<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Papadopoulou, V.</style></author><author><style face="normal" font="default" size="100%">Kosmidis, K</style></author><author><style face="normal" font="default" size="100%">Vlachou, M.</style></author><author><style face="normal" font="default" size="100%">Macheras, P.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">On the use of the Weibull function for the discernment of drug release mechanisms</style></title><secondary-title><style face="normal" font="default" size="100%">INTERNATIONAL JOURNAL OF PHARMACEUTICS</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">controlled release</style></keyword><keyword><style  face="normal" font="default" size="100%">Drug release</style></keyword><keyword><style  face="normal" font="default" size="100%">mechanism</style></keyword><keyword><style  face="normal" font="default" size="100%">Power law</style></keyword><keyword><style  face="normal" font="default" size="100%">Weibull function</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2006</style></year><pub-dates><date><style  face="normal" font="default" size="100%">FEB 17</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">1-2</style></number><publisher><style face="normal" font="default" size="100%">ELSEVIER SCIENCE BV</style></publisher><pub-location><style face="normal" font="default" size="100%">PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS</style></pub-location><volume><style face="normal" font="default" size="100%">309</style></volume><pages><style face="normal" font="default" size="100%">44-50</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Previous findings from our group based on Monte Carlo simulations indicated that Fickian drug release from Euclidian or fractal matrices can be described with the Weibull function. In this study, the entire drug release kinetics of various published data and experimental data from commercial or prepared controlled release formulations of diltiazem and diclofenac are analyzed using the Weibull function. The exponent of time b of the Weibull function is linearly related to the exponent n of the power law derived from the analysis of the first 60% of the release curves. The value of the exponent b is an indicator of the mechanism of transport of a drug through the polymer matrix. Estimates for b &lt; 0.75 indicate Fickian diffusion in either fractal or Euclidian spaces while a combined mechanism (Fickian diffusion and Case 11 transport) is associated with b values in the range 0.75 &lt; b &lt; 1. For values of b higher than 1, the drug transport follows a complex release mechanism. (c) 2005 Elsevier B.V. All rights reserved.</style></abstract><work-type><style face="normal" font="default" size="100%">Article</style></work-type></record></records></xml>