Formulation and in vitro in vivo evaluation of buccal bioadhesive captopril tablets

The objectives of this study were to elucidate factors affecting the bioadh esion property of compressed tablets consisting of hydroxypropylmethyl cell ulose and carbomer and to evaluate the bioavailability and pharmacokinetics of the formulated buccal adhesive captopril tablets. Buccal adhesive contr olled-release systems for the delivery of captopril were prepared by compre ssion of hydroxypropylmethyl cellulose with carbomer, which served as the b ioactive adhesive compound. The interpolymer complex formation between hydr oxypropylmethyl cellulose and carbomer was characterized in an acidic mediu m by turbidity, viscosity and FT-IR measurements. The kinetics of buccal ad hesive and conventional tablets (Kapril) of captopril were examined in eigh t healthy volunteers. A single dose of captopril (50 mg) was administered a s buccal adhesive and commerically available conventional (Kapril) tablets on two different occasions in a randomized crossover fashion. The release b ehaviour of the systems containing 50 mg of captopril and two polymers at d ifferent ratios was found to be non-Fickian. The mean pharmacokinetic param eters after buccal adhesive tablet ml, and after conventional tablet admini stration were: C-max, 310.7 ng/ml; t(max), 1.2 h; AUC(0-8), 890.1 ng.h/ml. This study demonstrated that the formulated buccoadhesive therapeutic syste m is suitable for buccal administration of captopril.