Development and Evaluation of Candesartan Sustained Release Matrix Tablets

Abstract

This study was undertaken to formulate and evaluate sustained-release matrix tablets of candesartan using Carbopol 934P in combination with chitosan or sodium alginate as release-modifying polymers. Candesartan, an angiotensin II receptor type-1 antagonist, was selected because its reported shorter half-life and need for repeated administration make it a suitable candidate for prolonged-release delivery. A UV spectrophotometric method was used for drug estimation, with a maximum absorption wavelength of 258 nm in methanol. Drug–excipient compatibility was assessed by FT-IR spectroscopy. Seven matrix formulations (F1–F7) containing 80 mg candesartan were prepared by direct compression using Carbopol 934P, chitosan or sodium alginate, polyvinylpyrrolidone K30, microcrystalline cellulose, talc and magnesium stearate. Powder blends showed acceptable flow characteristics, with angle of repose values of 25.33–31.43°, Carr’s index of 7.27–18.42% and Hausner’s ratio of 1.053–1.240. The compressed tablets exhibited acceptable physical characteristics, drug content of 98.25–101.61% and friability below 1%. In-vitro dissolution testing was performed for 24 h using USP type II apparatus. F4 and F7, containing the highest levels of chitosan and sodium alginate, respectively, provided the most prolonged release, reaching 99.54% and 98.78% drug release at 24 h. Release-kinetic analysis indicated first-order kinetics, while Korsmeyer–Peppas analysis suggested a non-Fickian release mechanism. F4 and F7 remained physically and chemically acceptable during the reported three-month stability study. The findings demonstrate the potential of polymer–crosslinking-agent combinations for extending candesartan release.