Table of Contents
ISRN Pharmaceutics
Volume 2013, Article ID 719196, 15 pages
Research Article

Statistical Optimization and In Vitro Evaluation of Metformin Hydrochloride Asymmetric Membrane Capsules Prepared by a Novel Semiautomatic Manufacturing Approach

1Department of Pharmaceutics, M. S. Ramaiah College of Pharmacy, M. S. R. Nagar, MSRIT Post, Bangalore 560 054, India
2Department of Pharmacognosy, M. S. Ramaiah College of Pharmacy, Bangalore 560 054, India

Received 12 September 2013; Accepted 21 October 2013

Academic Editors: C. Ferrero Rodríguez, K. Goracinova, and T. Pongjanyakul

Copyright © 2013 Venkatesh Teja Banala et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Asymmetric membrane capsules (AMCs) are one of the novel osmotic delivery devices which deliver a wide range of drugs in controlled manner. In the present work, we developed and validated a semiautomatic process by fabricating a hydraulic assisted bench top model for manufacturing AMCs. The capsule walls of AMCs were prepared by dip coating phase inversion process using cellulose acetate butyrate (CAB) as coating polymer and propylene glycol (PG) as plasticizer and pore former. The comparative examination of physical parameters confirmed the consistency, efficiency, and reproducibility of the semiautomatic process over the manual procedure. The SEM studies revealed a thin dense region supported on a thicker porous membrane of the capsule shells. Formulations of AMCs were prepared based on a 23 full factorial design using metformin hydrochloride as the model drug. The effect of formulation variables such as concentration of PG and levels of fructose and potassium chloride were studied on the in vitro drug release using Design-Expert 8.0.2 (USA) software. From the in vitro release studies, it was observed that the concentration of pore former and level of osmogents had a direct effect on the drug release. From the validation studies of the optimized formulation (OPT) with the predicted response, it was observed that the drug release was independent of pH and agitation intensity but dependent on osmotic pressure of the dissolution medium. The OPT followed controlled zero-order release kinetics over a period of 13 h.