Once Daily Sustained-Release Matrix Tablet of Naproxen: Formulation and In Vitro Evaluation

The objective of the present study was to develop once-daily sustained-release matrix tablets of naproxen, one of the most potent non-steroidal anti-inflammatory agents used in the treatment of arthritic pain. The tablets were prepared by direct compression method using hydrophilic matrix materials like Methocel K4M CR and Methocel K15M CR. The tablets were subjected to measurement of thickness, diameter, weight variation, drug content, hardness and friability, the results of which were within compendial specification range. In vitro release studies were carried out by the USP basket method and were carried out at pH 7.4 buffer for ten hours. The results of dissolution studies indicated that higher polymer content in the matrix (40%) decreased the release rate of the drug as shown in formulation NMK4MF6 and NMK15MF6 (where lactose content is zero). The most successful formulations of the study, exhibited satisfactory drug release which was very close to the theoretical release profile. All the formulations exhibited diffusion-dominated drug release.