Akademik Veri Yönetim Sistemi
Turkish Journal of Pharmaceutical Sciences, cilt.7, sa.3, ss.225-236, 2010 (SCI-Expanded)
In this study, the effects of stirring rates (8000, 9500, 13500 rpm) and drug:Polymer ratios (1:25, 4:25, 6:25) on the pharmaceutical characteristics of Levobunolol HCl-loaded poly (s-caprolactone) microparticles in order to optimize formulations for ocular delivery were examined. Microparticles were prepared using multiple emulsion (W/O/W) solvent evaporation technique. Microparticles were characterized in terms of surface morphology, drug loading efficiency, production yield, particle size and size distribution, drug release, zeta potential and residual solvent. The physical state of microparticles was also determined by scanning electron microscopy (SEM). Spherical, smoother particles were obtained with a drug:polymer ratio of 6:25 at 8000 rpm. Drug:polymer ratio played greater role on drug loading efficiency than stirring rate. An increase in the stirring rate from 8000 to 9500 rpm resulted a decrease in particle size at all drug:polymer ratios. The fasted drug release and the highest drug-loading efficiency obtained from formulation of A10 prepared with 1:25 drug:polymer ratio at the stirring rate of 8000 rpm. Drug release was mainly fitted to the Higuchi model. The findings showed that both stirring rates and drug:polymer ratios had an effect on the pharmaceutical properties of microparticles.