Design, Formulation and In Vitro Evaluation of Sustained Release Matrix Tablets of Trazodone Hydrochloride

Abstract

The present study aimed to develop and evaluate sustained -release matrix tablets of Trazodone Hydrochloride using a hydrophilic matrix system to achieve prolonged drug release and improve patient compliance. Preformulation studies were carried out to characterize the drug, including particle size analysis, melting point determination, UV spectroscopy, FTIR spectroscopy, and differential scanning calorimetry (DSC). Drug – excipient compatibility studies confirmed the absence o f significant interactions between Trazodone Hydrochloride and the selected excipients. Seven formulations (F1 – F7) were prepared by direct compression using varying concentrations of release - retarding polymers. The powder blends were evaluated for micromer itic properties, showing good flowability and compressibility with Carr’s index below 15%, Hausner’s ratio below 1.20, and angle of repose below 30°. The compressed tablets were assessed for weight variation, hardness, thickness, friability, drug content, and in vitro dissolution performance. All formulations complied with pharmacopoeial requirements.Among the developed formulations, F5 demonstrated the most desirable sustained -release characteristics, exhibiting 38.4% drug release at 4 h, 63.4% at 8 h, 80.5% at 12 h, and 98.8% at 24 h. The formulation also showed excellent tablet properties, including opti mum hardness (5.8 kg/cm²), low friability (0.42%), and high drug content (99.82%). Drug release kinetic modelling revealed that the optimized formulation followed the Higuchi model (R² = 0.996), indicating diffusion - controlled drug release. The Korsmeyer – P eppas release exponent (n = 0.63) suggested a non - Fickian diffusion mechanism involving both diffusion and polymer relaxation.Accelerated stability studies conducted at 40 ± 2°C/75 ± 5% RH for three months demonstrated that the optimized formulation remained physically and chemically stable, with negligible changes in drug content and dissolution profile. The study concludes that sustained -release matrix tablets of Trazodone Hydrochloride can be successfully formulated using an appropriate polymer matrix system to provide controlled drug release over 24 hours.