Abstract

DESIGN FORMULATION AND EVALUATION OF FLOATING MICROSPHERES OF TIMOLOL

Ch. Taraka Ramarao* and T. Yugandhar

ABSTRACT

The goal of present investigation attempt was made to prepare microspheres of timolol employing by using various polymers like HPMC K15M, Eudragit S100 and ethyl cellulose to achieve an oral controlled release of the timolol. In the present study nine formulations were formulated by using HPMC K15M, Eudragit S100 and EC in various proportions (1:1, 1:2, 1:3). All the formulations were subjected to (%) Percentage yield, drug content, buoyancy time and entrapment efficiency, in vitro dissolution and release kinetics shown satisfactory results. Entrapment efficiency was increased with increased polymer concentration. On the basis of release data and graphical analysis formulation F6 shown good controlled release profile with maximum entrapment efficiency because of high polymer concentration. The co-efficient of determination indicated that the release data was best fitted with zero order kinetics. Higuchi equation explains the diffusion controlled release mechanism. The diffusion exponent ‘n’ values of Korsemeyer- Peppas model was found to be in the range of more than 1 for the Timolol floating microspheres prepared with drug and Eudragit indicating super case II transport diffusion mechanism of drug through timolol floating microspheres. The floating microsphere is possible to formulate promising controlled release timolol. The results it can be concluded that the drug release from the floating microspheres diffusion controlled. The formulations showed best appropriate balance between buoyancy and in vitro drug release. The floating microspheres are stable during shelf life.

Keywords: Micro spheres; HPMC K 15M; Buoyancy; Entrapment efficiency; Percentage yield.