J. Mex. Chem. Soc. 2010, 54(4), 233-239 ArticleSensitive and Selective Extractive Spectrophotometric Method for the Determination of Hydroxyzine Dihydrochloride© 2010, Sociedad in Pharmaceuticals Química de México 233 ISSN 1870-249X Sensitive and Selective Extractive Spectrophotometric Method for the Determination of Hydroxyzine Dihydrochloride in Pharmaceuticals Nagaraju Rajendraprasad, Kanakapura Basavaiah,* Kanakapura Basavaiah Vinay and Hosakere Doddarevanna Revanasiddappa Department of Studies in Chemistry, Manasagangothri, University of Mysore, Mysore 570 006, India. e-mail: basavaiahk@ yahoo.co.in Received June 17, 2010; accepted September 10, 2010 Abstract. Hydroxyzine dihydrochloride (HDH), a piperazine H1- Resumen. El dihidrocloruro de hidroxicina (HDH), una piperazina receptor antagonist and antihistamine, is a rapid acting anxiolytic antagonista del receptor H1 y un antihistamínico, es un ansiolítico de used principally as an anti-emetic. A sensitive, selective, and precise acción rápida usado principalmente como anti-emético. Se desarrolló and accurate spectrophotometric method based on the formation of y validó un método espectrofotométrico sensible, selectivo, preciso y an ion-pair with orange II (ORG II) as ion-pair complexing agent exacto basado en la formación de un par iónico con naranja II (ORG was developed and validated for the determination of HDH in phar- II) como un agente complejante para la determinación de HDH en maceuticals. The chloroform-extractable ion-pair complex exhibited productos farmacéuticos. El par iónico extraído en cloroformo exhi- an absorption maximum at 480 nm. Optimization of different experi- bió un máximo de absorción a 480 nm. Se describió la optimización mental conditions is described. Beer’s law is obeyed in the range of de las diferentes condiciones experimentales. La ley de Beer se obe- 1.5-15 µg mL-1 with an apparent molar absorptivity value of 2.07 × deció en el intervalo de 1.5-15 µg mL-1 con un valor de absortividad 104 L mol-1 cm-1 and Sandell’s sensitivity value of 0.0216 µg cm- molar aparente de 2.07 × 104 L mol-1 cm-1 y un valor de sensibilidad 2. The limit of detection (LOD) and limit of quantification (LOQ) de Sandell de 0.0216 µg cm-2. El límite de detección (LD) y el límite -1 -1 are 0.14 and 0.41 µg mL , respectively. A Job’s plot of absorbance de cuantificación (LC) son 0.14 y 0.41 µg mL , respectivamente. versus molar ratio of HDH to ORG II indicated (1:2) stoichiometric Una gráfica de Job de absorbancia versus relación molar de HDH y ratio. Within- and between-day relative standard deviations at three ORG II indicó una relación estequiométrica (1:2). Las desviaciones different concentration levels were < 3%. The developed method was estándar relativas dentro y entre días, a tres diferentes niveles de successfully applied to commercial tablets. The results obtained were concentración, fueron < 3%. El método desarrollado fue aplicado exi- in good agreement with those obtained using the official method. tosamente a tabletas comerciales. Los resultados obtenidos estuvieron No interference was encountered from co-formulated substances. en buena concordancia con los obtenidos con el método oficial. No se Recoveries were 96-109 %. encontró ninguna interferencia de parte de las sustancias de la formu- Keywords: Spectrophotometry, hydroxyzine, orange II, pharmaceu- lación. Las recuperaciones fueron de 96-109 %. ticals. Palabras clave: Espectrofotometría, hidroxicina, naranja II, produc- tos farmacéuticos. Introduction decrease in the absorbance of Hg(II)-diphenylcarbazone com- plex, consequent to the replacement of diphenylcarbazone of Hydroxyzine dihydrochloride (HDH), chemically known as the complex by the chloride of the drug, was measured at 540 2-[2-[4-[(4-chlorophenyl)phenymethyl]-1-piperazinyl]ethoxy nm and the method is applicable in the range 0-60 µg mL-1. ]ethanol, dihydrochloride, is a piperazine H1-antagonist with Sane et al [24] have used 3 dyes for the determination of the sedative properties. It is widely used in the control of anxiety drug content in pharmaceuticals. Kurzawa et al [25] employed [1] and also used principally as an anti-emetic [2, 3]. the spectrophotometric procedure for HDH by using reinecke A variety of analytical techniques such as high-perfor- salt. One of the present authors has also reported a method mance liquid chromatography [4-8], gas chromatography [9], based on the charge transfer complex formation reaction with thin layer chromatography [10], micellar liquid chromatog- chloranilic acid [26] in acetonitrile. raphy [11], capillary zone electrophoresis [3], voltammetry The reported visible spectrophotometric methods though [12], LC-MS [13], potentiometry [14, 15], gravimetry [16] and seem simple, they are less sensitive [18, 26], some are criti- titrimetry [17-22] have been reported for the determination cally dependent on pH [24] and the reaction products either of HDH in biological fluids and