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

Abstract

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 × 104 L mol−1 cm−1, 0.13 μg mL−1, 0.43–12.2 μg mL−1, 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 [VO2(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 VO2 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.

Design of resonance Rayleigh scattering and spectrofluorimetric methods for the determination of the antihistaminic drug, hydroxyzine, based on its interaction with 2,4,5,7‐tetraiodofluorescein: Evaluation of analytical eco‐scale and greenness/whiteness algorithms

“…The obtained LOD were 0.047 μg ml −1 and 0.033 μg ml −1 , and the resulting LOQ were 0.143 μg ml −1 and 0.099 μg ml −1 for the spectrofluorimetric and RRS approaches, respectively. In comparison with the values of LOD recorded by spectroscopic methods for determining HXZ pharmaceutical tablets, which were 0.13 μg ml −1 [11], 0.62 μg ml −1 [11], 0.14 μg ml −1 [1], and 0.13 μg ml −1 [12], the proposed spectroscopic methods display superior sensitivity compared to these spectroscopic methods.…”

“…Additionally, HXZ can be used to treat allergic diseases such as histamine-mediated pruritus, atopic dermatitis, chronic urticaria, and contact dermatitis [3]. Varied methodologies include chromatographic (such as HPLC [4][5][6][7] and GC [8]), electrochemical [9,10], and spectrophotometric [1,11,12] methods that have been reported for the quantitation of HXZ. As of yet, there is no reported method for estimating the drug using the spectrofluorimetric technique.…”

Extractive Spectrophotometric Determination and Theoretical Investigations of Two New Vanadium(V) Complexes

“…The next step was to correctly pair each of the two cationic structures ( Figure 11 a,b) with the anion [VO 2 (HTAR)] − optimized in a previous paper [ 23 ] ( Figure 11 c). Two different NTC + –[VO 2 (HTAR)] − structures were constructed and fully optimized at the HF/3–21G theoretical level ( Figure 12 a,b).…”

“…The ground-state equilibrium geometries of the cations, TT + and NTC + , were optimized at the B3LYP/6-311++G** and B3LYP/6-31+G* levels of theory, respectively. Each of these cations was then paired in different ways with the anionic complex [VO 2 (HTAR)] − studied in a previous work [ 23 ] as described above.…”

“…They are often coupled with preconcentration techniques, which can greatly increase their range of application [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. In a previous paper, we described the application of the V(V)—6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR) anionic chelate [VO 2 (HTAR)] − [ 22 ] for the liquid–liquid extraction (LLE)–spectrophotometric determination of hydroxyzine hydrochloride in pharmaceuticals [ 23 ]. In the present paper, we set three goals: To study the LLE of the V(V)–HTAR species in the presence of tetrazolium salt; To find the ground-state equilibrium geometries of the extracted species using quantum chemical calculations at the B3LYP and HF levels of theory; To develop a competitive LLE–spectrophotometric method for determining V(V) in real samples.…”