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BioMed Research International
Volume 2013 (2013), Article ID 716736, 9 pages
Research Article

Formulation Development and Stability Studies of Norfloxacin Extended-Release Matrix Tablets

1Post Graduation Program in Pharmaceutical Sciences, Universidade Estadual do Centro Oeste (UNICENTRO), 85040-080 Guarapuava, PR, Brazil
2Post Graduation Program in Pharmacy, Health Science Centre, Federal University of Santa Catarina, Quality Control Laboratory, J/K 207, 88040-900 Florianópolis, SC, Brazil
3Laboratory of Quality Control and Pharmaceutical Analysis, Faculty of Pharmacy, Federal University of Rio de Janeiro, 27930-560 Macaé, RJ, Brazil

Received 25 April 2013; Revised 25 July 2013; Accepted 31 July 2013

Academic Editor: Fabio Sonvico

Copyright © 2013 Paulo Renato Oliveira 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.


The aim of this research was to develop a new hydrophilic matrix system containing norfloxacin (NFX). Extended-release tablets are usually intended for once-a-day administration with benefits to the patient and lower discontinuation of the therapy. Formulations were developed with hydroxypropylmethylcellulose or poly(ethylene oxide) as hydrophilic polymers, with different molecular weights (MWs) and concentrations (20 and 30%). The tablets were found to be stable (6 months at °C and % relative humidity), and the film-coating process is recommended to avoid NFX photodegradation. The dissolution profiles demonstrated an extended-release of NFX for all developed formulations. Dissolution curves analyzed using the Korsmeyer exponential equation showed that drug release was controlled by both drug diffusion and polymer relaxation or erosion mechanisms. A more erosion controlled system was obtained for the formulations containing lower MW and amount of polymer. With the increase in both MW and amount of polymer in the formulation, the gel layer became stronger, and the dissolution was more drug-diffusion dependent. Formulations containing intermediate MW polymers or high concentration (30%) of low MW polymers demonstrated a combination of extended and complete in vitro drug release. This way, these formulations could provide an increased bioavailability in vivo.