Rudraraju Varma S, Wyandt Christy M
Hoffmann La Roche Inc., 340 Kingsland Street, Nutley, NJ 07110, USA.
Int J Pharm. 2005 Mar 23;292(1-2):63-73. doi: 10.1016/j.ijpharm.2004.10.012.
Rheological properties of two different commercial grades of Microcrystalline Cellulose/Sodiumcarboxymethyl Cellulose (MCC/NaCMC) hydrogels were investigated. Viscoelastic characterization of the hydrogels using a controlled stress rheometer revealed that structure formation in the gels could be detected at a concentration as low as 1.0% w/w MCC/NaCMC in purified water. The elastic modulus (G') and the linear viscoelastic region (LVR) increased with increase in hydrogel concentration. The frequency sweep study of the hydrogels exhibited a flat G', indicating a stable structure at 1.5% w/w and 2.0% w/w concentrations. The oscillation time sweep study indicated that the rate of structure build up was dependent on the concentration of hydrogel. Structure buildup at various temperatures indicated that structure formation was rapid at higher temperature (40 degrees C), and the gel point was reached fairly quickly. Phase volume of the hydrogel significantly influenced structural recovery at different temperatures.
研究了两种不同商业等级的微晶纤维素/羧甲基纤维素钠（MCC/NaCMC）水凝胶的流变特性。使用控制应力流变仪对水凝胶进行粘弹性表征，结果显示，在纯水中，当MCC/NaCMC浓度低至1.0% w/w时，就能检测到凝胶中的结构形成。随着水凝胶浓度的增加，弹性模量（G'）和线性粘弹性区域（LVR）增大。水凝胶的频率扫描研究显示G'呈平稳状态，表明在1.5% w/w和2.0% w/w浓度下结构稳定。振荡时间扫描研究表明，结构形成速率取决于水凝胶的浓度。在不同温度下的结构形成表明，在较高温度（40摄氏度）下结构形成迅速，且能较快达到凝胶点。水凝胶的相体积显著影响不同温度下的结构恢复。
