Crucq A S, Tilquin B L, Hickel B
Unité d'Analyse Chimique et Physico-Chimique des Médicaments, Université Catholique de Louvain, Bruxelles, Belgique.
Free Radic Biol Med. 1995 May;18(5):841-7. doi: 10.1016/0891-5849(94)00204-w.
Radiosterilization induces radicals, and it is very important to describe radical mechanisms before the possible use of cephalosporins gamma sterilization. Moreover, physiological or radiotherapeutically induced free radicals also initiate radical mechanisms. For this study, pulse radiolysis was used. This method permits to avoid in vivo direct study difficulties of bioradical processes and gives quantitative data. Reactions of solvated electron (eaq-), hydroxyl radical (.OH), azide radical (N3.), dibromine radical anions (Br2.-), oxygen, and superoxide radical (O2.-) with three cephalosporins have been studied. Absorption spectra and rate constants have been determined. It has been found that both eaq- and .OH quickly react (k congruent to 10(10) mol-1 L s-1) with the molecules to give radicals with similar absorption spectra. N3. gives an absorption spectra that has been attributed to an electron transfer, whereas a part of .OH and Br2.- could add themselves to an unsaturated bond.
辐射灭菌会产生自由基，在可能使用头孢菌素γ灭菌之前描述自由基机制非常重要。此外，生理或放射治疗诱导的自由基也会引发自由基机制。在本研究中，使用了脉冲辐解。该方法可以避免生物自由基过程体内直接研究的困难，并给出定量数据。研究了溶剂化电子（eaq-）、羟基自由基（·OH）、叠氮自由基（N3·）、二溴自由基阴离子（Br2·-）、氧气和超氧自由基（O2·-）与三种头孢菌素的反应。测定了吸收光谱和速率常数。已发现eaq-和·OH都能迅速与分子反应（k约为10^10 mol^-1 L s^-1），生成具有相似吸收光谱的自由基。N3·产生的吸收光谱归因于电子转移，而一部分·OH和Br2·-可能会加成到不饱和键上。
