Extractive Spectrophotometric Assay of Cyclizine in a Pharmaceutical Formulation and Biological ﬂuids

Saudi Pharmaceutical Journal (2012) 20, 255–262 King Saud University Saudi Pharmaceutical Journal www.ksu.edu.sa www.sciencedirect.com ORIGINAL ARTICLE Extractive spectrophotometric assay of cyclizine in a pharmaceutical formulation and biological fluids Nora Hamad Al-Shaalan * Chemistry Department, Faculty of Science, Princess Nora Bint Abdul Rahman University, P.O. Box 240549, Riyadh 11322, Saudi Arabia Received 29 January 2012; accepted 14 February 2012 Available online 21 February 2012 KEYWORDS Abstract Two highly sensitive and simple spectrophotometric methods were developed to quanti- Spectrophotometry; tate the drug cyclizine (CYC) in its pure form and in a pharmaceutical formulation. The two methods Cyclizine; involved ion-associate formation reactions (method A) with mono-acid azo dyes, i.e., sudan (I) and Valoid; sudan (II), as well as ion-pair reactions (method B) with bi-azo dyes, i.e., sudan (III), sudan (IV) and Sudan dye sudan red 7B (V). The reactions were extracted with chloroform, and the extraction products were quantitatively measured at 480, 550, 500, 530 and 570 nm using reagents I–V, respectively. The reac- tion conditions were monitored and optimised. The Beer plots for reagents I–V showed linear rela- tionships for the concentrations of 4.2–52.0, 5.4–96.0, 3.5–43.0, 4.4–80.0 and 0.6–18.0 lgmLÀ1, respectively, with molar absorptivities of 2.2 · 104, 4.1 · 104, 3.6 · 104, 2.5 · 104 and 1.3 · 104 L molÀ1 cmÀ1, respectively. Sandell sensitivities and detection limits were calculated and analysed. The implementation of the two methods to the analysis of a commercial tablet (Valoid) suc- ceeded, and the recovery study suggested that there was no interference from common excipients in the tablet. Regarding the accuracy and precision of the methods, a statistical comparison of the results was performed using Student’s t-test and the F-test at the 95% confidence level. The accuracy and precision of the proposed methods were not significantly different. ª 2012 King Saud University. Production and hosting by Elsevier B.V. All rights reserved. 1. Introduction * Tel.: +966 18244305, mobile: +966 503167512. Cyclizine (CYC) (Scheme 1), 1-(diphenylmethyl)-4-methylpi- E-mail address: [email protected] perazine or 1-benzhydryl-4-methylpiperazine (Benezra, 1977), is a piperazine derivative that has been used effectively for 1319-0164 ª 2012 King Saud University. Production and hosting by the prevention and treatment of nausea and vomiting associ- Elsevier B.V. All rights reserved. ated with motion sickness (Chinn et al., 1952; Dundee and Jones, 1968). The synthesis of cyclizine was reported by Baltzly Peer review under responsibility of King Saud University. et al. (1949). Its anti-histaminic action was discovered by doi:10.1016/j.jsps.2012.02.002 Castillo et al. (1949), and it was reported to be 1/4 as active as its congener, chlorcyclizine, in blocking the histamine- Production and hosting by Elsevier induced spasm of the tracheal chain preparation. The use of cyclizine hydrochloride for the prevention of seasickness and 256 N.H. Al-Shaalan matched quartz cell and operated with a scanning rate of 200 nm minÀ1 and a bandwidth of 2.0 nm. 2.3. Stocks solutions and standards Stock solutions (3 · 10À3 M) of azo dyes were prepared by dis- solving an accurately weighed amount of pure solid in 50 mL of ethanol. These solutions were stable for several months. A standard stock solution of cyclizine (1 mg mLÀ1) was Scheme 1 Cyclizine. prepared in water. The solution was protected from light using aluminium foil and stored at 4 °C. The prepared drug solution airsickness has been described by Chinn et al. (1952, 1953). was stable for 5 days at ambient temperature. Gutner et al. (1954) published methods for the quantitation of cyclizine in dosage forms, including colorimetry (Sane and 2.4. General procedures for the quantitation of CYC Vaidya, 1979), potentiometry (Campbell and Demetriou, 1980), second derivative UV spectrophotometry (Davidson 2.4.1. Method A (mono-azo dyes) and Hassan, 1984; El-Gindy et al., 2004), LC–MS/MS (Jensen A volume equivalent to 2 mg of CYC was transferred to a et al., 2011, HPLC (Low et al., 1983; Jalal et al., 1988; Jonczyk, 50 mL separatory funnel. Two millilitre of 0.5 N HCl and 1999) and capillary zone electrophoresis (Mohammadi et al., 1.5 mL of 3 · 10À3 MIor3mLof3· 10À3 M II were added, 2004). Azo dyes are of interest because of their chromophoric and double-distilled water was added to a final volume of nature and the bidentate character of their ortho-phenolic hy- 10 mL. The produced ion-associates were extracted by shaking droxyl groups. These properties have made azo dyes useful for for 5 min with 5 mL of chloroform. The extraction