ABSTRACT
The mechanical and dielectric properties of three kinds of poly(lactic acid-coglycolic acid) (PLG) with different molecular weights and polydispersities fractioned by ultrafiltration were investigated by dynamic mechanical thermal analysis (DMTA) and dielectric measurement. All samples showed typical behaviour of amorphous polymer under different fields. Two relaxation processes were found, a secondary relaxation in glassy state at low temperature and a glass transition relaxation. The molecular weights and polydispersities of PLGs influenced significantly both relaxation, especially the relaxation strength and location. The strength of secondary relaxation was reduced and the glass transition shifted to a higher temperature when the molecular weight of PLG increased and the polydispersity decreased. The shift of glass transition temperature (Tg) might decrease the motion of the macromolecules and resulted in a higher moduli of rubbery PLG at the temperature of the drug system (37 degrees C) and lowered the diffusivity of the drug in polymeric matrix and then the initial burst and fast diffusional release of captopril from commercial PLG were improved.
Subject(s)
Captopril/administration & dosage , Captopril/pharmacokinetics , Biocompatible Materials , Biodegradation, Environmental , Capsules , Captopril/chemistry , Delayed-Action Preparations , Drug Carriers , Drug Delivery Systems , Electrochemistry , Lactic Acid , Microspheres , Molecular Weight , Polyglycolic Acid , Polylactic Acid-Polyglycolic Acid Copolymer , Polymers , Thermodynamics , UltrafiltrationABSTRACT
In the offices of 26 general practitioners in Upper Franconia, Germany, a complete survey of all type II diabetics was carried out. A total of 2,180 type II diabetics were analyzed in terms of age, sex and treatment with diet alone, tablets, or insulin. On average, each office is looking after 7.8% such diabetics, whose median age was 70 years, with 79% being older than 60. The considerable difference in the distribution of diabetics treated with diet alone, tablets or insulin among the various doctor's offices are discussed. The significance of inter-physician differences with respect to decision-making, e.g. when to start the patient on insulin, is examined. The data point up a need for the auditing of general practitioners.
