Dissolution characteristics of megaloporous tablets prepared with two kinds of matrix granules.

The purpose of this study is to obtain a drug release at a constant rate with a megaloporous tablet, which was prepared with a simple formulation. These tablets were prepared with two kinds of granules. One of them is the restraining-phase matrix granule (RMG) and it controls the release rate of the drug. The other one is the soluble housing-phase matrix granule (HMG) and controls liquid penetration into the system. Eudragit RL 100 and Eudragit L 100 polymers were used to constitute the restraining and housing matrix phases, respectively. The effect of the amount of Eudragit RL 100 in the RMG was investigated and decreasing of amount of Eudragit RL 100 in the RMG increased the drug release rate. The tablets were prepared with compaction pressures of 188, 377, 1884 and 7540 kg/cm(2) and it was observed that the compaction forces ranging from 377 to 7540 kg/cm(2) did not influence drug release. The effect of the size of the matrices was demonstrated and it was found that the drug release rate increased with decreasing of the size of the tablets. The impact of the dosage to the dissolution rates was also investigated using two different amounts of drug. Therefore, the tablets were designed with two different dosages to use once or twice a day at the dosage interval of every 12 or 24 h, respectively. The release kinetic of the best formulation (4K) of the study was evaluated with the goodness-of-fit analysis and it was seen that the target profile was nearly achieved. This study suggests using megaloporous tablets in therapy, which could be prepared with a simple and cheap way similarly to conventional tablets to obtain a constant drug release.