کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2084059 | 1545374 | 2010 | 5 صفحه PDF | دانلود رایگان |

PurposeGlass transition temperature (Tg) measurements of polymers are conventionally conducted in the dry state with little attention to the environment they are designed to work in. Our aim was to develop the novel use of dynamic mechanical analysis (DMA) to measure the Tg of enteric polymethacrylic acid methylmethacrylate (Eudragit L and S) polymer films formulated with a range of plasticizers in the dry and wet (while immersed in simulated gastric media) states.MethodsPolymer films were fabricated with and without different plasticizers (triacetin, acetyl triethyl citrate, triethyl citrate, polyethylene glycol, propylene glycol, dibutyl phthalate, dibutyl sebacate). Tg was measured by a dynamic oscillating force with simultaneous heating at 1 °C/min. This was conducted on films in the dry state and while immersed in 0.1 M HCl to simulate the pH environment in the stomach.ResultsThe Tg of unplasticized Eudragit L and S films in the dry state was measured to be 150 and 120 °C, respectively. These values were drastically reduced in the wet state to 20 and 71 °C for Eudragit L and S films, respectively. The plasticized films showed similar falls in Tg in the wet state. The fall in Tg of Eudragit L films to below body temperature will have far-reaching implications on polymer functionality and drug release.ConclusionsImmersion DMA provides a robust method for measuring Tg of polymer films in the wet state. This allows better prediction of polymer behaviour in vivo.
Glass transition measurements of enteric methacrylic acid methyl methacrylate copolymer films while immersed in liquid media reveal a drastic drop in the glass transition to below body temperature. In situ measurements using immersion DMA allows better prediction of enteric coat behavior in vivo.Figure optionsDownload as PowerPoint slide
Journal: European Journal of Pharmaceutics and Biopharmaceutics - Volume 76, Issue 3, November 2010, Pages 493–497