کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1208924 965323 2006 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Background electrolytes in 50% methanol/water for the determination of acidity constants of basic drugs by capillary zone electrophoresis
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Background electrolytes in 50% methanol/water for the determination of acidity constants of basic drugs by capillary zone electrophoresis
چکیده انگلیسی

The acidic dissociation constants of several hydrophobic drugs, amiodarone and a series of antidepressants that show a secondary or tertiary amino group, were determined in a 50% methanol/water mixture by capillary zone electrophoresis. The electrophoretic behavior of buffers prepared from sodium acetate, tris(hydroxymethyl) aminomethane hydrochloride, sodium hydrogenphosphate, ammonium chloride, ethanolamine, butilammonium chloride, and sodium borate in the hydroalcoholic solution was tested. Thus, all of them follow the Ohm's law until about 25 kV and, therefore, they can be used without significant Joule heat dissipation at 20 kV. For the studied drugs, buffers prepared with phosphate or borate give effective mobility measurements lower than those from other buffers. The wide pKa range of the studied drugs provides a wide pH range where the protonated forms of the amino compounds coexist with hydrogenphosphate ions and where the neutral amines coexist with boric acid. The decrease of the experimental effective mobilities in these instances can be explained through the interactions between coexisting species. Therefore, phosphate and borate buffers should be avoided to determine the mobility of amines with aqueous pKa higher than 8, at least in solutions with high methanol content. Independent measurements of acidic dissociation constants of drugs validate this statement.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Chromatography A - Volume 1123, Issue 1, 4 August 2006, Pages 113–120
نویسندگان
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