Extended Release of Metoprolol Succinate from HPMC Reinforced Alginate Microparticle
 Rabinarayan PARHI*^,°, Padilam SURESH*
 * GITAM Institute of Pharmacy, GITAM University, Gandhi Nagar Campus, Rushikunda, Visakhapatnam-530045, Andhra Pradesh, India

 ° Corresponding Author E-mail: bhu_rabi@rediffmail.com

Summary

The aim of the present investigation was to prepare and characterize hydroxypropyl methylcellulose K100LV (HPMC K100LV) reinforced sodium alginate microparticles of Metoprolol succinate (MS) in order to reduce burst release and extend the drug release. Microparticles were prepared by w/o-emulsification external gelation technique. The microparticles were characterized by X-ray analysis, FT-IR study, particle size and scanning electron microscopy (SEM). The in vitro drug release was carried out in phosphate buffer pH 6.8 as dissolution medium for 8 h. Irregular surface texture with particle size less than 7μm were obtained from SEM and particle size analysis. FT-IR spectra gave evidence of interaction between N-H group of MS and C = O group of alginate. MS was dispersed in the molecular form in the polymer matrix as indicated by X-ray diffraction pattern. More than 87% drug release was found in all the batches after 8 hr of dissolution study. Burst release was evident (65.08% drug release in 1 hr) in microparticles (MP1) with only alginate. A significant reduction in the burst effect and extended drug release were observed as the concentration of HPMC increased. Release rate exponent (n) values were less than 0.43, indicating Fickian diffusion could be the mechanism of drug release.

Key Words :
Extended release, Metoprolol succinate, Burst release, Hydroxypropyl methylcellulose, Alginate.