Ferrit M, Del Valle C, López M, Luque R, Martínez F
Department of Physical Chemistry, Faculty of Pharmacy, Campus of Cartuja s/n/18071, University of Granada, Spain.
J Pharm Sci. 2004 Feb;93(2):461-9. doi: 10.1002/jps.10543.
The new platelet antiaggregant Triflusal or 2-acetoxy-4-trifluoromethylbenzoic acid presents a structural analogy to acetylsalicylic acid (ASA). Alkaline hydrolysis of triflusal was studied in the presence and absence of cationic micelles of N-cetyl-N-ethyl-N,N-dimethylammonium bromide (CDEABr) at different KOH concentrations and different temperatures (25, 30, and 37 degrees C) using a spectrophotometric method. The influence of potassium bromide concentration upon alkaline hydrolysis at 25 degrees C is also discussed. At constant [KOH] pseudofirst-rate constant (k(obs)) decreased with increasing [CDEABr] at concentrations greater than the CMC and also decreased with increasing [KBr] at constant [KOH] and [CDEABr]. To explain the effect of cationic micelles of CDEABr upon alkaline hydrolysis, the pseudophase ion exchange model was used. The values of the micellar properties such as the critical micelle concentration, the degree of micellar ionization and the neutralized fraction of the head group obtained by conductivity measurements were determined previously.
新型血小板抗聚集剂曲氟尿苷或2-乙酰氧基-4-三氟甲基苯甲酸与乙酰水杨酸（ASA）存在结构相似性。采用分光光度法，在不同氢氧化钾浓度和不同温度（25、30和37摄氏度）下，研究了在有和没有N-十六烷基-N-乙基-N,N-二甲基溴化铵（CDEABr）阳离子胶束存在的情况下曲氟尿苷的碱性水解。还讨论了溴化钾浓度对25摄氏度下碱性水解的影响。在恒定的[KOH]下，当浓度大于临界胶束浓度（CMC）时，准一级速率常数（k(obs)）随[CDEABr]的增加而降低，并且在恒定的[KOH]和[CDEABr]下，也随[KBr]的增加而降低。为了解释CDEABr阳离子胶束对碱性水解的影响，使用了假相离子交换模型。通过电导率测量获得的胶束性质值，如临界胶束浓度、胶束电离度和头部基团的中和分数，先前已确定。
