Preparation and characterization of self-microemulsifying drug delivery system of carvedilol

Carvedilol is a non-selective beta blocker and belongs to the third generation of beta blockers antihypertensive agent which is administered orally that has absolute bioavailability of only 25% to 35% due to the poor aqueous solubility (0.583 mg/L & log P 4.115). The aim of the present investigation was to develop a self-microemulsifying drug delivery system (SMEDDS) to enhance the oral absorption of Carvedilol. The solubility of Carvedilol in various oils, surfactants, and cosurfactants was determined. Pseudoternary phase diagrams was plotted to identify the efficient self-emulsification regions using Oleic acid, Tween 80, PEG-400 to identify the efficient self-micro emulsification region. Prepared SMEDDS was further evaluated for its visual assessment and emulsification time, effect of pH, robustness, dispersibility, transmittance test, cloud point measurement, optical clarity, drug content and in vitro dissolution study. All the prepared formulation exhibited self-emulsification properties. The optimized formulation F3 contains Carvedilol (6.25 mg), Oleic acid (20%), Tween 80(68.5%) and PEG-400 (11.4%). From the study, it was concluded that formulation F3 has good emulsification property with uniform globule size, satisfactory in vitro drug diffusion profile which identify future opportunities for Carvedilol delivery.