کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2487360 | 1114413 | 2008 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Calorimetric Relaxation and the Glass-Liquid Temperature Range of Acetaminophen-Nifedipine Alloys
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کلمات کلیدی
موضوعات مرتبط
علوم پزشکی و سلامت
داروسازی، سم شناسی و علوم دارویی
اکتشاف دارویی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Glassy states of nine acetaminophen-nifedipine compositions have been made by slowly supercooling their melts, and calorimetric Tg and the nonexponential, nonlinear relaxation parameters β and x that are used in modeling the mobility of a pharmaceutical determined. The Tg-endotherm's shape varies with the alloy's composition, Tg increases approximately linearly with the mol% of nifedipine, β and x increase, and the activation enthalpy Îh* decreases. At Tg, the relaxation time Ïcal of acetaminophen, nifedipine, and their alloys differs from 100 s to different extents. The distribution of relaxation times is lesser than that for polymers and other glasses. For a given composition, Îh*, β, x, and Ïcal anomalously depend upon the heating rate, indicating that variation of β with temperature would not yield better fits for modeling their stability. It is suggested that a pharmaceutical's relaxation is generally influenced by changes in intermolecular hydrogen bonds, chemical short-range order, vibrational frequency, isomerization, and impurity electrolyte dissociation, all of which contribute to the energy change with a distinctive kinetics.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Pharmaceutical Sciences - Volume 97, Issue 8, August 2008, Pages 3233-3244
Journal: Journal of Pharmaceutical Sciences - Volume 97, Issue 8, August 2008, Pages 3233-3244
نویسندگان
Gyan P. Johari, Ravi M. Shanker,