Design and Evaluation of Modified Release Bilayer Tablets of Flurbiprofen

Objectives. To design and evaluate modified release bilayer tablets of flurbiprofen. Material and Methods. In this study, bilayer modified release (MR) tablets of flurbiprofen were formulated using ethyl cellulose (EC) and polyvinylpyrrolidone (PVP) in different ratios as release retardant materials using a wet granulation method. In vitro release studies were done in dissolution media of varying pH i.e. pH 1.2, 4.5, 7.0 and 7.5. Results. All tablets exhibited good physical quality with respect to appearance, content uniformity, hardness, weight variation and friability. In vitro dissolution data showed that increasing proportions of EC retarded whereas increasing PVP enhanced the drug release rate. The bilayer MR tablets showed an initial release of approximately 35% (i.e. 100 mg drug) in about 1 h, then sustaining the release for 12 h, ending up with 89.56% and 96.12% for formulation MR1 and MR2, respectively. The kinetic analysis of dissolution data showed that zero order release was observed in these tablets. When data was fitted to the Korsmeyer-Peppas model, a non-Fickian transport was observed with the MR tablets. A model independent approach showed that as the release rate increases, the MDT decreases, showing the retarding behavior of the non-biodegradable polymers employed in formulation development. Conclusions. Bilayer modified release tablets of flurbiprofen can be successfully formulated using ethylcellulose and polyvinylpyrrolidone in different ratios as release retardant materials employing a wet granulation method (Adv Clin Exp Med 2011, 20, 3, 343–349).