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Background: Pioglitazone (CAS 112529-15-4 for the HCl form) is an oral antidiabetic agent that is a member of the group of drugs known as thiazolidinediones. It is indicated for the treatment of type 2 diabetes mellitus., Objective: The aim of this study was to assess the bioequivalence of a new pioglitazone 45 mg formulation (test formulation) vs. the reference product, as required by European regulatory authorities for the marketing of a generic product. Additionally, the applicability of the truncated area under the plasma concentration curve (AUC) approach to this drug and under these test conditions was determined., Methods: This was a single-center, randomized, single-dose, open-label, 2-way crossover study in healthy volunteers under fasting conditions. Plasma samples were collected up to 120 h post-dosing. Pioglitazone and hydroxypioglitazone plasma levels were determined by reverse liquid chromatography and by tandem mass spectrometry detection (LC-MS/MS). Pharmacokinetic parameters were calculated using non-compartmental analysis. Area under the concentration-time curve from time zero to time of last non-zero concentration (AUC(last)) and maximum observed concentration (C(max)) were the main evaluation criteria, while the area under the concentration-time curve from time zero to infinity (AUC(inf)) was also analyzed for additional information. For the assessment of the applicability of the truncated AUC approach, AUCs truncated at 24, 48, 72, 96, and 120 h were calculated. All of the abovementioned pharmacokinetic parameters were analyzed using 90% geometric confidence interval of the ratio (T/R) of least-squares means from the ANOVA of the In-transformed parameter. Tolerability was monitored using physical examination, including vital sign measurements and laboratory analysis., Results: According to the classical approach, the 90% geometric confidence intervals obtained by ANOVA for AUC(last), C(max) and AUC(inf) were within the predefined ranges (80-125%) for both analytes. Truncated AUCs were also in all cases within the predefined ranges for acceptance of bioequivalence (e.g. 90% confidence interval)., Conclusion: Bioequivalence between test and reference formulations, both in terms of rate and extension of absorption, under fasting conditions was concluded according to European guidelines. Both formulations were well tolerated. The conclusion of bioequivalence was also supported using the truncated AUCs approach.

The need for a reliable bioanalytical method is of primary importance during preclinical studies. The aim of the present study was simultaneous determination of pioglitazone (CAS 111025-46-8) (PIO) and glimepiride (CAS 93479-97-1) (GLM) in plasma of rats. A high-performance liquid chromatographic method has been developed and validated using C18 column and UV detector. A mobile phase composed of acetonitrile and ammonium acetate buffer pH 4.5 in the ratio of 55:45%. The plasma samples clean-up was carried out using solid phase cartridges. The method was in the linear range of 50-8000 ng/mL for PIO and 50-2000 ng/mL for GLM. The coefficient of regression was found to be > or = 0.99. Precision and accuracy were within the acceptable limits, as indicated by relative standard deviation varying from 1.5 to 6.1% for PIO and 3.1 to 7.0% for GLM whereas the accuracy ranged from 97.0 to 106.4% for PIO and 96.5 to 106.4% for GLM. The mean extraction recovery was found to be 90.2 +/- 4.5, 76.8 +/- 2.8 and 85.2 +/- 5.2% for PIO, GLM and internal standard, respectively. Moreover, PIO and GLM were stable in plasma, up to 30 days of storage at -70 degrees C and after being subjected to bench top, auto-sampler, and three freeze-thaw cycles. The developed method was applied for preclinical pharmacokinetic studies.

