衰老对聚丙烯酸凝胶体系流变学、介电和黏膜黏附特性的影响。

The effects of ageing on the rheological, dielectric and mucoadhesive properties of poly(acrylic acid) gel systems.

作者信息

Tamburic S, Craig D Q

机构信息

Centre for Materials Science, School of Pharmacy, University of London, UK.

出版信息

Pharm Res. 1996 Feb;13(2):279-83. doi: 10.1023/a:1016003400886.

DOI:10.1023/a:1016003400886

PMID:8932449

Abstract

PURPOSE

The purpose of this study was to investigate the effects of storage on the physical properties of a series of poly(acrylic acid) (PAA) hydrogels, using two dynamic techniques, oscillatory rheology and dielectric spectroscopy. Furthermore, the effects of ageing on the mucoadhesive properties were evaluated and related to the changes in structure.

METHODS

Three carbomers (Carbopols 934P, 974P and EX-214) and polycarbophil (Noveon AA-1) have been formulated as hydrogels with a range of neutralising agents (NaOH, triethanolamine and tromethamine). The effects of storage for six months on the gel structure were measured using oscillatory rheology and low frequency dielectric analysis. Mucoadhesive performance was studied by means of a detachment force test.

RESULTS

A substantial decrease in the rheological storage moduli was noted for all samples, while the tan delta values remained unchanged for the majority of systems. Dielectric studies revealed that gels neutralised with triethanolamine showed a greater degree of binding of neutralising ions to the gel network than did the other two agents. It was also found by the dielectric analysis that, on storage, the distribution of ions within the gel systems changed. This may be due to the neutralising ions being liberated from the gel network into the bulk aqueous phase, thereby contributing to the decrease in rheological storage modulus. Mucoadhesion studies indicated that, despite the substantial changes in gel structure, there was no alteration in the bioadhesive force of detachment for the majority of systems during a six month period.

CONCLUSIONS

A redistribution of cations between the polymer cluster and the bulk of medium is proposed as a possible additional mechanism of ageing of PAA hydrogels. The results obtained support the hypothesis outlined previously that the mucoadhesive strength is related to the tan delta value rather than the viscosity of the gel.

摘要

目的

本研究旨在采用振荡流变学和介电谱这两种动态技术，研究储存对一系列聚丙烯酸（PAA）水凝胶物理性质的影响。此外，评估老化对黏膜黏附性能的影响，并将其与结构变化相关联。

方法

将三种卡波姆（卡波普934P、974P和EX - 214）和聚卡波非（诺维昂AA - 1）与一系列中和剂（氢氧化钠、三乙醇胺和氨丁三醇）配制成水凝胶。使用振荡流变学和低频介电分析来测量储存六个月对凝胶结构的影响。通过剥离力测试研究黏膜黏附性能。

结果

所有样品的流变储能模量均显著降低，而大多数体系的损耗角正切值保持不变。介电研究表明，用三乙醇胺中和的凝胶比其他两种试剂显示出更高程度的中和离子与凝胶网络的结合。通过介电分析还发现，储存时凝胶体系内离子的分布发生了变化。这可能是由于中和离子从凝胶网络释放到本体水相中，从而导致流变储能模量降低。黏膜黏附研究表明，尽管凝胶结构发生了显著变化，但在六个月期间大多数体系的生物黏附剥离力没有改变。