process was metal complexation studies (Kupleskaya et al., 1988) and for performed three times using three separate additions (5 mL spectroscopic measurements of cation concentrations (Barek each) of chloroform. Each time, the mixture was left to sepa- et al., 1982). rate into two phases. The four extracts were combined in a Chromatographic methods for the determination of cycli- 25 mL volumetric flask, and the absorbance at 480 nm (for I) zine concentrations require an automated system not available or 550 nm (for II) was measured against a blank sample pre- in many research laboratories. Therefore, it was considered pared in the same way. All the measurements were performed worthwhile to develop rapid and sensitive methods suitable at room temperature (25 ± 1 °C) (Scheme 3). for the routine quality control analysis of the investigated drug. Spectrophotometry is still the most frequently used ana- 2.4.2. Method B (bi-azo dyes) lytical technique for pharmaceutical analysis, providing practi- A volume equivalent to 3 mg of CYC was transferred into a cal and significant economic advantages compared to other 50 mL separatory funnel. Two millilitre of 0.5 N HCl and 2, methods. Therefore, I investigated new spectrophotometric 2 and 3 mL of 3 · 10À3 M III, IV and V, respectively, were methods for the quantitation of cyclizine in its pure form added, and double-distilled water was then added to a final and in pharmaceutical formulations. This method is based volume of 10 mL. The produced ion-pairs were extracted by on the formation of ion-associate and ion-pair complexes with shaking for 5 min with 5 mL of chloroform. The extraction mono- and bi-acid azo dyes. process was repeated with another 10 mL aliquot of chloroform. The mixture was left to separate into two phases. The 2. Materials and methods two extracts were combined in a 25 mL calibrated measuring flask, and the absorbance at 500 nm (III), 530 nm (IV) or 2.1. Materials 570 nm (V) was measured against a blank sample prepared in the same way. All the measurements were performed at Cyclizine was purchased from Sigma–Aldrich (St. Louis, MO, room temperature (25 ± 1 °C) (Scheme 4). USA). ValoidÒ (Amdipharm, UK) tablets contained 50 mg of cyclizine hydrochloride. Double-distilled water was used 2.5. Procedure for the pharmaceutical preparation throughout the study. Sudan (I), sudan (II), sudan (III), sudan (IV) and sudan red 7B (V) were obtained from Sigma–Aldrich. Five tablets (Valoid, 50 mg/tablet) were weighed and ground The structures of these dyes are shown in Scheme 2. into a powder. Powder corresponding to 50 mg of the drug was weighed and dissolved in 0.1 N HCl and then transferred À1 2.2. Equipment to a 50 mL volumetric flask to make a solution of 1000 g mL . Using the same acid, the solution was diluted to a final volume Absorption spectra were measured using a Shimadzu UV-1601 of 50 mL, mixed, filtered and then analysed according to meth- (UV–visible) spectrophotometer equipped with a 10 mm od A or B. Scheme 2 Sudan (I). Scheme 3 Sudan (II). Extractive spectrophotometric assay of cyclizine in a pharmaceutical formulation and biological fluids 257 Scheme 4 Sudan (III). Scheme 6 Sudan red 7B (V). 2.6. Procedure for spiked human serum ion-associates (Kf) was determined by substituting the data obtained from the continuous variation in an equation derived The appropriate amounts of standard solutions of CYC were for calculating the stability constant spectrophotometrically added to 1 mL of plasma sample. One millilitre of 10% (w/v) (Inczedy, 1976) (Scheme 6). trichloro-acetic acid was added for each mL of the plasma for nþ1 n n deproteination. The sample was centrifuged at 3500 rpm for Kf ¼ðA=AmÞ½1 À A=Am C n ð1Þ 10 min. Two millilitres of protein-free supernatant was transferred into 10 mL volumetric flask and the above procedure where A is the maximum absorbance obtained from the Job was then followed (Walash et al., 2003). continuous variation curve, Am is the absorbance corresponding to the intersection between the two tangents of the contin- 2.7. Procedure for spiked human urine samples uous variation curve, C is the concentration corresponding to the maximum absorbance, and n is the drug ratio in the reac- Ten millilitres of CYC free urine taken in a 125 mL separating tion product. funnel was spiked with 10 mL of aqueous solution containing 2.5 mg of pure CYC and to the same solution, 5 mL of carbon- 3. Results and discussion ate–bicarbonate buffer of pH 9.5 was added followed by 20 mL of ethylacetate, shaken well for about 15 min and the Nitrogenous drugs are predominantly positively charged in upper organic layer was collected in a beaker containing anhy- slightly acidic solutions. Electronic resonance and steric effects drous sodium sulphate.

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