In vitro study of the interaction of cysteine with a thiazide diuretic (hydrochlorothiazide) at different ph by voltammetric and spectroscopic techniques

Biçer E., Ozdemir N.

RUSSIAN JOURNAL OF ELECTROCHEMISTRY, vol.49, no.10, pp.948-954, 2013 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 49 Issue: 10
  • Publication Date: 2013
  • Doi Number: 10.1134/s1023193513100042
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.948-954
  • Keywords: cysteine, hydrochlorothiazide, drug-amino acid interaction, pH effect, voltammetry, absorption spectroscopy, GYRASE-B PROTEIN, COUMARIN DRUGS, SERUM-ALBUMIN, DNA, BINDING, ACID, POLAROGRAPHY, COMPLEXES, ELECTRODE, HEALTHY
  • Ondokuz Mayıs University Affiliated: Yes


The interaction of cysteine (RSH) with a thiazide diuretic, hydrochlorothiazide (HCTZ) was characterized by UV-Vis absorption spectroscopy and square-wave voltammetry in Britton-Robinson (B-R) buffer solution (with pH 5, 7 and 9). On the square-wave voltamogram of cysteine, the reduction peak current of mercurous cysteine thiolate (Hg-2(RS)(2)) decreased and its peak potential shifted to more positive values with the addition of HCTZ. This results showed that the RSH interacted with HCTZ. The stoichiometry of HCTZ-RSH molecular complex was determined by voltammetric data with the result of 1: 1. By using linear regression analysis of the voltammetric data at pH 5, 7 and 9, the apparent formation constants of HCTZ-RSH complex were calculated to be 9.54 x 10(3), 2.80 x 10(4) and 2.55 x 10(4) M-1, respectively. At the same time, this interaction was also supported by UV-Vis spectroscopic measurements. According to the voltammetric and spectroscopic results, it was suggested that the interaction mode between RSH and HCTZ molecules might be a combination of hydrophobic interactions and hydrogen bonds.