Curcumin (cur) elicits a wide spectrum of potent responses for local treatment of oral disorders. However, its clinical use in the oral cavity is limited by its poor solubility and chemical instability at salivary pH. This study aims to develop cur mucoadhesive buccal tablet formulation with enhanced cur solubility and stability. For this purpose, a rapidly dissolving solid dispersion (SD) was developed using PVP (Kollidon®25). In addition, chemical stability in phosphate buffer saline (PBS) pH 6.8 was investigated for the first time using different stabilizers to ensure cur stability for in-vitro and in-vivo studies. After addressing solubility and stability challenges, buccal tablets formulations were developed using Hydroxypropyl methylcellulose (HPMC) and Carboxymethyl cellulose (CMC sodium) mixture in different ratios with or without SLS as stabilizer.
Tablets containing HPMC.K15M: CMC sodium (5:1), SD (1:3), and 15 mg SLS showed the best results regarding mucoadhesive strength, in-vivo residence time, and release rate profile and were considered as the optimized formulation. The optimized formulation ensured cur stability as well as a controlled release rate, with considerable cur levels in saliva for over 12h. Preliminary clinical evaluation showed remarkable anti-inflammatory and healing effects in patients with aphthous ulcer, concluding that cur stabilized mucoadhesive formulation can efficiently treat various inflammatory oral diseases.