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Abstract

The aim of this work is the study of stability and kinetics of hydrolysis of the chosen compounds, derivatives of 2-hydroxy-3-[2-(4-methoxyphenyl)ethylamino]propyl-4- [(alkoxycarbonyl)amino]benzoates and 2-hydroxy-3-[2-(2-methoxyphenyl)ethylamino] propyl-4-[(alkoxycarbonyl)amino]benzoates with potential ultra-short beta-adrenolytic activity. The studied compounds are different in the position of the substituent on the benzene ring in the side chain as well as in the aromatic ring in position 4 with alkyl- (methyl- to butyl-) carbamate. Thin layer chromatography and UV-area spectrophotometry are used in order to establish the stability of these potential pharmaceuticals. The stability studies of the compounds were examined in acidic and alkaline media, in buffers and due oxidation at room and at elevated temperature chromatographically, and Rf values of incipient products and degradation products were detected. Kinetics of acid and base hydrolysis in various solutions at temperatures 80 °C and 100 °C were examined through UV-area spectrophotometry. Kinetic parameters such as rate constant k, half-life period t1/2 and usable life t90 were determined.

Abstract

The aim of this paper is the study of physico-chemical properties of the chosen compounds, derivatives of 2-hydroxy-3-[2-(4-methoxyphenyl) ethylamino]propyl-4-[(alkoxycarbonyl)amino]benzoates and 2-hydroxy-3-[2-(2-methoxyphenyl)ethylamino]propyl-4-[(alkoxycarbonyl) amino]benzoates with potential ultra-short beta-adrenolytic activity. The studied compounds are different in the position of the substituent on the benzene ring in the side chain as well as in the aromatic ring in position 4 with alkyl- (methylto butyl-) carbamate. The physico-chemical characteristics, for example, lipophilicity, surface activity, adsorbability, acidobasic properties etc., are very important for the explanation of the relationship between structure and biological activity of the drug. These parameters serve as the base of quantitative structure-activity study. The goal of this work is to establish the spectral characteristics of studied compounds in UV-area, pKa values, the parameters of lipophilicity (the values of Rf and RM from thin layer chromatography, retention time t´R and capacity factor k´ from liquid chromatography and experimental partition coefficients log P´ values), surface tension, critical micelle concentrations, the adsorbability of compounds expressed by percent of adsorbed compound on active charcoal β% as well as by Freundlich adsorption isotherms. The obtained values are correlated with the parameters characterising the size of molecule, for example, the number of carbon atoms on carbamate functional group.