In vitro-in vivo correlation study on nimesulide loaded hydroxypropylmethylcellulose microparticles / 药学学报

This study involves mathematical simulation model such as in vitro-in vivo correlation (IVIVC) development for various extended release formulations of nimesulide loaded hydroxypropylmethylcellulose (HPMC) microparticles (M1, M2 and M3 containing 1, 2, and 3 g HPMC, respectively and 1 g drug in each) having variable release characteristics. In vitro dissolution data of these formulations were correlated to their relevant in vivo absorption profiles followed by predictability worth analysis of these Level A IVIVC. Nimaran was used as control formulation to validate developed formulations and their respective models. The regression coefficients of IVIVC plots for M1, M2, M3 and Nimaran were 0.834 9, 0.831 2, 0.927 2 and 0.898 1, respectively. The internal prediction error for all formulations was within limits, i.e., < 10%. A good IVIVC was found for controlled release nimesulide loaded HPMC floating M3 microparticles. In other words, this mathematical simulation model is best fit for biowaiver studies which involves study parameters as those adopted for M3 because the value of its IVIVC regression coefficient is the closest to 1 as compared to M1 and M2.

comparative study of various microencapsulation techniques: effect of polymer viscosity on microcapsule characteristics

It is a comparative study of salbutamol sulpahte-ethylcellulose microcapsules prepared by three different microencapsulation techniques i.e. coacervation thermal change, solvent evaporation and coacervation nonsolvent addition by adjusting the ratio of salbutamol sulpahte to ethylcellulose. In vitro release profiles of microcapsules were studied using USP XXIV dissolution apparatus-I in 450 ml double distilled water maintained at 37°C at 50 rpm. Scanning electron microscopic results indicated that all microcapsules were aggregated, whitish and irregular in shape with good entrapment efficiency [86.34 to 97.83], production yield [87.91 +/- 1.34 to 98.33 +/- 1.37] and flow properties. Initial burst effect was observed in the drug release behavior from all microcapsules. A slight increase in actual drug loading but profound increase in mean diameter of microcapsules was observed with the increase in the viscosity of ethylcellulose. UV and FTIR spectroscopy, x-ray diffractometry and thermal analysis verified the absence of any strong chemical interaction between drugs and polymer. The drug release from all the formulations followed anomalous diffusion mechanism and was best fit to Higuchi's kinetic model. The results suggest coacervation thermal change as an appropriate approach to develop slow-release multi-unit oral dosage form of salbutamol sulpahte suggesting at least twice administration in every 24 hours