FORMULATION AND EVALUATION OF CLARITHROMYCIN POORLY SOLUBLE DRUG AS MICROEMULSION

Abstract

Clarithromycin is well absorbed from the gastro intestinal tract, but its systemic bioavailability is 55% due to first pass metabolism. It undergoes rapid biodegradation to produce the microbiologically active 14-hydroxy metabolite. The design of the novel o/w microemulsion formulation, which enhances the oral bioavailability by raising the solubility of poorly water soluble clarithromycin was studied. Microemulsion were prepared by using oil phase (ethyl oleate and olive oil), diglyceryl monooleate (DGMO-C) lipophilic surfactant, polyoxyethylene 40 hydrogenated castor oil   (HCO-40) hydrophilic surfactant, ethanol (co-surfactant), phosphate buffer solution (PBS) pH 6.8 as a aqueous phase and clarithromycin. Prepared formulations were evaluated for size, viscosity, zeta potential, drug content, in vitro release studies & in vivo studies. Average particle size of clarithromycin o/w microemulsion for F1 and F2 was 350-450 nm and 800-900 nm. Results of viscosity, exhibited a simple newtonian flow. Zeta potential of F1 indicates plateau of stability and no agglomerates & F2 o/w microemulsions which indicates plateau of slight stability and few agglomerates. Drug content of the F1 was more than F2 this may be because of increased solubility of drug in the oil (ethyl oleate). The release profile revealed that formulations F1 followed peppas model and F2 higuchi matrix model. The plasma concentration was more in formulation (F1) 47.03 mg /mL then (F2) 31.10 mg /mL. Hence F1 o/w microemulsion can be a useful formulation, which enhances the oral bioavailability by increasing the solubility of poorly water soluble drug clarithromycin.