Pharmacokinetic evaluation of guar gum-based three-layer matrix tablets for oral controlled delivery of highly soluble metoprolol tartrate as a model drug

The objective of the present study is to carry out pharmacokinetic evaluation of oral controlled release formulation (guar gum-based three-layer matrix tablets) containing highly soluble metoprolol tartrate as a model drug. Six healthy volunteers participated in the study, and a two-way crossover design was followed. The plasma concentration of metoprolol tartrate was estimated by reverse-phase HPLC. The pharmacokinetic parameters were calculated from the plasma concentration of metoprolol tartrate versus time data. The delayed T-max, lower C-max decreased K-a, unaltered bioavailability and prolonged t(1/2) indicated a slow and prolonged release of metoprolot tartrate from guar gum three-layer matrix tablets in comparison with the immediate release tablet dosage form. The results of the study indicated that guar gum three-layer matrix tablets were able to provide oral controlled delivery of highly water-soluble drug such as metoprolol tartrate in humans. (C) 2004 Elsevier B.V. All rights reserved.