Compatibility Studies Of Reserpine And Different Grades Of Hydroxypropyl Methyl Cellulose Polymer In Sustained Release Formulation

The main purpose of the current study was to examine the drug-excipient compatibility of reserpine with different grades of hydroxypropyl methylcellulose (HPMC) and common pharmaceutical excipients to produce a sustained-release oral formulation. Extensive preformulation studies were done to evaluate the physicochemical stability and compatibility of reserpine in the solid state. The melting point of reserpine, measured by the capillary method, was 241-241.5 °C. This value is very close to the range reported in the reference and confirms the drug's purity and thermal stability. Drug-excipient compatibility studies involved the preparation of physical mixtures of reserpine with lactose DC grade, HPMC K100 LV, HPMC K100 M, microcrystalline cellulose (MCC PH, 102), Aerosil, and magnesium stearate in a 1:1 ratio. These mixtures were kept under accelerated-stability conditions (40 ± 2 °C and 75 ± 5 % RH), and the initial, 14-day, and 28-day samples were analyzed using Fourier Transform Infrared (FTIR) spectroscopy. FTIR spectral analysis revealed that the characteristic functional group peaks of reserpine were preserved, with no additional peaks or significant shifts. In other words, no chemical interactions were detected. Spectral similarity indices after 14 days ranged from 0.981 to 0.998 and after 28 days from 0.980 to 0.995, thus demonstrating excellent compatibility of reserpine with all tested excipients.