Development and characterization of a carvedilol-loaded self-microemulsifying delivery system

The objective of the work was to develop, optimize, and evaluate a self-microemulsifying drug delivery system of the poorly water-soluble drug, carvedilol. Solubility of carvedilol was determined in various vehicles. Ternary and pseudo-ternary phase diagrams were constructed to indentify the efficient self-emulsification region using oils, surfactants, and co-surfactants in aqueous environment. Optimized formulations were assessed for drug content, spectroscopic clarity, emulsification time, contact angle, zeta potential, particle size, and dissolution studies. Zeta potential was measured in the absence and presence of oleylamine, a positive charge inducer. On the basis of similarity and dissimilarity of particle size distribution, formulations were characterized using PCA and AHCA, a multivariate statistical analysis. Decrease in t50% and increase in DE attributed to small globule size and eventually higher surface area. The relevance of differences in t50% and DE was evaluated statistically by two-way ANOVA. DRIFTS, DSC, and X-RD studies indicated no incompatibility between drug, oil, and surfactants. The results of this study indicate that the SMEDD formulations of carvedilol owing to nanosize have the potential to enhance its absorption, without interaction or incompatibility between the ingredients.