In vitro and in vivo assessment of Adansonia digitata mucilage as a matrix former in modified release tablets of metoprolol tartrate

Abstract

The study was aimed to investigate the ability of Adansonia digitata mucilage (ADM) a new hydrophilic plant polymeric material, in modifying metoprolol tartrate (MPT) release from matrix tablet formulations in comparison with a semi -synthetic polymer-HPMC60SH 4000. Modified release tablets of MPT were directly compressed in the ratios of 1:1 and 1:4 drug/polymer amounts. The tablets properties were evaluated and further, in vivo studies were carried out on 1:4 drug/polymer matrix tablets formulated with ADM and compared with Slow- Lopressor Divitab®. In vitro drug release of MPT was controlled over 24 h for tablets with 1:4 drug/polymer ratios. Release profiles of formulations showed pH independent release and no burst effect at high drug loading. Matrix integrity was maintained throughout dissolution with ADM matrices, an indication of good gel strength contrary to HPMC matrices. Statistical analysis confirmed that MPT release from ADM and HPMC (1:4 drug/polymer) was not significantly different (P > 0.05) likewise similarity factor (f2). The in vivo bioavailability after oral administration of the test formulation (1:4 MPT/ADM) to dogs did not differ significantly from the reference marketed sustained release product.