A high performance liquid chromatographic (HPLC) method for simultaneous determination of rosiglitazone, CAS 122320-73-4, RSG), cilostazol (CAS 73963-72-1, CLZ) and its active metabolite 3, 4-dehydro-cilostazol (DCLZ), using pioglitazone (PIO) as internal standard (IS), in rat plasma is described. The plasma was extracted with methyl t-butyl ether, the dry extract was reconstituted in mobile phase and the aliquot was injected. The eluent drugs were detected by UV at dual wavelength of 226 nm (RSG and DCLZ) and 257 nm (CLZ). The mobile phase consisting of acetonitrile:potassium di-hydrogen phosphate buffer (35:65 v/v) was used at the flow rate of 1.2 ml/min on a reverse phase C18 column. The absolute recovery was above 90% of all analytes over the concentration range of 25-2500 ng/ml for RSG and CLZ and 20-2000 ng/ ml for DCLZ. The relative standard deviation (RSD) of the inter-day and intra-day precision ranged from 2.8 to 8.4% and 0.9 to 5.9%, respectively. The method is simple, rapid, accurate and sensitive and was applied to pharmacokinetic studies.

A randomized, two-period, two-sequence, crossover study was conducted on 28 healthy male volunteers to compare the bioavailability of two rosiglita-zone (CAS 122320-73-4) tablet formulations, a test and a commercially available original preparation (reference), under fasting conditions. The two preparations were given in a dose of 8 mg with a 7-day washout period between the two preparations. Eighteen blood samples were collected over 24 h, plasma rosiglitazone concentrations were determined by locally validated high performance liquid chromatography (HPLC) assay, and pharmacokinetic parameters were analyzed by the standard non-compartmental method. The mean+/-SD of AUC0-->t, AUC0-->infinity, Cmax, Tmax, and t1/2 were 4.80+/-1.89 and 4.76 +/-1.94 microg x h/ml, 5.17+/-2.11 and 5.08 +/- 2.27 microg x h/ml, 0.93+/-0.24 and 0.99+/-0.34 microg/ml, 1.0 +/-0.4 and 0.8+/-0.5 h, and 5.0+/-2.0 and 5.0+/-2.0 h for the test and reference formulation, respectively. ANOVA did not show significant formulation, period, or sequence effect for any of the pharmacokinetic parameters. The 90 % confidence intervals of the mean differences between log-transformed values of the two formulations were 93.09 % to 109.73 %, 94.04 % to 111.70 %, and 89.70 % to 103.24 % for AUC0-->t, AUC-->infinity, and Cmax, respectively. It is concluded that the two formulations are equivalent in relation to the rate and extent of absorption.

The study was designed to evaluate the bioequivalence of two pioglitazone (CAS 112529-15-4) formulations. The trial was performed in 26 healthy male volunteers with the aim of comparing a new generic product (tablets containing 30 mg pioglit-azone hydrochloride, test) with the originator product (reference). The trial was performed according to an open, crossover design in one study centre. In each of the two study periods (separated by a wash-out of 14 days) a single oral dose of 30 mg (test or reference) formulation was administered. Blood samples were taken up to 120 h post dose, the plasma was separated and the concentrations of pioglitazone and its principal active metabolite hydroxypioglitazone were determined by LC-MS-MS method. AUC0-inf, AUC0-t, Cmax, and Tmax were calculated for both formulations. The mean Cmax of pioglitazone ranged between 1.01 microg/mL and 1.05 microg/mL, while the mean AUC0-inf and AUC0-t ranged between 10.89 microg x h/mL and 10.98 microg x h/mL as well as between 10.56 microg x h/mL and 10.62 microg x h/mL for the test and reference formulations, respectively. The median Tmax for the test tablets was 1.50 h and for the reference was 1.75 h. The ratios test/reference formulation for AUC0-inf, AUC0-t and Cmax were 99.70%, 100.13% and 99.17%, respectively. Furthermore, the 90% geometric confidence intervals of the mean ratio of In-transformed AUC0-inf were narrow and symmetrical around 100%, i.e. 90.59% to 109.72%, for AUC0-t, 90.69% to 110.55%, whereas for Cmax they were 87.52% to 112.37%. As in the case of pioglitazone, mean values of the principal bioequivalence parameters of hydroxypioglitazone did not differ significantly after administration of the test and reference formulations. In the light of the present study it can be concluded that the two evaluated pioglitazone formulations, i.e. test formulation of pioglitazone hydrochloride and reference formulation, are bioequivalent in terms of the rate and extent of absorption.