Functionality of Benecel K4M/Carbopol 971P NF matrices in direct compression tablets for controlled release

The aim of this work is the assessment of the eventual enhancing effects of Carbopol 971P NF on the performance of Benecel K4M as a controlled release agent and its impact on other technological properties such as compactibility and powder flowability. The effect of Carbopol 971P NF and Benecel K4M in the performance of metronidazole tablets with controlled release was assessed using dissolution and compactibility profiles and the flowability of powders. Benecel K4M produces release profiles with an average exponent n=0.711 while Carbopol 971P NF displays average values of n=1.19. The values for tablets containing equal parts of Carbopol 971P NF and Benecel K4M was an average of n=0.947. Metronidazole tablets containing the Benecel K4M/Carbopol 971P NF blend shows a compactibility 2-3 times higher than tablets containing only Benecel K4M. Metronidazole/Benecel K4M blends flow sufficiently at all studied polymer proportions (≤ 30%) while admixtures of metronidazole/Benecel K4M with Carbopol 971P NF flow sufficiently only at polymer proportions ≤ 17%. Carbopol 971P NF enhances the overall performance of Benecel K4M in the same way as Noveon AA1 does, it reduces better the drug release and improves the compactibility, although decreases the flowability.