose (C/Ds) (range) of risperidone in CYP2D6*1/*1, *1/*10, and *10/*10 groups were 1.7 (0.2±7.9), 2.6 (0.3±27.1), and 6.7 nM/mg (2.4± 21.0), respectively. There was a statistically signi®cant dierence among the three genotypes (Kruskal-Wallis test, P<0.001). For 9-hydroxyriperidone, the corresponding median C/Ds were 13.1 (3.3±25.4), 11.9 (4.2± 30.8), and 13.6 nM/mg (6.5±52.8), respectively, with no signi®cant dierence between the genotypes (P=0.54). The medians of the ratios between risperidone and 9hydroxyrisperidone concentrations were 0.13 (0.01± 0.93), 0.28 (0.01±2.77), and 0.46 nM/mg (0.05±1.28) in *1/*1, *1/*10, and *10/*10 genotypes, respectively, and they were signi®cantly dierent (P=0.004). The active moieties (sum of the C/Ds of risperidone and 9-hydroxyrisperidone) were not signi®cantly dierent between the genotypes (P=0.063). Conclusion: In Korean schizophrenic patients, the metabolism of risperidone is dependent on CYP2D6, and the CYP2D6*10 allele is important for the regulation of the activity of this enzyme. There were no signi®cant dierences in the plasma concentration of parent drug plus its active metabolite between the genotypes. This suggests that the clinical signi®cance of this polymorphism is limited. Our study con®rms previous studies on risperidone metabolism in Caucasians.
Journal of Chromatography B: Biomedical Sciences and Applications, 2000
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 ml potassium phosphate (0.1 M, pH 2.2) and 60 ml of the acid solution was injected into a C BDS Hypersil analytical column (3 mm, 10034.6 mm 18 I.D.). The mobile phase consisted of phosphate buffer (0.05 M, pH 3.7 with 25% H PO)-acetonitrile (70:30, v / v), and was 3 4 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.
PRILOZI, 2018
Atypical antipsychotic risperidone is widely used first-line monotherapy in schizophrenia and combined therapy in bipolar disorders. Therapeutic plasma concentrations of risperidone and its active moiety are directly influenced by genetic variations in metabolic CYP450 enzymes (CYP2D6 and CYP3A4/5) and transporter (ABCB1) protein and additional environmental factors. Since active metabolite 9-OH risperidone has a greater percentage of the pharmacologically active fraction and is equipotent to the parent drug risperidone, it is assumed that it contributes significantly to therapeutic and adverse effects. Unpredictable dose/concentration ratio, narrow therapeutic index, number of interactions, along with serious adverse reactions (ADR), raises the need for individualization of risperidone treatment and establishing of good therapeutic regime using TDM. A simple and reliable validated bioanalytical liquide-liquide extraction HPLC/UV method was applied for the simultaneous determination...
Risperidone plasma levels, clinical response and side–effects
European Archives of Psychiatry and Clinical Neuroscience, 2005
■ Abstract Introduction Assessment of the relation between oral risperidone dose, serum drug levels and clinical response may provide important information for rational treatment decisions. Inter-individual differences in the liver cytochrome P450 system, especially in the CYP2D6 subsystem, which account for a significant portion of risperidone metabolism, may also influence plasma drug levels and alter clinical response parameters. We thus prospectively investigated risperidone serum concentrations in relation to clinical efficacy and side-effects and genotyped major CYP2D6 polymorphisms to determine their effect upon these parameters. Methods Neuroleptic monotherapy with risperidone was administered to schizophrenia patients in a 6-week open dose clinical trial. Weekly assessments including CGI and PANSS ratings to assess psychopathology; SAS to assess medication side effects; and blood draws to quantify steady state plasma levels of risperidone and 9-OH-risperidone were carried out. In addition, major CYP2D6 polymorphisms including alleles *4, *6 and *14 were genotyped. Results Eighty-two patients were recruited. Mean oral dose of risperidone was 4.3 ± 0.9 mg. Mean plasma level of both risperidone and 9-OH-risperidone together ("active moiety") was 41.6 ± 26.6 ng/ml. Significant improvements in PANSS scales and the various subscales ensued. There was a positive linear correlation between active moiety plasma levels and dose (r = 0.291, p = 0.015) and be-tween risperidone and 9-OH-risperidone levels (r = 0.262; p = 0.016). Nonresponders to pharmacotherapy (PANSS-Improvement < 30 %) showed significantly higher active moiety plasma levels (49.9 ± 30.7 ng/ml) than responders (38.2 ± 17.0 ng/ml; p = 0.045) without significantly higher oral doses (p = 0.601). Patients with longer illness duration (≥ 3 years) had significantly higher plasma drug levels than those with a shorter course (< 3 years; p = 0.039). Extrapyramidal side effects (EPS) and plasma levels were not correlated (r = 0.028; p = 0.843), but higher plasma levels at week 2 predicted an incidence for EPS (p < 0.050). Accordingly, patients initially receiving higher oral doses of risperidone were significantly more likely to respond with EPS in the trial course. Eight patients (9.8 %) were heterozygous carriers of the CYP2D6 allele *4.CYP2D6 polymorphisms did not predict clinical response, but predicted a tendential increase in the plasma risperidone to 9-OH-risperidone ratio (0.5 ± 0.6 vs. 1.9 ± 1.8; p = 0.120). Discussion The major finding was that responders to risperidone treatment had significantly lower blood levels of risperidone and 9-OH risperidone than patients who did not respond to the treatment despite administration of similar oral doses. The observed CYP2D6 polymorphisms did not contribute to altered clinical efficacy, but affected risperidone to 9-OH-risperidone ratios. Increased plasma levels of the active moiety in patients with longer illness may represent general aging effects. Conversely, the observed higher plasma levels in nonresponders may derive from unaccounted genetic metabolism abnormalities or Phase II metabolism disturbances. Patients initially receiving higher oral risperidone doses were more likely to respond with extrapyramidal side effects which reaffirms the need for careful titration. The high inter-individual variability in risperidone and 9-OH-risperidone metabolization and the relationship between clinical outcome and plasma levels warrants regular plasma level monitoring of both compounds to assess for the clinically relevant active moiety.
