Application of in-line viscometer for in-process monitoring of microcrystalline cellulose-carboxymethylcellulose hydrogel formation during batch manufacturing

Physical stability and consistent dose delivery of pharmaceutical suspension formulations comprised of microcrystalline cellulose (MCC) and sodium carboxymethylcellulose (NaCMC) hydrogels is dependent on their rheological properties. To obtain the desired rheological characteristics, good control of the hydrogel dispersion in water is required. The goal of this study was to evaluate whether the XL7-100 Process Viscometer could be employed as a process analytical technology (PAT) tool to monitor the dispersion process in real time during batch manufacturing. Using this instrument, viscosity profiles were measured during the hydrogel processing for a range of operating conditions. It was confirmed that viscosity obtained by the XL7-100 Process Viscometer in the off-line mode, could be linearly correlated to that of the conventional Brookfield viscometer. In addition, the XL7-100 Process Viscometer was able to detect variations in the hydrogel concentrations as well as process conditions in real time. Under fixed operating conditions, the dynamic viscosity profile showed low variability and good inter-batch reproducibility for a properly dispersed hydrogel. For a well-validated mixing process, an off-trend in-line viscosity reading may be indicative of batch failure or poor dispersion homogeneity. Therefore, the in-line viscometer can be used in manufacturing to monitor the batch to batch consistency. However, it is not proven to be able to characterize the real-time structure formation of the hydrogel. It is recommended that the in-line viscometer be used as a complimentary tool along with the off-line rheometer for both efficient and effective in-process quality control of the MCC & NaCMC hydrogel dispersion.     

ε-聚赖氨酸与羧甲基纤维素钠的相互作用

以ε-聚赖氨酸（ε-polylysine,ε-PL）与羧甲基纤维素钠（sodium carboxymethylcellulose,CMC-Na）相互作用体系的混浊度、Zeta电位和粒度为指标,研究了CMC-Na的取代度（degree of substitution,DS）和相对分子质量对ε-PL/CMC-Na相互作用体系的影响。结果表明,在pH 4.0时,ε-PL与CMC-Na之间的静电相互作用主要依赖于ε-PL氨基与CMC-Na羧基的物质的量比;同时,CMC-Na的取代度和相对分子质量均对ε-PL/CMC-Na相互作用具有显著影响,且CMC-Na取代度对体系稳定性的影响更大。     

羧甲基纤维素取代均一性的研究

羧甲基纤维素(钠盐,以下简称CMC)是一种重要的水溶性聚电解质。本文在传统溶媒法的基础上,采用乙醇作溶剂的两段加碱法新工艺制备CMC。研究表明,在低浴比(乙醇/纤维素=2.5—3.0)条件下,采用新工艺制得取代度约0.9,粘度(2％水溶液)为900—1000mPa·s,具有较高取代均一性和良好性能的CMC。用酶水解的方法,通过还原值测定,对CMC的取代基沿分子链的分布进行了表征;并对CMC的一些性能进行了测定,同时对其热稳定性进行了研究。     

苦味酸-羧甲基纤维素酯的稳定性及其对维生素B6的吸附性能

苦味酸羧甲基纤维素酯(CMC-PA)是一种对肌酐具有良好吸附性能的新型纤维素衍生物,在前期苦味酸羧甲基纤维素酯(CMC-PA)合成和对肌酐的吸附性能分析的基础上,进一步研究其稳定性以及对维生素B6的吸附性能。在模拟人体生理介质的条件下,采用紫外分光光度法(UV),以358nm为测定波长,分析了pH、水解时间以及放置时间对CMC-PA稳定性的影响;以303nm为测定波长,测定了在不同吸附时间下CMC-PA对维生素B6的吸附性能。研究结果表明,4～6h在pH分别为1、2、8的缓冲溶液中,CMC-PA的水解率分别为0.47%～0.69%、0.213%～0.226%、1.318%～1.418%,室温下放置2、4、6、8个月后,37℃时对肌酐的吸附容量与新制CMC-PA相比没有发生明显的变化。另外,CMC-PA在不同时间条件下,对维生素B6没有明显的吸附。     

