A new, simple, precise, rapid, and selective high-performance thin-layer chromatographic (HPTLC) method is developed for the simultaneous analysis of amlodipine and benazepril in pharmaceutical formulations. The method uses zolpidem as an internal standard (IS). The stationary phase used is silica gel 60 F254 prewashed with methanol. The mobile phase consists of an ethyl acetate-methanol-ammonia solution (8.5:2.0:1.0, v/v/v). Detection and quantitation are performed densitometrically at lambda = 254 nm. The Rf values of amlodipine, benazepril, and zolpidem (IS) are 0.58, 0.50, and 0.78, respectively. The limits of detection of amlodipine and benazepril are 0.02 and 0.2 microg; linearity ranges are 0.1-0.8 and 0.2-2.0 microg; and the percentage recoveries are 99.79% and 100.25%, respectively.

This study aims to evaluate the feasibility of producing acyclovir-containing modified release matrix tablets by a wet granulation method based on the type and concentration of two pharmaceutical-grade hydrophilic matrix polymers (i.e., hydroxypropyl methylcellulose (HPMC), carbomers, and their combinations) commonly used in biomedical applications. The mechanical properties of the tablets and in vitro and in vivo performance were studied. The physicochemical properties of the raw materials and corresponding physical mixtures were characterized by differential scanning calorimetry, showing that the hydrophilic polymers did not influence the physicochemical properties of the drug. The wet granulation process improved the flow and compression properties of the obtained granules. This method enabled the preparation of the matrix tablets of acyclovir with appropriate mechanical properties concerning hardness and friability. The drug release kinetics was governed by the type and concentration of the hydrophilic polymers composing the matrices. The study has proven that HPMC-composed tablets were superior in modified drug release properties compared to carbomer- and HPMC/carbomer-based tablets. Mathematical analysis of the release profiles, determined in a medium adjusted to pH 1.2 followed by pH 7.4, revealed that the drug released from the hydrophilic tablets followed non-Fickian first-order kinetics. An optimal HPMC-based formulation submitted to accelerated stability studies (40 °C, 75% RH) was stable for three months. A complete cross-over bioavailability study of the selected acyclovir-loaded sustained release tablets and marketed immediate-release tablets were compared in six healthy male volunteers. The extent of drug absorption from the sustained release tablets was significantly greater than that from immediate-release pills, which may improve the drug’s antiviral properties attributed to the lower elimination rate and enhanced acyclovir half-life.

The objective of the present investigation was to develop and evaluate sustained release matrix tablets of prochlorperazine maleate employing different types and levels of hydrophilic matrix agents namely hydroxyl propyl methyl cellulose (HPMC), carbopol and combination of these polymers by wet granulation technique. Prior to compression process, the prepared granules were evaluated for its flow and compression characteristics. The in vitro dissolution of the newly formulated sustained release tablets were compared with standard formulation. The excipients used in this study did not alter the physicochemical properties of the drug, as indicated by the thermal analysis using differential scanning calorimetry technique. The flow and compression characteristics of the prepared granules significantly improved by virtue of granulation process. Also, the prepared matrix tablets showed good mechanical properties in terms of hardness and friability. HPMC based tablet formulations alone showed high release retarding efficiency as compared to carbopol, carbopol and HPMC combinations. The studies indicated that the drug release can be modulated by varying concentrations of polymers. Mathematical analysis of the release kinetics indicated the nature of the drug release from the matrix tablets followed quasi-fickian obeying first order kinetics.