Glass transitions in binary drug + polymer systems

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• 作者：R. Jayach ; ra Babu ; Witold Brostow ; Ioannis M. Kalogeras ; Sateesh Sathigari
• 关键词：Glass transition temperature ; Drug encapsulation ; Miscibility ; Efavirenz
• 刊名：Materials Letters
• 出版年：2009
• 出版时间：31 December 2009
• 年：2009
• 卷：63
• 期：30
• 页码：2666-2668
• 全文大小：397 K

文摘

To evaluate miscibility, glass transition temperatures T_g have been determined for two binary polymer (Plasdone S-630 copovidone or Eudragit® E) + drug systems as a function of composition. Each polymer serves for encapsulation of the anti-HIV drug Efavirenz. In both systems the T_g vs. drug concentration diagrams are s-shaped. T_gs of Efavirenz + Plasdone mixtures with drug mass fraction below φ_drug = 0.6 are above linear values. This implies enhanced thermal and mechanical stability—an advantage for the drug encapsulation. In the other system, a strong negative deviation of T_gs is observed over the entire compositional range and explained by positive excess mixing volumes. Several equations are used to represent T_g vs. composition diagrams, but only one (Brostow et al. Mater Lett 2008; 62:3152) provides reliable results.