Open Science Journal of Pharmacy and Pharmacology 2017; 5(3): 12-18 http://www.openscienceonline.com/journal/osjpp Liquid Chromatographic and Potentiometric Methods for the Determination of Oxomemazine in Pharmaceutical Preparations Mohamed Alaa Fathy Elmosallamy 1 , Amr Lotfy Saber 1, 3, * , Alaa Said Amin 2 , Hamada Mohammed Ahmed Killa 1 1 Department of Chemistry, Faculty of Science, Zagazig University, Zagazig, Egypt 2 Department of Chemistry, Faculty of Science, Benha University, Benha, Egypt 3 Department of Chemistry, Faculty of Science, Umm Al Qura University, Makkah, Saudi Arabia Email address alshefny@yahoo.com (A. L. Saber) * Corresponding author To cite this article Mohamed Alaa Fathy Elmosallamy, Amr Lotfy Saber, Alaa Said Amin, Hamada Mohammed Ahmed Killa. Liquid Chromatographic and Potentiometric Methods for the Determination of Oxomemazine in Pharmaceutical Preparations. Open Science Journal of Pharmacy and Pharmacology. Vol. 5, No. 3, 2017, pp. 12-18. Received: March 29, 2017; Accepted: April 27, 2017; Published: August 15 2017 Abstract Simple and selective two different techniques are developed for the determination of oxomemazine in pharmaceutical preparations. A rapid (less than 6 min) and accurate high performance liquid chromatography(HPLC) method has been developed where chromatographic analysis is performed on Nova-Pak ® C 18 column (3.9 mm × 150 mm, 5 µm) with an ammonium formate buffer adjusted with formic acid to pH 3.0 and acetonitrile (75: 25, v/v) as a mobile phase, and detection at 235 nm. Good linearity (0.99, r 2 ), accuracy (≥ 99.20%), and precision (≤ 0.6 RSD) were obtained. Potentiometric measurements are based on tetrakis (p-chlorophenyl) borate-oxomemazine ion-pair complex as an electroactive species incorporating in a plasticized poly vinyl chloride (PVC) membrane with o-nitrophenyl octyl ether (o-NPOE) or dioctyl phthalate (DOP). The sensor exhibits fast and stable Nernstian response for oxomemazine over the concentration range of 1.0 × 10 -5 – 1.0 × 10 -2 mol L -1 and pH range of 3.5 - 6.0. The sensor shows reasonable selectivity towards oxomemazine hydrochloride over many cations. No significant interferences are caused by drug excipients and diluents. Results with an average recovery of 100.6% and a mean standard deviation of 0.77% of the nominal were obtained. Keywords HPLC, Potentiometry, Oxomemazine Hydrochloride, Pharmaceutical Preparations 1. Introduction Oxomemazine, a phenothiazine derivative, is an antihistamine used for the symptomatic relief of hypersensitivity reaction. It is also an ingredient of compound preparations for the symptomatic treatment of coughs and the common cold. It is given orally in doses equivalent to 10 to 40 mg of oxomemazine daily. Oxomemazine may also be administered rectally in form of suppositories. Oxomemazine hydrochloride (OXO-HCl) has been used similarly by mouth. It is chemically known as N,N,β-trimethyl-3-(10H-phenothiazin-10-yl)-propan-1- amine-5,5-dioxide [1] (Figure 1). S N O O N Figure 1. Chemical structure of oxomemazine.