title: Mechanistic evaluation of the effect of thermal-treating on Eudragit RS matrices.
abstract: Thermal treatment of acrylic matrices was recently introduced as a tool for prolonging the release of drug. Thermal treatment at temperatures above the T(g) of the polymer can decrease drug release rate. In this research we studied the mechanism of the effect of thermal treatment on Eudragit RS matrices. Indomethacin was used as model drug. The results showed that polymer chain movement and redistribution of the polymer in the tablet matrix structure after thermal-treating is the possible mechanism of drug release prolongation. The melting and resolidification of the polymer, due to the thermal treatment has apparently resulted in a redistribution of the polymer throughout the matrix and a change in the porosity of the tablet. FTIR results did not show any drug-polymer interaction due to heat-treatment. DSC and PXD studies ruled out the occurrence of solid solution and polymorphic change of the drug.
authors.affiliation: Department of Pharmaceutics, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz 51664, Iran.
authors.forename: Shirzad
authors.initials: S
authors.lastname: Azarmi
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Ghaffari
authors.forename: Raimar
authors.initials: R
authors.lastname: Löbenberg
authors.forename: Ali
authors.initials: A
authors.lastname: Nokhodchi
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry; D003692:Delayed-Action Preparations; D004337:Drug Carriers / Q000737:chemistry*; D006358:Hot Temperature; D007213:Indomethacin / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013607:Tablets; D013997:Time Factors
chemical_list: D000180:Acrylic Resins; D000894:Anti-Inflammatory Agents, Non-Steroidal; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D011108:Polymers; D013607:Tablets; C050528:Eudragit RS; D007213:Indomethacin