Vanadium-Containing Anionic Chelate for Spectrophotometric Determination of Hydroxyzine Hydrochloride in Pharmaceuticals

• Published in: Molecules (Basel, Switzerland) Vol. 28; no. 6; p. 2484
• Main Authors: Kirova, Gergana Kirilova, Velkova, Zdravka Yancheva, Delchev, Vassil Borisov, Gavazov, Kiril Blazhev
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01-03-2023; MDPI
• Subjects: 6-hexyl-4-(2-thiazolylazo)resorcinol; Absorptivity; Antihistamines; Azo dyes; Basis functions; Care and treatment; Cations; Chromatography; Equilibrium; Histamine; Hydrogen bonds; Hydroxyzine; Indicators and Reagents; Ion association; Ligands; Liquid-liquid extraction; Pharmaceutical Preparations; Pharmaceuticals; Reagents; Resorcinol; Skin diseases; spectrophotometric determination; Spectrophotometry; Surface active agents; Vanadium; Vanadium - chemistry; Vanadium oxides; vanadium(V); Bulgaria; pharmaceutical dosage forms; vanadium(V); 6-hexyl-4-(2-thiazolylazo)resorcinol; spectrophotometric determination; ion association; liquid–liquid extraction; hydroxyzine; DFT calculations
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules28062484

Four azo dyes known to form anionic complexes with V(V) were investigated as potential liquid-liquid extraction-spectrophotometric reagents for the antihistamine medication hydroxyzine hydrochloride (HZH). A stable ion-association complex suitable for analytical purposes was obtained with 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR). The molar absorption coefficient, limit of detection, linear working range, and relative standard deviation in the analysis of real pharmaceutical samples (tablets and syrup) were 3.50 × 10
L mol
cm
, 0.13 μg mL
, 0.43-12.2 μg mL
, and ≤2.7%, respectively. After elucidating the molar ratio in the extracted ion-association complex (HZH:V = 1:1), the ground-state equilibrium geometries of the two constituent ions-HZH
and [VO
(HTAR)]
-were optimized at the B3LYP level of theory using 6-311++G** basis functions. The cation and anion were then paired in four different ways to find the most likely structure of the extracted species. In the lowest-energy structure, the VO
group interacts predominantly with the heterochain of the cation. A hydrogen bond is present (V-O···H-O; 1.714 Å) involving the terminal oxygen of this chain.