Development of Mucoadhesive Patches for Buccal Administration of Carvedilol

A buccal patch for systemic administration of carvedilol in the oral cavity has been developed using two different mucoadhesive polymers. The formulations were tested for in vitro drug permeation studies, buccal absorption test, in vitro release studies, moisture absorption studies and in vitro bioadhesion studies. The physicochemical interactions between carvedilol and polymers were investigated by Fourier transform infrared (FTIR) Spectroscopy. According to FTIR the drug did not show any evidence of an interaction with the polymers used and was present in an unchanged state. XRD studies reveal that the drug is in crystalline state in the polymer matrix. The results indicate that suitable bioadhesive buccal patches with desired permeability could be prepared. Bioavailability studies in healthy pigs reveal that carvedilol has got good buccal absorption. The bioavailability of carvedilol from buccal patches has increased 2.29 folds when compared to that of oral solution. The formulation AC5 (HPMC E 15) shows 84.85 + 0.089% release and 38.69 + 6.61% permeated through porcine buccal membrane in 4 hr. The basic pharmacokinetic parameters like the C(max), T(max) and AUC(total) were calculated and showed statistically significant difference (P<0.05) when given by buccal route compared to that of oral solution.