Abstract
This study was carried out with the aim of formulating, optimizing, and assessing Simvastatin extended-release matrix tablets by using different viscosity grades and concentrations of Hydroxypropyl Methylcellulose (HPMC) via the direct compression method. Preformulation investigations, such as determination of the melting point, solubility, and drug-excipient compatibility by means of FTIR spectroscopy, were conducted in order to ascertain the appropriateness of the drug and the excipients. Twelve formulations (F1 to F12) were prepared using HPMC K4M, HPMC K15M and HPMC K100M together with ethyl cellulose and other appropriate excipients. The powder blends and the resulting tablets were examined for their pre-compression and post-compression properties, and in-vitro drug-release studies were then performed. Of the formulations, F12 was chosen as the optimized one since it achieved about 98% cumulative drug release within 24 hours and had acceptable tablet characteristics. The release kinetics of formulation F12 correlated most closely with the Korsmeyer–Peppas model (R² = 0.9969), then with the Higuchi model (R² = 0.9834), which indicates that both diffusion and polymer relaxation play a role in the drug release process. Accelerated stability testing, carried out at 40 ± 2°C and 75 ± 5% RH for a period of two months, revealed only slight changes in the parameters under examination, showing that the optimized formulation is stable. The study as a whole showed that HPMC-based hydrophilic matrix technology is a suitable method for extending the in-vitro release of Simvastatin, F12 displaying the most favourable release profile under the experimental conditions.