کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2487711 | 1114428 | 2007 | 11 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Processing-Induced Phase Transitions of Theophylline—Implications on the Dissolution of Theophylline Tablets Processing-Induced Phase Transitions of Theophylline—Implications on the Dissolution of Theophylline Tablets](/preview/png/2487711.png)
Aqueous wet massing of stable anhydrous theophylline (A) with polyvinylpyrrolidone (PVP) resulted in its complete transformation to theophylline monohydrate (M). Drying at 45°C, resulted in the formation of metastable anhydrous theophylline (A*) which then transformed to A. PVP, a known crystallization inhibitor, was effective in inhibiting the A* → A transition. The higher molecular weight polymer, PVP K90, was more effective in inhibiting the A* → A transition as compared to PVP K17. The disappearance of M, and the formation of A* and A was simultaneously monitored by XRD. An increase in the drying temperature from 45 to 55°C accelerated the A* → A transition. In granules prepared by the high-shear process, approximately 50% of theophylline existed as A and the rest as A*. In contrast, the fluid-bed granulation process yielded granules containing only A. Thus, the physical form of theophylline in tablets was influenced by the molecular weight of the binding agent, the granulation method, and the drying temperature. Using A as the starting material, tablets were manufactured by high-shear aqueous wet granulation process and the A* content was quantified. These tablets were stored under various relative humidity (RH) conditions at 25°C for 2 weeks. Storage at RH ≥ 33% caused complete A* → A conversion accompanied by a pronounced decrease in the initial dissolution rate indicating that phase transitions during processing and storage can have a significant influence on product performance.
Journal: Journal of Pharmaceutical Sciences - Volume 96, Issue 5, May 2007, Pages 1434–1444