Sou Huei Chen, R. Kenley, J. S. Winterle
May 27, 1991
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0
Influential Citations
2
Citations
Journal
International Journal of Pharmaceutics
Abstract
Abstract Sulconazole (1-[2-{[4-chlorophenyl)methyl]thio}-2-(2,4-dichlorophenyl)ethyl]-1H-imidazole) is one member of a family of antimycotic drugs. Because oxidative degradation frequently limits the shelf lives of sulfur-containing drugs, we investigated the oxidation kinetics of sulconazole and sulconazole sulfoxide in aqueous peracetic acid and hydrogen peroxide. The oxidations were studied as a function of pH (7–13) and of the concentration of peracetic acid (0.025–25 mM) and of hydrogen peroxide (100–1000 mM). Our objective was to probe the effects of peroxide structure and charge state on sulconazole loss rates and product distributions. In the presence of peroxyacetic acid or hydrogen peroxide, sulconazole converts quantitatively to the corresponding sulfoxide and sulfone. Solution pH strongly influences the overall product distribution at intermediate extents of conversion. Thus, alkaline pH favors sulfone accumulation whereas sulfoxide predominates in acidic solution. The observed relative reactivities toward sulconazole are: peroxyacetic acid (105), peroxyacetate anion (103), hydrogen peroxide (1), and hydroperoxy anion (1). Transition state intramolecular proton transfer remains the most straightforward explanation for the dependence of sulconazole oxidation rates on peroxide structure and charge state.