不同涂膜保鲜剂对蒙自甜石榴冷藏品质的影响

目的探讨羧甲基纤维素钠(CMC)、海藻酸钠、魔芋和果胶4种涂膜保鲜剂对冷藏石榴品质的影响。方法以蒙自"甜绿籽"石榴为试验材料,涂膜处理后,在(5±1)℃低温冷藏,测定石榴籽粒中可溶性固形物、总糖、总酸、维生素C和腐烂率等指标随冷藏时间的变化。结果果胶涂膜处理能显著延缓贮藏期间可溶性固形物、总糖、总酸含量的下降,提高冷藏期间石榴的营养品质,效果优于其他涂膜保鲜剂;CMC涂膜处理能显著降低石榴的腐烂率,可延缓维生素C和可溶性固形物的损失;海藻酸钠涂膜处理可延缓可溶性固形物含量的降低,但是对维生素C、总糖、总酸和腐烂率无显著效果;魔芋涂膜处理能延缓总糖、总酸含量的下降,但是使腐烂率显著升高。结论果胶和CMC涂膜处理对冷藏石榴均有良好的保鲜效果。     

羧甲基纤维素制备方法及其生产工艺研究进展

介绍了羧甲基纤维素(CMC)的关键技术指标,并从羧甲基化反应机理出发,在回顾传统制备方法的基础上,综述了近年来国内外关于纤维素羧甲基化反应和工艺的研究进展,重点评述了对体系反应介质的种类和组成、溶液法、新原料、溶媒法工艺的改进、羧甲基化工艺与其他产品生产工艺的耦合等问题,并对其发展前景进行了展望。     

CPC-B/CMC有机复合膨润土凝胶的制备及表征

以辽宁黑山钠基膨润土为原料,采用氯代十六烷基吡啶(CPC)和羧甲基纤维素钠（CMC）为改性剂对膨润土(B)进行改性处理,制得复合凝胶吸附剂（CMC/CPC-B）。采用单因素及响应面分析法对制备工艺进行了优化,并利用SEM和XRD测试手段进行结构表征分析。结果表明,CMC/CPC-B的最佳制备条件为：CMC与CPC-B投加量（质量）比为4∶1,pH值为4,温度为60℃,交联剂（AlCl3）浓度为0.1 mol/L,制备的CMC/CPC-B吸附苯酚量最高,可达2.8329 mg/g。因素影响强弱顺序为pH值＞温度＞CPC-B投加量,交联剂浓度影响不显著。因素交互影响较小,只有pH值与配比交互影响显著,其它交互项影响均不显著。CPC-B/CMC结构上与原土及单改性土明显不同,由片层结构变为网状交联的凝胶结构;CPC-B与CPC-B/CMC的X射线衍射首峰与原土相比向小角度方向偏移,层间距明显增加,CPC-B/CMC的衍射峰位于原土与CPC-B衍射峰之间,经交联反应后层间距被交联结构占据而减小。     

微波辐射CMC接枝AA/AMPS高吸水树脂的制备

采用微波辐射方法制备了羧甲基纤维素钠(CMC)接枝丙烯酸(AA)/2-丙烯酰胺基-2-甲基丙磺酸(AMPS)高吸水性树脂,并用红外光谱对树脂进行了表征。探讨了交联剂用量、引发剂用量、单体配比、中和度和微波功率对树脂吸水性能的影响。实验结果表明:最佳合成条件下制备的高吸水性树脂吸蒸馏水倍率达690g/g,吸生理盐水倍率为90g/g;红外光谱分析表明:丙烯酸和2-丙烯酰胺基-2-甲基丙磺酸接枝到羧甲基纤维素钠分子链上。     

The influence of pH upon the hydrolysis of carboxymethylcellulose with cellulases from Trichoderma reesei

We have studied the enzymatic hydrolysis of carboxymethylcellulose (CMC) with Celluclast, a commercial preparation of cellulases deriving from Trichoderma reesei, by monitoring the variation in the concentrations of glucose and reducing sugars at a constant temperature of 50°C and different pH values. We determined both glucose and overall yield, concluding that the production of glucose directly by endoglucanase is higher than that coming from the hydrolysis of cellobiose by β‐1,4‐glucosidase and that the rate at which cellobiose is formed can be calculated via kinetic parameters that are due in the end mainly to exoglucanase activity. We observed the effect of pH upon the kinetic parameters and found that the ideal value for the hydrolysis of CMC is one of pH 4.9.