Department of Pharmaceutical Sciences, University of Calabria, Via P Bucci, 87036 Rende, Cosenza, Italy.
Int J Pharm. 2010 Feb 15;386(1-2):99-107. doi: 10.1016/j.ijpharm.2009.11.003. Epub 2009 Nov 10.
This work aims at describing the kinetic model of nitrofurazone photodegradation by a novel chemometric technique, hybrid hard-soft multivariate curve resolution (HS-MCR). The study was applied to UV-spectral data from the photolysis of nitrofurazone solutions at different concentrations and exposed under varying illuminance power. The HS-MCR method was able to elucidate the kinetics of the photodegradation process and to determine the rate constants, and estimating at the same time the pure spectra of the degradation products. Exposure to light of the drug gave a first rapid isomerization to the syn-form that in turn underwent degradation furnishing a mixture of yellow-red products. The photodegradation process could be explained with a kinetic model based on three consecutive first-order reactions (A>B, B>C and C>D). These results were confirmed by application of the MCR procedure to the analysis of the data obtained from HPLC-DAD analysis of the nitrofurazone samples at different reaction times. The kinetic model was observed to be dependent on experimental conditions. The samples at higher concentrations showed rate constants lower than the diluted samples, whereas an increase of the rate of all degradation processes was observed when the light power also increased. This work shows the power of the hybrid hard- and soft-multivariate curve resolution as a method to deeply study degradation processes of photolabile drugs.
本工作旨在描述利用一种新的化学计量学技术，即混合硬软多变量曲线分辨（HS-MCR），对呋喃西林光降解的动力学模型进行描述。该研究应用于不同浓度的呋喃西林溶液在不同光照强度下的光解紫外光谱数据。HS-MCR 方法能够阐明光降解过程的动力学，并确定速率常数，同时估计降解产物的纯光谱。药物暴露在光线下首先迅速异构化为顺式，顺式继而发生降解，生成黄色红色产物的混合物。光降解过程可以用一个基于三个连续一级反应（A>B、B>C 和 C>D）的动力学模型来解释。这些结果通过将 MCR 程序应用于在不同反应时间下用 HPLC-DAD 分析呋喃西林样品得到的数据的分析得到了证实。动力学模型观察到依赖于实验条件。高浓度样品的速率常数低于稀释样品，而当光照强度增加时，所有降解过程的速率都增加。这项工作展示了混合硬软多变量曲线分辨作为一种深入研究光不稳定药物降解过程的方法的强大功能。