pharmaceuticals. The offi- require long time to form or less stable [25] (Table 1). cial USP method available for the assay of the drug in tablets The present work describes a simple, sensitive and selec- employs a chromatographic system equipped with a UV-detec- tive spectrophotometric method for the determination of HDH tor, where HDH can be detected at 232 nm [23]. in pharmaceuticals. The method is based on the measurement In the literature, four visible spectrophotometric methods of the red coloured chloroform extractable ion-pair complex [18, 24-26] are found for the quantitative determination of HDH formed between HDH and ORG II in H2SO4 medium. The in pharmaceuticals. In the method reported by Basavaiah and HDH-ORG II ion-pair complex is highly stable and the ion- Charan [18], to a fixed concentration of Hg(II)-diphenylcar- pair formed and extracted in acid medium without requiring bazone complex different amounts of drug were added and the rigid pH control. 234 J. Mex. Chem. Soc. 2010, 54(4) Nagaraju Rajendraprasad et al. Table 1. Comparison of the performance characteristics of the proposed method with reported visible spectrophotometric methods. Sí. Reagent/s used Methodology λmax (nm) Linear range LOD (µg Remarks Ref No. (µg mL-1) mL-1) (ε in L mol-1 cm-1) 1 Hg(II)- Decrease in the 540 0-60 NA Less sensitive 18 diphenylcarbazone absorbance of Hg(II)- (6.62 × 103) diphenylcarbazone complex measured 2 Three dyes Measurement of 410 — NA Ion-pair formation 24 absorbance of ion-pair and extraction entirely complex depends on pH 3 Reinecke salt Absorbance of 525.5 30-525 NA The procedure tedious 25 hydroxyzine- (1.27 × 105) and time consuming reineckate complex in which the drug is measured precipitated as Reinecke salt, filtered, dried at 60 °C for 6 h and then dissolved in acetone before measuring the absorbance 4 Chloranilic acid- Absorbance of charge- 535 25-150 1.25 Less sensitive 26 acetonitrile, transfer complex (1.37 × 103) ammonia measured 5 ORG II-CHCl3 Absorbance of HDH- 480 1.5-15 0.14 Highly sensitive, Present work ORG II ion-pair (2.07 × 104) applicable for wide complex measured linear dynamic range, Highly stable coloured product ε. Molar absorptivity; NA. Not available. Results and discussions Hydroxyzine, as a positively charged amino compound in acid medium, forms chloroform extractable red colored ion- Ion-pair extractive spectrophotometry has gained great atten- pair complex with the anionic dye ORG II and the resulting tion for the pharmaceutically important compounds [27-31]. red colored species shows an absorption maxima at 480 nm Due to the sulfonate anionic group present in the dye, ORG II, (Fig 1). The structures of the protonated HDH, ORG II and there is a strong tendency to form the complex with the coun- HDH-ORG II ion-pair complex are shown in scheme 1. ter cations as ion-pair complex. HO HO O + O O O Na S H Cl Cl + O N N + N A N N HCl H 2 Cl HCl N OH iii) i) ii) HO O O O S H Cl + O N B + N N . 2 H N OH iv) Scheme 1. Structures of i) HDH; ii) protonated HDH; iii) ORG II and Fig. 1. Absorption spectra of: A. ion-pair complex (9.0 µg mL-1 iv) HDH-ORG II ion-pair complex. HDH); B. blank. Sensitive and Selective Extractive Spectrophotometric Method for the Determination of Hydroxyzine Dihydrochloride in Pharmaceuticals 235 In order to establish optimum conditions necessary for solution and the ion-pair was extracted with 10 mL of CHCl3. rapid and quantitative formation of coloured product with The study revealed that, minimum blank absorbance and maxi- maximum stability and sensitivity, control experiments were mum complex absorbance values were obtained with clear performed by measuring the absorbance at 480 nm by varying separation of organic and aqueous layers when the volume of one and fixing the other parameters. water in the aqueous phase was maintained at > 20 mL. Hence, an aqueous phase volume of 30 mL was used in all subsequent work. Method development: Optimization of experimental variables Choice of organic solvent. It was found that the ion-pair com- plex was readily and quantitatively extractable in chloroform. In chloroform reproducible and precise results were obtained. Effect of concentration of sulphuric acid. Effect of H2SO4 concentration of the aqueous solution on the formation and Therefore chloroform was used as extracting solvent. extraction of the HDH-ORG II ion-pair was studied by vary- ing the concentration of the acid in the range 0.0333-0.333 M Reaction time. After the addition of dye, the effect of standing (1-5 mL of 2 M acid in a total volume of 30 mL) keeping all time was studied in the time range 5-30 min before extraction. other variables constant (5 mL of 30 µg mL-1 HDH, 20 mL After a contact time of 5 min, measured absorbance of the water and 5 mL dye solution), and it was found that maximum complex after extraction into chloroform, showed almost con- and constant absorbance readings were obtained in the range stant from 5-30 min.