Development and In Vitro Characterization of a HPMC K4M and Guar Gum-Based Triple-Layer Matrix Tablet System for Chondroitin Sulphate and Diclofenac Sodium

This investigation aimed to make a triple-layer matrix tablet for the oral sustained release of chondroitin (CTN) and diclofenac sodium (DFC) to prolong their therapeutic action. Matrix tablet granules containing CTN and DFC were prepared using wet granulation with Hydroxy propyl methylcellulose (HPMC) K4M and guar gum. A triple-layer tablet structure was fabricated by sequentially compressing three layers: a central layer containing the drug-loaded matrix granules, flanked by two release retardant layers on each side. The retardant layers comprised varying proportions (50-100 mg) of HPMC K4M (X1) and guar gum (X2) as inputs for the responses, cumulative drug release, and swelling index. The physicochemical properties and drug compatibility were evaluated. In-vitro drug dissolution outlines were determined and fitted to numerous mathematical models to elucidate the drug release kinetics and mechanism. The physicochemical evaluations indicated acceptable tablet properties and drug compatibility. Mathematical modeling of the dissolution profiles revealed that the drug release from the matrix tablets was best described by a model indicative of heterogeneous erosion. Formulation F-7, containing 75 mg of HPMC K4M and 39.65 mg of guar gum in the retardant layers, demonstrated the ability to sustain the drug release rate over an extended period. The developed triple-layer matrix tablet system, particularly formulation F-7, offers a promising approach for achieving sustained CTN and DFC oral delivery. The drug release mechanism was known to be predominantly governed by heterogeneous erosion of the matrix. The optimized formulation could enhance patient obedience by reducing the rate of drug administration.