Spectrofluorimetric determination of amisulpride and bumidazone in raw materials and tablets M. I. Walash, F. Belal, M. M. Tolba and M. I. Halawa* ABSTRACT: A highly sensitive, simple and rapid spectrofluorimetric method was developed for the determination of amisul- pride (AMS) and bumidazone (BUM) in tablet form. The proposed method is based on measuring the native fluorescence of the studied drugs in methanol at 360 and 344 nm after excitation at 276 and 232 nm for AMS and BUM, respectively. The fluorescence–concentration plots were rectilinear over the ranges of 5.0–60.0 ng/mL for AMS and 0.5–5.0 μg/mL for BUM. The lower detection limits were 0.70 ng/mL and 0.06 μg/mL, and the lower quantification limits were 2.0 ng/mL and 0.18 μg/mL for AMS and BUM, respectively. The method was successfully applied for the analysis of AMS and BUM in commercial tablets. Statistical evaluation and comparison of the data obtained using the proposed and comparison methods revealed good accuracy and precision for the proposed method. Copyright © 2014 John Wiley & Sons, Ltd. Keywords: amisulpride; bumidazone; spectrofluorimetry; tablets Introduction Chemically, amisulpride (AMS) is 4-amino-N-{[(2RS)-1-ethylpyr- rolidin-2-yl]methyl}-5(ethyl sulfonyl)-2-methoxybenzamide (Fig. 1a). AMS is a selective D2–D3 antagonist that has been reported to be effective in the treatment of schizophrenia and major depressive disorder (1). AMS has been the subject of monographs in the British Pharmacopoeia (2) and the European Pharmacopoeia (3). Re- viewing the literature revealed that only a few analytical methods have been reported for the determination of AMS including spec- trophotometry (4–9), high-performance liquid chromatography (HPLC) (10–13) and liquid chromatography–mass spectrometry (LC-MS) (14–18). Bumadizone calcium semi-hydrate (BUM) is butylmalonic acid mono-(1,2-diphenylhydrazide) calcium semi- hydrate; (Fig. 1b). It is used as a non-steroidal anti-inflammatory drug and has a peripheral analgesic effect (1). A literature survey revealed that there are only three chromatographic methods for the determination of BUM (19–21). To the best of our knowledge, nothing has been published concerning the specrofluorimetric determination of AMS and BUM in tablet form. The current study aimed to develop and validate a simple, rapid and sensitive spectrofluorimetric method for the determination of AMS and BUM utilizing their native fluorescence in methanol. Experimental Apparatus All fluorescence measurements were made using a RF-1501 Shimadzu spectrofluorometer, equipped with a 150 W xenon arc lamp. Materials and reagents Amisulpride, lot # 2AMS0361011 was kindly provided by Sigma Pharmaceutical Industries, Egypt. Amipride tablets (batch # 11950), labeled as containing 50 mg of AMS, were from of Al-Andalus Medical Company, Cairo, Egypt. Bumadizone calcium semi- hydrate was kindly provided by October Pharma S.A.E. Company (6th October City, Egypt). Octomotol W tablets (batch # B1830212), labeled as containing 110 mg of BUM, were from October Pharma S.A.E. Company, 6th October City, Egypt. Sodium dodecyl sulfate (SDS) solution and cetyl trimethyl ammo- nium bromide (CTAB; 99%) were purchased from Winlab Ltd (Market Harborough, UK). Methanol, acetonitrile and n-propanol were obtained from Sigma-Aldrich (Munich, Germany). Dimethylsulfoxide (DMSO) was purchased from Riedel-de Häen (Seelze, Germany), dimethyl formamide (DMF) was obtained from El-Nasr Pharmaceutical Chemical Co. (ADWIC; Egypt), and hydroxypropyl-β-cyclodextrin (HP-β-CD) was obtained from Merck (Darmstadt, Germany). Tween-80, methyl cellulose, ethanol, glacial acetic acid, so- dium acetate trihydrate and boric acid were all obtained from El-Nasr Pharmaceutical Chemical Co. SDS, CTAB, methylcellulose, HP-β-CD and Tween-80 were pre- pared as 0.1% w/v aqueous solutions, acetate buffer (pH 3.0–5.5) and borate buffer (pH 6.0–10.0) solutions were freshly prepared. Standard solutions Stock solutions equivalent to 100.0 μg/mL of AMS and BUM were prepared by dissolving 10 mg of each in 100 mL of methanol with the aid of an ultrasonic bath. Working standard solutions of 1.0 μg/mL for AMS and 10.0 μg/mL for BUM were prepared by appropriate dilution of the stock solutions with methanol. * Correspondence to: M. Halawa, Department of Analytical Chemistry, Faculty of Pharmacy, University of Mansoura, 35516, Mansoura, Egypt. E-mail: m_halawa88@hotmail.com Department of Analytical Chemistry, University of Mansour, Mansour, Egypt Luminescence 2014 Copyright © 2014 John Wiley & Sons, Ltd. Short communication Received: 3 November 2013, Revised: 18 February 2014, Accepted: 25 February 2014 Published online in Wiley Online Library (wileyonlinelibrary.com) DOI 10.1002/bio.2673