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  • Author: Ruxandra Soare x
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Eleonora Mircia, Gabriel Hancu, Aura Rusu, Adriana Cazacu, Teodora Balaci and Ruxandra Soare

Abstract

Objective: In this study we report the development of a simple, rapid and efficient capillary electrophoresis method for the simultaneous determination of atorvastatin, fluvastatin, lovastatin and simvastin.

Methods: Capillary zone electrophoresis proved to be efficient for the simultaneous separation of atorvastatin and fluvastatin, but could not resolve the determination of lovastatin and simvastatin. The simultaneous separation of all four statins was achieved by applying a micellar electrokinetic chromatographic method, after transforming lovastatin and simvastatin in β-hydroxyl acid forms through alkaline hydrolysis. The optimum electrophoretic conditions and analytical parameters were investigated and the analytical performances of the method were verified with regard to linearity, precision, accuracy, LOD and LOQ.

Results: The optimum electrophoretic separation conditions were: 25 mM sodium tetraborate with 25 mM sodium dodecyl sulphate buffer electrolyte at pH 9.5, applied voltage + 25 kV, separation temperature 25 °C, injection pressure/time 50 mbar/1 minutes, UV detection at 230 nm. Using the optimized electrophoretic conditions we succeeded in the simultaneous determination of the four statins in approximately 3 minutes, the order of migration being: atorvastatin, fluvastatin, lovastatin, simvastatin. The proposed method has been applied to the determination of the analytes in pharmaceutical tablets formulations.

Conclusions: The capillary electrophoretic method developed in the present work proved to be suitable for the routine analysis of statins and can be adopted as quality control protocol in pharmaceutical analysis.

Open access

Eleonora Mircia, Laurian Vlase, Gabriel Hancu, Monica Budău and Ruxandra Soare

Abstract

Pentoxifylline is a xanthine derivative used in the treatment of peripheral vascular disease, which because of its pharmacokinetic and pharmacologic profile is an ideal candidate for the development of extended release formulations. The aim of this study is to present a kinetic analysis of the pentoxifylline release from different extended release tablets formulations, using mechanistic and empirical kinetic models. A number of 28 formulations were prepared and analysed; the analysed formulations differed in the nature of the matrix forming polymers (hydrophilic, lipophilic, inert) and in their concentrations. Measurements were conducted in comparison with the reference product Trental 400 mg (Aventis Pharma). The conditions for the dissolution study were according to official regulations of USP 36: apparatus no. 2, dissolution medium water, volume of dissolution medium is 1,000 mL, rotation speed is 50 rpm, spectrophotometric assay at 274 nm. Six mathematical models, five mechanistic (0 orders, 1st-order release, Higuchi, Hopfenberg, Hixson-Crowell) and one empirical (Peppas), were fitted to pentoxifylline dissolution profile from each pharmaceutical formulation. The representative model describing the kinetics of pentoxifylline release was the 1st-order release, and its characteristic parameters were calculated and analysed.

Open access

Adriana Modroiu, Gabriel Hancu, Robert Alexandru Vlad, Ștefana Stăcescu, Ruxandra Soare and Hajnal Kelemen

Abstract

A rapid, simple and sensitive capillary zone electrophoresis method was developed for the simultaneous determination of amlodipine besylate and telmisartan, in fixed-dose combinations, through the utilization of a UV photodiode array detector. Electrophoretic parameters such as buffer concentration and pH, system temperature, applied voltage and injection parameters, were optimized in order to improve the efficiency of the separation. The best results were obtained when employing fused silica capillary (48 cm length X 50 μm ID) and 50 mM phosphate buffer electrolyte at pH 4.50, + 25 kV applied voltage, as well as 25°C system temperature. The separation was achieved in approximately 3 minutes, with a resolution of 4.90, while the order of migration was amlodipine followed by telmisartan. The analytical performance of the method was verified with regard to linearity, precision and robustness. In addition, the limit of detection and the quantification were calculated.