Design and evaluation of mucoadhesive buccal delivery systems of felodipine

Abstract

The objective of the present work was to design and evaluate mucoadhesive newlinebuccal drug delivery systems of felodipine (FDP). FDP, a 1,4-dihydropyridine newlinederivative, is a vasoselective calcium antagonist widely used in treatment of angina newlinepectoris and hypertension. The drug exists as crystalline powder and is very slightly newlinesoluble in water. Orally administered FDP has poor bioavailability due to extensive newlinefirst pass metabolism and is erratically absorbed. newlineIn the present research work, modified release buccal tablets of FDP were newlinedesigned using various mucoadhesive polymers and process excipients in an effort to newlineincrease bioavailability. Prior to the formulation of tablets, solubility of FDP was newlineenhanced by preparing solid dispersions and nanocrystals of the drug. The effect of newlinesolubility enhancement on in vitro release and bioavailability of FDP was observed by newlinepreparing buccal tablets using pure drug, solid dispersions and nanocrystals. newlineAnalytical methods were developed and validated for estimation of drug in variety of newlinesamples like bulk, formulations, stability, in vitro and in vivo. Adequate newlinepreformulation studies were carried out using instruments like DSC and FT-IR to newlineunderstand the physicochemical nature and stability of drug in presence of different newlineexcipients under variety of conditions. This in turn helped in selection of appropriate newlineexcipients. newlineMucoadhesive buccal tablets of FDP with 5 mg loading were prepared by newlinedirect compression method. Formulations were designed using varying proportions of newlinevarious mucoadhesive and rate controlling polymers like hydroxyethyl cellulose newline(HEC), ethylcellulose (EC), hydroxypropyl methyl cellulose (HPMC), chitosan (CH), newlineguar gum (GM), agar (AR), polycarbophil (PC), carbopol (CP) and eudragit (EG). newlineThe designed buccal tablets were evaluated for the physical characteristics such as newlinedrug content, weight variation, friability, thickness and surface pH. In vitro drug newlinerelease studies were performed using in housed modified dissolution assembly and in newlinevitro mucoadhesion studies.