OPTIMIZATION OF THEOPHYLLINE SUSTAINED RELEASE TABLETS WITH A COMBINATION OF ETHYLCELLULOSE AND XANTHAN GUM MATRIX USING SIMPLEX LATTICE DESIGN METHOD

Objective: The study aims to investigate the effects of combining Ethyl Cellulose (EC) and Xanthan Gum (XG) matrix on the physical properties dissolution profiles and determine the optimal formula for sustained-release theophylline tablets. Methods: We used the Design Expert 13 software with the Simplex Lattice Design (SLD) models EC (A) and XG (B) to obtain the sustained release tablet formula of theophylline, which yielded seven formulas: F1 (80:120), F2 (110:90), F3 (120:80), F4 (90:110), F5 (100:100), F6 (120:180), and F7 (80:120). Granule evaluation included flowability rate, angle of repose, and compressibility index. Tablet evaluation included weight uniformity, hardness, friability, uniformity of content, and dissolution rate. Results: The physical properties of granules and tablets from the optimal formula showed that all test parameters met the standards. The granule flow rate was 11.98 g/sec, angle of repose 33.65, compressibility index 13.36%, tablet weight uniformity (%CV) 0.40%, tablet hardness 15.18, tablet friability 0.36%, content uniformity 98.03%, dissolution rate 11.30 mg/h. The effect of XG was more dominant in improving flow properties, angle of repose, compressibility index, weight uniformity, hardness, content uniformity, and dissolution rate. On the contrary, the more dominant EC could increase tablet friability and sustained drug release from the matrix. Conclusion: The optimal formula for theophylline sustained-release tablets contains a combination of EC: XG ingredients with a concentration of 107.03:92.97 mg, respectively, with a desirability value of 0.507.