Pharmacokinetics and bioequivalence of 2 tablet formulations of olanzapine in healthy Chinese volunteers: a randomized, open-label, single-dose study

Comparative, Single-Dose, 2-Way Cross-Over Bioavailability Study of Two Olanzapine 10 Mg Tablet Formulations in Healthy Volunteers Under Fasting Conditions

Objectives: Olanzapine is an atypical antipsychotic that is approved across Europe, the USA, and in many other countries for oral treatment of schizophrenia and acute manic episodes in patients with bipolar disorder as well as for maintenance therapy to prevent recurrence in responders. The objective of the present study was to compare the pharmacokinetics of two 10 mg tablet formulations of Olanzapine following a single oral dose in healthy volunteers under fasting conditions, as per the European Medicine Agency (EMA) guidelines to grant marketing authorization. Methods: This study was a randomized, open-label, two-treatment, two-period, two-sequences, single-dose, cross-over design with a washout period of 14 days. Both the test and the reference products were administered as 10 mg tablets with 240 mL of water after an overnight fast in each study period. A total of twenty blood samples were collected before dosing and within 144 hours after drug administration. Adverse events were monitored, recorded, and evaluated by investigators throughout the study. Results: Of the 24 healthy adult male subjects enrolled, all of them completed both study periods. The geometric mean ratio 90% confidence intervals (CI) for fasting Cmax, AUC0-t, and AUC0-infinity were 94.83-113.71%, 95.04-105.69% and 95.94-107.00%, respectively. The 90% CI for the ratios of the three primary pharmacokinetic parameters (using log-transformed data) were within the range of 80-125%, meeting the regulatory criteria for bioequivalence. Conclusions: The generic Olanzapine was bioequivalent to the reference formulation. It was well tolerated and provides an acceptable alternative to the reference drug.

Pharmacokinetics and Bioequivalence of 2 Olanzapine Orally Disintegrating Tablet Products in Healthy Chinese Subjects Under Fed and Fasting Conditions

To assess the bioequivalence of two 5-mg olanzapine orally disintegrating tablet (ODT) products, 2 randomized, open-label, single-dose, 2-way crossover studies were carried out under fasting or fed conditions. Blood samples were collected at scheduled times according to the study protocol. Statistical analysis of area under the concentration-time curve from time 0 to 168 hours (AUC_0-t ), area under the curve from time zero to infinity (AUC_0-∞ ), and peak plasma concentration (C_max ) was conducted. Two formulations were considered bioequivalent if the 90% confidence intervals (CIs) of the geometric mean ratios for AUC_0-t, AUC_0-∞ , and C_max were within the range of 0.80-1.25. Adverse events were recorded and evaluated throughout the studies. A total of 48 subjects with 24 in each study completed the 2 studies. In fasted subjects, the 90%CIs for the test product versus the reference product were 97.28%-105.13% for AUC_0-t , 97.57%-105.54% for AUC_0-∞ , and 90.94%-103.97% for C_max . In fed subjects, the 90%CIs for AUC_0-t , AUC_0-∞ and C_max were 99.73%-122.63%, 99.56%-121.75%, and 99.46%-120.46%, respectively. No serious adverse events were reported in the studies. The reference and the test product of 5-mg olanzapine ODT show comparable pharmacokinetic profiles under both fed and fasted conditions and were considered bioequivalent.

Population pharmacokinetics analysis of olanzapine for Chinese psychotic patients based on clinical therapeutic drug monitoring data with assistance of meta-analysis

PURPOSE

The aim of this study was to build an eligible population pharmacokinetic (PK) model for olanzapine in Chinese psychotic patients based on therapeutic drug monitoring (TDM) data, with assistance of meta-analysis, to facilitate individualized therapy.

METHODS

Population PK analysis for olanzapine was performed using NONMEM software (version 7.3.0). TDM data were collected from Guangzhou Brain Hospital (China). Because of the limitations of TDM data, model-based meta-analysis was performed to construct a structural model to assist the modeling of TDM data as prior estimates. After analyzing related covariates, a simulation was performed to predict concentrations for different types of patients under common dose regimens.

RESULTS

A two-compartment model with first-order absorption and elimination was developed for olanzapine oral tablets, based on 23 articles with 390 data points. The model was then applied to the TDM data. Gender and smoking habits were found to be significant covariates that influence the clearance of olanzapine. To achieve a blood concentration of 20 ng/mL (the lower boundary of the recommended therapeutic range), simulation results indicated that the dose regimen of olanzapine should be 5 mg BID (twice a day), ≥ 5 mg QD (every day) plus 10 mg QN (every night), or >10 mg BID for female nonsmokers, male nonsmokers and male smokers, respectively.

CONCLUSION

The population PK model, built using meta-analysis, could facilitate the modeling of TDM data collected from Chinese psychotic patients. The factors that significantly influence olanzapine disposition were determined and the final model could be used for individualized treatment.

The development and validation of a method for quantifying olanzapine in human plasma by liquid chromatography tandem mass spectrometry and its application in a pharmacokinetic study

1. A rapid method using liquid chromatography tandem mass spectrometry for the quantification of olanzapine (OLZ) in human plasma was developed and validated. Venlafaxine was used as the internal standard (IS), and the samples were extracted from 400-μL human plasma with methyl tert-butyl ether for liquid-liquid extraction. 2. Chromatography was performed using an ACE C18, 125 × 4.6-mm i.d., 5-μm column. The mobile phase consisted of water with 0.1% formic acid for solvent A and acetonitrile with 0.1% formic acid for solvent B (50 : 50 v/v) in isocratic mode. The flow rate was 1.2 mL/min. The retention times for OLZ and the IS were 0.78 and 1.04 min, respectively. Tandem mass spectrometry operating in positive electrospray ionization mode with multiple reaction monitoring was used to detect OLZ and the IS (m/z: 313.1 > 256.1 and 278.1 > 260.2, respectively). 3. No significant matrix effects were observed on OLZ and the IS retention times, and the mean recovery of OLZ was 90.08%. The assay was linear in the concentration range of 1-20 ng/mL (R(2) = 0.9976). The intra- and inter-day precision were < 11.60% and the accuracy was < 1.66%. 4. This validated method was successfully applied to a pharmacokinetic study in which 10-mg OLZ tablets were administered to healthy volunteers and their plasma OLZ levels were monitored over time. The tests showed that the OLZ test and reference drug (Zyprexa(®)) were bioequivalent, as 90% of the confidence intervals were within the 80-125% interval proposed by regulatory agencies.