Formulation and Evaluation of Mucoadhesive Buccal Tablets of Repaglinide Using Primary Polymers: Carbopol 934P and HPMC K4M

The present study focuses on the formulation and evaluation of mucoadhesive buccal tablets of Repaglinide using Carbopol 934P and HPMC K4M as primary polymers to enhance bioavailability by circumventing first-pass metabolism. Tablets were prepared via direct compression, with or without the inclusion of secondary polymers such as Chitosan and Sodium Alginate. Drug estimation was carried out spectrophotometrically at 237 nm. Formulated tablets were evaluated for hardness, thickness, weight variation, friability, drug content, surface pH, swelling index, mucoadhesive strength, and in-vitro drug release. FTIR studies confirmed no significant drug–excipient interactions. Stability studies conducted at 40 ± 2 °C / 75 ± 5% RH for 3 months validated the physical and chemical stability of the formulations. Among the tested batches, CP1 (30% Carbopol 934P) and HP1 (30% HPMC K4M) exhibited optimal performance with drug release of 95.36% and 99.00% over 8 hours, and mucoadhesive strengths of 5.1 g and 4.0 g, respectively. Surface pH (6.6–6.9) remained within the acceptable mucosal range, indicating minimal irritation. The results support the suitability of Carbopol 934P and HPMC K4M as effective primary polymers for developing stable and efficient mucoadhesive buccal delivery systems of Repaglinide.