Formulation and evaluation of buccal bioadhesive tablets using glimepiride as a model drug

Objectives: The present investigation is concerned with formulation and evaluation of bioadhesive buccal tabletscontaining antidiabetic drug, Glimepiride to circumvent the first pass effect and to improve its bioavailability because bioadhesion has shown renewed interest for prolonging the residence time of bioadhesive dosage forms through various mucosal routes in drug delivery applications. Bioadhesive-based topical and local systems have shown enhanced bioavailability. Bioadhesive drug delivery gives rapid absorption and good bioavailability due to itsconsiderable surface area and high blood flow. Drug delivery across the mucosa bypasses the first-pass hepaticmetabolism and avoiding the degradation of gastrointestinal enzymes and with reduction in dosing frequency and dose related side effects. Methods: The tablets were prepared by direct compression method. Six formulations weredeveloped with varying concentrations of polymers like sodium alginate, PVP and magnesium stearate. The tabletswere tested for weight variation, hardness, surface pH, drug content uniformity, percentage swelling index,bioadhesive strength, ex-vivo residence time in-vitro drug dissolution study, in-vitro drug release kinetic study, exvivo permeation study and Stability study. Results: FTIR studies showed no evidence on interactions between drug, polymers, and excipients. The surface pH, bioadhesive strength was found to be 6.22, 16g and, respectively. The formulation containing 4 mg of Glimepiride exhibited 6 h sustained drug release i.e. 93.98±0.8% with desiredtherapeutic concentration. The drug permeation from the formulation was slow and steady and 3.56 mg of Glimepiride could permeate through sheep buccal membrane with a flux of 0.27 mg hr-1 cm-2. The in-vitro release kinetics studies reveal that the formulation fits well with zero order kinetics. Conclusion: Hence, it was concluded that the formulation was suitable for all the evaluation parameters and can be permeated through human buccal mucosa.