Controlled release metformin hydrochloride microspheres of ethyl cellulose prepared by different methods and study on the polymer affected parameters

Abstract

The objectives of this investigation were to prepare microspheres of the anti-diabetic drug, metformin hydrochloride, using ethyl cellulose as the polymer and evaluate the encapsulation efficiency and release characteristics in vitro and in vivo; utilizing different microencapsulation techniques. Different proportions of polymer were used to obtain varying drug-polymer ratios. Physical properties, loading efficiency and dissolution rate were dependent on the method chosen for preparation and also on the drug-to-polymer ratio. The addition of surfactant during emulsification and petroleum ether in non-solvent addition process affected release of drug and also size distribution of microspheres. To investigate the type of mechanism that occurs, dissolution data were plotted according to different kinetic models. In vitro release studies show first order and Higuchi model release characteristics being exhibited. All the results were treated statistically to validate the findings. Significant differences in percentage yield, entrapment efficiency and sustaining capacity were seen with microspheres prepared by two different methods. In vivo studies in normal and hyperglycemic mice show faster glucose reduction with microspheres prepared by the evaporation method, whereas the release sustaining effect was more pronounced with microspheres prepared by the non-solvent addition method.

Fabrication and Development of Pectin Microsphere of Metformin Hydrochloride

“…Metformin HCl (MFH) is indicated for patients with noninsulin-dependent diabetes mellitus (NIDDM), particularly those with refractory obesity [5]. …”

Experimental design to predict process variables in the preparation of cellulose based sustained release microspheres system loaded with prednisolone-cyclodextrin complex

“…Since, ethyl cellulose is less permeable to water and this feature makes it relatively viscous. Polymer matrix with increasing fraction of ethyl cellulose when coming in contact with water becomes relatively impermeable to dissolution medium, and this event causes slower diffusion of drug [34,35]. The incomplete liberation of drug from the microspheres is observed because the polymers are not in disintegrated/degraded state [19].…”

Cellulose Polymers in Microencapsulation of Food Additives

“…Careful manipulation of EC solubility properties in various solvents has been used to develop coacervation coating systems. In particular, non solvent addition, emulsion-solvent evaporation, and temperature reduction-poor solvent methods have been employed to achieve very effective EC coatings in microencapsulation systems (Nixon, 1985;Chemtob et al, 1986;Nixon and Wong, 1990;Sveinsson and Kristmundsdottir, 1992;Amperiadou and Georgarakis, 1995;Jones and Pearce, 1995;Song et al, 2005;Choudhury and Kar, 2009). Select examples of these coating methods will be indicated described in Section 17.3.…”