Hydroxyethyl Pachyman as a novel excipient for sustained-release matrix tablets

• The hydroxyethyl pachyman (HEP) Tablets were prepared successfully.
• The HEP tablets formed highly porous gel network structure in dissolution solution.
• The tablets containing HEP matrix showed sustained drug release.
• Diclofenac Sodium showed a pH sensitive release from HEP tablets.

This paper addressed the application of hydroxyethyl pachyman (HEP) as a novel matrix for sustained – release tablets, using diclofenac sodium (DS) as a model drug. The studies showed the HEP tablets prepared by wet granulation had much slower drug release as compared to those prepared by direct compression. Meanwhile, increasing the percentage of HEP in the formulations caused a decrease in drug release rates. Moreover, DS release from the HEP tablets was much higher at high pH (6.8) than that at low pH (1.2). Morphology studies proved the HEP tablet formed a continuous gel layer with porous inner structure in the dissolution media. Analysis of DS release profiles revealed that diffusion and matrix erosion occurred in simulated intestinal fluid(SIF, pH = 6.8) for all the tablets. The experimental results predict HEP has a potential as a hydrophilic matrix in tablets to prolong drug release.