RESUMO
In this work, the dissolution profiles of nine meloxicam tablet brands marketed in Argentina have been evaluated. As meloxicam is a Class 2 Biopharmaceutical Classification System (BSC) drug, interchangeability between commercial products must be demonstrated through in vivo bioequivalence studies. However, in our country, such studies remain to be performed. Dissolution studies have been performed according to USP 38 and evaluated by fitting experimental data to the zero and first-order, the Hixson-Crowell, the Higuchi, and the Weibull model-dependent methods. To test the pertinence of these release models, the Akaike Information Criteria (AIC) were used. All brands satisfied the dissolution profiles (phosphate buffer, pH 7.5) established in the USP. The comparison between the dissolution profiles was carried out by model-dependent and model-independent methods. The Weibull model provided the best kinetic curve adjustment. Brands I, II, IV and VI had the best fitting, with the maximum determination coefficient and the smallest AIC values. Model-independent methods included ratio test and the fit factors. The Dissolution Efficiency (DE) and Mean Dissolution Time (MDT) were analysed with ANOVA and the DGC method. In both cases, brand I did not show similarity with the rest of the brands. Using fit factors, only brands I, II and V were similar to each other. Significant differences were found among the in vitro dissolution profiles of meloxicam tablets belonging to the nine brands. As meloxicam is a class 2 BCS drug, interchangeability between commercial products must be demonstrated through in vivo bioequivalence studies. However, in Argentina, such studies remain to be performed. Our results demonstrate that caution must be exercised as regards interchangeability of generic products.
RESUMO
Simple, sensitive, and economical simultaneous volumetric and HPLC methods for the determination of pridinol mesylate in raw material have been developed. The volumetric method is based on the reaction of pridinol with sodium lauryl sulphate in diluted sulphuric acid. Dimethyl yellow was used as indicator to detect the end point of the titration in aqueous/organic layer. The HPLC method for the determination of pridinol mesylate employs a reverse phase C18 column at ambient temperature with a mobile phase consisting of acetonitrile: 0.05 M potassium dihydrogen phosphate, pH adjusted to 5.0 (1 : 2, v/v). The flow rate was 0.8 mL/min. Quantitation was achieved with UV detection at 258 nm based on peak area. Both methods were found to be suitable for the quality control of pridinol mesylate in raw material.
RESUMO
An accurate, simple, and reproducible liquid chromatographic method was developed and validated for the determination of tacrolimus in capsules. The analysis is performed at room temperature on a reversed-phase C18 column with UV detection at 210 nm. The mobile phase is methanol-water (90 + 10) at a constant flow rate of 0.8 mL/min. The method was validated in terms of linearity, precision, accuracy, and specificity by forced decomposition of tacrolimus, using acid, base, water, hydrogen peroxide, heat, and light. The response was linear in the range of 0.09-0.24 mg/mL (r2 = 0.9997). The relative standard deviation values for intra- and interday precision studies were 1.28 and 2.91%, respectively. Recoveries ranged from 98.06 to 102.52%.