Le C. Equilibria in aqeous and micellar solution and analytical properties of aminodiphosphonic and amino acids

Investigated objects: the processes of dissociation aminodiphosphonic acids and amino acids in aqueous and micellar solutions of surfactants; the processes of separation in micellar thin-layer chromatography (TLC). Purpose: to determine the constants of protolytic equilibriums of aminodiphosphonic acids and amino acids in aqueous and micellar mediums, to support the possibilities of titrimetric determination of sodium alendronate and to develop new methods of quantitative determination of active ingredient and impurities control in drugs of sodium alendronate. Methods: potentiometry; micellar TLC; viscosimetry, measuring of surface tension; methods of mathematic simulation of equilibrium analytical systems. The dissociation constants of 4 aminodiphosphonic acids and 14 amino acids in aqueous and micellar solutions of surfactants have been obtained. The method of sodium alendronate quantitative titrimetric determination was developed. The method of micellar TLC was proposed for identification and quantitative determination of 4-aminobutyric acid impurity in sodium alendronate. The Giddins model was for the first time used in micellar TLC and the new explanation of alcohols-modifiers effect on the characteristics of chromatographic process was proposed. Degree of application: the methods of sodium alendronate quantitative titrimetric determination in drugs and of 4-aminobutyric acid impurity separation, identification and quantitative determination in sodium alendronate have been introduced and use in Chemical analytical laboratory of quality control department of Corporation "Stoma" (Kharkov).