Thermal aging phenomena in chitosan-related pharmaceutical systems

Autor:	T. Pawlowski, K.H. Bodek, G.W. Bak, B. Hilczer
Rok vydání:	2001
Předmět:	Analytical chemistry Cationic polymerization Dielectric Charge-transfer complex Dielectric spectroscopy Chitosan chemistry.chemical_compound symbols.namesake chemistry Chemical engineering Desorption symbols Dielectric loss Electrical and Electronic Engineering Raman spectroscopy
Zdroj:	IEEE Transactions on Dielectrics and Electrical Insulation. 8:555-558
ISSN:	1070-9878
DOI:	10.1109/94.933383
Popis:	Results are presented of detection of thermal aging in the chitosan/ketoprofen acid (KTA) system, using low-frequency dielectric spectroscopy. Aging leads to substantial changes of the low frequency dielectric properties of the system. In order to identify the reasons for the detected aging, near infra-red (NIR) Raman spectra and distribution of molecular weights as well as direct measurements of water content were carried out. The additional measurements suggest that water desorption is mainly responsible for the detected aging phenomena. Formation of a charge transfer complex between the anionic carbonyl group of KTA and the cationic NH3/sup +/ group of chitosan, has also been detected.
Databáze:	OpenAIRE
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