Abstract

Formulation and Optimization of Candesartan Loaded Eudragit Coated Microspheres

Amit Sharma^*1, Swati Dikshit¹, Niraj Upamanyu¹, Subhendu S. Mishra², Ashish Pathak²

1. Department of Pharmaceutics, R.K.D.F College of Pharmacy, Bhopal, M.P., India.

ABSTRACT

The objective of present study is enhancement in the oral bioavailability of Candesartan using a lipid-based formulation i.e Eudragit S-100 microspheres. Candesartan is therapeutically a potent antihypertensive agent but it suffers a major drawback of poor oral bioavailability, which is estimated to be 15% due to low solubility in gastrointestinal fluid, hepatic first pass metabolism. The main emphasis of present study is on the use of new approach of lipid-based formulation to enhance the bioavailability of poorly water-soluble but highly permeable drug. The proposed formulation is aimed to enhance the bioavailability of Candesartan by using microspheres coated with eudragit S-100 polymer, which are transported through lymphatic system, thereby preventing hepatic first pass metabolism. Eudragit based microspheres were prepared by oil-in-oil solvent evaporation method using different drug- polymer ratios (1:1 to 1:4), stirring speeds (500-1500 rpm) and emulsifier concentrations (0.5%-1.25% wt/vol). Differential scanning calorimetry, study of the physical mixtures of drug and polymer revealed no drug-polymer interaction. All formulations were evaluated for particle size and shape, swell ability and percentage drug entrapment. The yield of preparation and the encapsulation efficiencies were high for all Eudragit microspheres. The in vitro drug release study of optimized formulation was also performed in simulated gastrointestinal fluids (SGF). The release profile of Candesartan from Eudragit microspheres was pH dependent.

Keywords: Eudragit S 100, Colon specific drug delivery, Microspheres, Candesartan.