Evaluation of Matrix Tablets Based on Eudragit®E100/Carbopol®971P Combinations for Controlled Release and Improved Compaction Properties of Water Soluble Model Drug Paracetamol

The purpose of this work was to investigate the influence of Eudragit (R) E100 polymer in modifying the release rates and compaction properties of water soluble model drug paracetamol from Carbopol (R) 971P NF polymer matrix tablets prepared by direct compression. The effects of the ratio of the two polymers, the total polymeric content, and the tablets mechanical strength on paracetamol release rates were investigated. Dissolution studies were conducted using USP XX Pi rotating paddle apparatus at 50 rpm and 37 degrees C at three different stages (pH 1.2, 4.8, and 6.8). Results showed that the polymers combination improved significantly the compaction properties of paracetamol tablets as evident by the higher crushing strengths (8.3 +/- 0.4 Kp) compared to polymer-free tablets (3.4 +/- 0.2 Kp) at intermediate compression pressure of 490 MPa. When combined with Carbopol (R) 971P NF, Eudragit (R) E100 was found to be capable of extending paracetamol release for more than 12 h compared to 1 h for polymers-free tablets. The combined polymers were able to control paracetamol release in a pH independent pattern. The f2 (similarity factor) analysis showed that the ratio between the polymers and the total polymer concentration exhibited significant impact on drug release rates. In conclusion, Eudragit (R) E100 when combined with Carbopol (R) 971P NF was capable of improving the compaction and sustained release properties of paracetamol. Korsmeyer-Peppas model was found to be the most suitable for fitting drug release data. The polymer combinations can potentially be used to control the release rates of highly water soluble drugs.