Plasma protein binding of risperidone and its distribution in blood
Psychopharmacology, 1994
The plasma protein binding of the new antipsychotic risperidone and of its active metabolite 9-hydroxy-risperidone was studied in vitro by equilibrium dialysis. Risperidone was 90.0% bound in human plasma, 88.2% in rat plasma and 91.7% in dog plasma. The protein binding of 9-hydroxy-risperidone was lower and averaged 77.4% in human plasma, 74.7% in rat plasma and 79.7% in dog plasma. In human plasma, the protein binding of risperidone was independent of the drug concentration up to 200 ng/ml. The binding of risperidone increased at higher pH values. Risperidone was bound to both albumin and ex-acid glycoprotein. The plasma protein binding of risperidone and 9-hydroxy-risperidone in the elderly was not significantly different from that in young subjects. Plasma protein binding differences between patients with hepatic or renal impairment and healthy subjects were either not significant or rather small. The blood to plasma concentration ratio of risperidone averaged 0.67 in man, 0.51 in dogs and 0.78 in rats. Displacement interactions of risperidone and 9-hydroxyrisperidone with other drugs were minimal.
Therapeutic Drug Monitoring, 2001
Two published case reports showed that addition of risperidone (1 and 2 mg/d) to a clozapine treatment resulted in a strong increase of clozapine plasma levels. As clozapine is metabolized by cytochrome P450 isozymes, a study was initiated to assess the in vivo interaction potential of risperidone on various cytochrome P450 isozymes. Eight patients were phenotyped with dextromethorphan (CYP2D6), mephenytoin (CYP2C19), and caffeine (CYP1A2) before and after the introduction of risperidone. Before risperidone, all eight patients were phenotyped as being extensive metabolizers of CYP2D6 and CYP2C19. Risperidone at dosages between 2 and 6 mg/d does not appear to significantly inhibit CYP1A2 and CYP2C19 in vivo (median plasma paraxanthine/caffeine ratios before and after risperidone: 0.65, 0.69; p ס 0.89; median urinary (S)/(R) mephenytoin ratios before and after risperidone:0.11, 0.12; p ס 0.75) . Although dextromethorphan metabolic ratio is significantly increased by risperidone (median urinary dextromethorphan/dextrorphan ratios before and after risperidone: 0.010, 0.018; p ס 0.042), risperidone can be considered a weak in vivo CYP2D6 inhibitor, as this increase is modest and none of the eight patients was changed from an extensive to a poor metabolizer. The reported increase of clozapine concentrations by risperidone can therefore not be explained by an inhibition of CYP1A2, CYP2D6, CYP2C19 or by any combination of the three.
Therapeutic Drug Monitoring, 2009
The aim of this study was to assess a method able to analyze serum levels of risperidone (RIS) and its metabolite, 9-hydroxyrisperidone (9-OH-RIS), and to investigate possible relationships between changes in serum concentrations of these drugs and clinical measures, so to identify early markers of treatment response. The authors developed a sensitive and specific liquid chromatography-tandem mass spectrometry method to measure RIS and its metabolite in serum. Fifteen RIS-naive patients were admitted to an acute psychiatric care unit and treated with 4-6 mg/d oral RIS. At days 7 and 21 of hospital stay, serum levels were measured; clinical scales and serum prolactin were assessed. RIS and its metabolite were analyzed by a Q-Trap 2000 triple quadrupole/ion trap mass spectrometer in the multiple reaction-monitoring mode. Chromatographic separation was accomplished using a cyano column with an analytical run of 9 minutes. The calibration curve exhibited consistent linearity and reproducibility in the range 0-100 ng/mL for both analytes. Lower limit of quantification was 0.2 ng/mL; limit of detection, for a signal to noise ratio of 3, was 0.05 ng/mL for both analytes. Serum RIS and 9-OH-RIS levels increased at day 7, reaching a steady state, and remaining constant up to day 21. Scores on psychopathology rating scales decreased; serum prolactin and neurological rating scale for extrapyramidal effects rose at day 7 and remained stable thereafter. No correlation was found between serum concentration values, including sum and ratio of RIS and 9-OH-RIS, and any of the other clinical values (serum prolactin and clinical scales). These data indicate that clinical changes are related to the achievement of steady state levels of RIS and its metabolite and are maintained, but not continued, with continued RIS treatment. Therapeutic drug monitoring of RIS and its metabolites is not recommended as a routine procedure in patients with psychotic disorders.