Design and evaluation of sustained release hydrophilic matrix tablets of Piroxicam based on carboxymethyl xanthan derivatives

The objective of this study was to formulate hydrophilic matrices for a controlled delivery of Piroxicam using carboxymethyl xanthan gum derivatives (CMX). CMXs with various degrees of substitution (DS = 0.22, 1.70 and 2.85) were synthesized by an etherification reaction, and their characterization was realized by FT-IR spectroscopy, X-ray diffraction, and scanning electron microscopy. Different tablets were prepared using the direct compression method. The powder mixtures were characterized by the determination of their angle of repose, compressibility index and Hausner ratio, whereas weight uniformity, hardness, friability, drug content, and in-vitro drug dissolution were employed to test the tablets under simulated gastric and intestinal conditions. The obtained results indicated that the drug release rate increases with the CMX ratio. The matrices based on CMX2 (DS = 1.7) were found to be the best candidates in controlling the release profile, where the optimal formulation contains 40% of CMX2 (F9). The dissolution data showed that all matrices fit well with Korsmeyer-Peppas model, whereas the release kinetics of F9 followed non-Fickian type release. The highest mean dissolution time value was obtained for F9. Finally, these results revealed that CMXs are suitable excipients for the sustained release dosage forms for as long as 20 h.