Carvedilol-loaded mucoadhesive buccal tablets: influence of various mucoadhesive polymers on drug release behavior.

The major objectives of the current study were (i) to prepare carvedilol-loaded buccal tablets by direct compression technique, and (ii) to study the influence of low and high proportions of sodium carboxy methylcellulose (SCMC) in conjunction with the corresponding high and low proportions of sodium alginate, polyvinyl pyrrolidone (PVP-K-30), carbopol 974P, and hydroxypropyl methylcellulose (HPMC) on the basic properties (hardness, friability, weight variation, thickness uniformity, drug content, mucoadhesive strength, surface pH, swelling property, and drug release behavior) of the tablets. Altering the polymer combinations did not affect the physical properties of the buccal tablets. However, the presence of SCMC and sodium alginate at 1:2 ratio in the tablet showed a sustained drug release. In addition, this polymer combination at 2:1 ratio did release the drug completely during the stipulated dissolution time. Swelling study indicated the tablet structure collapse over time at 2:1 polymer ratio, thus exposing the drug molecules directly to the dissolution medium to attain the complete drug release from the SCMC and sodium alginate-based tablets. On the other hand, whatever the polymer ratios, the SCMC and carbopol 974P combination always retarded the drug release in an almost similar manner. Though the SCMC- and carbopol 974P-based tablets did display an impressive mucoadhesion property, the surface pH value determined for this polymer combination was found to decrease considerably due to the liberation of the free carboxylic acid over the time period.