Romanian Society of Pharmaceutical Sciences

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WATER STRUCTURING EFFECT OF METHANOL AND ETHANOL ON ION PAIRING OF SOME GUANIDIUM CONTAINIG PHARMACEUTICAL SUBSTANCES. ANALYTICAL APPLICATIONS

MARINELA FLOREA1, IOANA CLEMENTINA CONSTANTINESCU1*, ANGELA NEDELCU1, CLAUDIA-MARIA GUȚU2, MAHER ABDULRAZZAQ LUQMAN AL-HAKEEM3, LĂCRĂMIOARA POPA3

”Carol Davila” University of Medicine and Pharmacy, Faculty of Pharmacy, 6 Traian Vuia Street, 020956, Bucharest, Romania
1.Department of Analytical Chemistry
2.Department of Toxicology
3.Department of Physical and Colloidal Chemistry

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The influence of water structuring effect of methanol and ethanol on ion pairing of two guanidinum containing pharmaceutical compounds, namely streptomycin and arginine, was studied. Congo red was used as counterion. For this purpose, the molecular modelling, physico-chemical constants (dielectric constant, conductivity) and absorption and resonance light scattering spectrometry were used. Determinations were performed using water/alcohol binary solvent mixtures containing molar fractions of 0.05 methanol, respectively 0.03 ethanol. The results showed that, in low concentrations, methanol and ethanol favours ion pairing. For streptomycin, analytical applications were studied.