Simple Controlled Release Delivery System for an Anti-hypertensive Drug via Buccal Route

Objective: This study aims to develop controlled release buccal tablets of losartan potassium based on bioadhesion using direct compression technique. Materials and Methods: The bioadhesive buccal tablets of losartan potassium were prepared after preliminary drug-excipients compatibility studies and micromeretics study for powder blends. The tablets were prepared by direct compression utilizing carbopol 934LR as a primary bioadhesive polymer either with or without chitosan or hydroxypropyl methylcellulose E15LV as secondary polymers. Other excipients included PVP K30 as a binder, magnesium stearate as a lubricant and mannitol as a diluent. The tablets were evaluated for weight variation, thickness and diameter, hardness, friability, drug content, surface pH, Ex-vivo residence time and bioadhesion force, In-vitro swelling and drug release study. The analysis of the release profiles in the light of distinct kinetic models (zero order, first order, Higuchi, Hixson-Crowell and Korsmeyer–Peppas) was carried out. Results and Discussion: The formula containing 40% w/w bioadhesive polymers of carbopol 934LR and chitosan (1:2) was selected as the optimum one based on a ranking methodology and then, it was subjected to Ex-vivo permeation and physical stability study in human saliva. Swelling index was 78.32±1.84% after 7h and tablets showed a neutral surface pH. Ex-vivo residence time was long enough for more than 10h. Ex-vivo bioadhesion force was 0.38±0.01N. Drug release was 57.64±3.43% after 8h following zero order kinetics with a steady state permeation flux of 0.959mg/cm2h. Tablets were physically stable in human saliva. Conclusion: These formulae improved, controlled and prolonged the release of losartan potassium from a buccal bioadhesive system for at least 8h in a simple way which can achieve a high patient compliance.