Design and in vivo evaluation of carvedilol buccal mucoadhesive patches

The buccal region offers an attractive route of administration for systemic drug delivery. Carvedilol [dose, 3.125-25 mg] is beta-adrenergic antagonist. Its oral bioavailability is 25-35% because of first pass metabolism. Buccal absorption studies of a carvedilol solution in human volunteers showed 32.86% drug absorption. FTIR and UV spectroscopic methods revealed that there was no interaction between carvedilol and polymers. Carvedilol patches were prepared using HPMC, carbopol 934, eudragit RS 100, and ethylcellulose. The patches were evaluated for their thickness uniformity, folding endurance, weight uniformity, content uniformity, swelling behaviour, tensile strength, and surface pH. In vitro release studies were conducted for carvedilol-loaded patches in phosphate buffer [pH, 6.6] solution. Patches exhibited drug release in the range of 86.26 to 98.32% in 90 min. Data of in vitro release from patches were fit to different equations and kinetic models to explain release profiles. Kinetic models used were zero and first-order equations, Hixon-Crowell, Higuchi, and Korsmeyer-Peppas models. In vivo drug release studies in rabbits showed 90.85% of drug release from HPMC-carbopol patch while it was 74.63 to 88.02% within 90 min in human volunteers. Good correlation among in vitro release and in vivo release of carvedilol was observed

Extended Hansen's solubility approach: meloxicam in individual solvents

The solubility behaviour of meloxicam in individual solvents ranging from non-polar to highly polar was studied. For understanding the solute-solvent interactions, partial solubility parameters concept was utilized. The extended Hansen's method was used for analyzing the solubility data and for obtaining partial solubility parameters of meloxicam. The analysis was not successful though correlations were 81%. The Flory-Huggins size correction term [B] was found to improve the prediction of solubility. The correlations were high [92%] and total solubility parameter was 11.6 H. The four-parameter approach involving proton-donor and proton-acceptor parameters was also used in fitting the solubility data. The correlations were appreciable [87%] and total solubility parameter was 11.2 H. The term [B] combined with four-parameter approach was also used in order to improve the data, and was found to be improved the correlations [R[2] = 0.94]. This new approach may thus be used in fitting the experimental solubility data and to predict solubility behaviour of meloxicam in untested solvents. The total solubility parameter of meloxicam was assigned at 11.2 H