Title :
Thermal aging phenomena in chitosan-related pharmaceutical systems
Author :
Bak, G.W. ; Bodek, K.H. ; Hilczer, B. ; Pawlowski, T.
Author_Institution :
Inst. of Phys., Tech. Univ. Lodz, Poland
fDate :
6/1/2001 12:00:00 AM
Abstract :
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+ group of chitosan, has also been detected
Keywords :
Raman spectra; ageing; bioelectric phenomena; biomedical materials; biothermics; desorption; dielectric losses; molecular biophysics; molecular weight; organic compounds; permittivity; 1E-3 to 1E5 Hz; 5 hour; anionic carbonyl group; cationic NH3+ group; charge transfer complex; chitosan-related pharmaceutical systems; chitosan/ketoprofen acid system; drugs; low-frequency dielectric spectroscopy; low-frequency dispersion; molecular weight distribution; near infra-red Raman spectra; relative permittivity; thermal aging phenomena; water content; water desorption; Aging; Chemicals; Chemistry; Dielectric measurements; Digestive system; Drugs; Electrochemical impedance spectroscopy; Pharmaceuticals; Physics; Polymers;
Journal_Title :
Dielectrics and Electrical Insulation, IEEE Transactions on
