Studies on Bio-adhesion of Matrix Tablets: II.Comparison on Bio-adhesion Strength and Release Profiles of Theophylline Anhydrous and Its Sodium Glycinate Salt

Abstract

Controlled release matrix tablets of Theophylline anhydrous and Theophylline sodium glycinate were prepared with different types of bio-adhesive polymers e.g. HPMC 15 & 50 cps, Gelatin, PVP K-30, Na-CMC and Xanthan gum. Tablets, prepared by direct compression method were subjected to in-vitro drug dissolution for 8 hours in 0.1 N hydrochloric acid (pH 1.2) using a thermal shaker at 50 rpm at 37 ± 0.5ºC. The bio-adhesive property was investigated in terms of retention time following in-vitro wash-off method by Lehr et al. The anhydrous and corresponding salt form was used to investigate whether physical variation of Theophylline molecule can cause any change in release and bio-adhesion property or not. In most of the cases it is found that salt form releases greater percentage of active drug than its corresponding anhydrous form. Irrespective of drug’s physical property and amount of polymer, bio-adhesive strength of Xanthan gum was proved to be maximum followed by HPMC- 50 cps, Na-CMC and HPMC- 15 cps, whereas gelatin and PVP K-30 showed little or poor muco-adhesion. Xanthan gum, Na-CMC and HPMC based formulations showed nearly zero-order release; on the contrary PVP K-30 based formulation showed a burst release within one hour of dissolution.DOI: http://dx.doi.org/10.3329/dujps.v10i1.10008DUJPS 2011; 10(1): 1-7