Effect of plasticizer on drug crystallinity of hydroxypropyl methylcellulose matrix film.

Effect of different hydrophilic plasticizers on drug crystallinity of hydroxypropyl methylcellulose (HPMC) matrix film was studied. HPMC films containing telmisartan using different plasticizers were prepared by casting method. Drug crystallinity in the films was examined using polarized light microscopy (PLM), scanning electron microscopy (SEM), and x-ray diffractometry (XRD) to describe their phase behavior/solid state miscibility/crystal growth and drug-polymer-plasticizer interaction. HPMC and plasticizer were compatible with the drug and no phase separation was observed upon solvent evaporation. Plasticized-HPMC contributed a major role in the significant inhibition of crystal growth of the drug in the film. The triethanolamine film produced a relatively smooth surface in comparison to the other films in the submicron level. The films have not shown any significant changes even after exposure to stress (40°C/75% RH, 6 w). Triethanolamine as plasticizer brought about amorphization of telmisartan to the maximum extent in the film which is technologically more advantageous than the others owing to its anticipated better bioavailability.