Demiralay E Ç et al. / Pharmacie Globale (IJCP) 2011, 6 (09) 1 Pharmacie Globale © (IJCP), Vol. 02, Issue 06 Available online at www.pharmacie-globale.info PHARMACIE GLOBALE INTERNATIONAL JOURNAL OF COMPREHENSIVE PHARMACY VALIDATION OF METHOD FOR SIMULTANEOUS DETERMINATION OF PARACETAMOL AND PHENYLEPHRINE IN PHARMACEUTICAL FORMULATION BY REVERSED PHASE LIQUID CHROMATOGRAPHY Ebru Çubuk Demiralay* 1 , Mehmet Gümüştaş 2 and Hale Canbay 3 1 Department of Chemistry, Faculty of Science and Literature, Süleyman Demirel University, 32260 Isparta, Turkey. 2 Department of Chemistry, Faculty of Science and Literature, Hitit University, 19040, Çorum, Turkey. 3 Süleyman Demirel University Experimental and Observational Student Practice and Research Centre, Isparta, Turkey. Received: 6 April 2010; Revised: 22 May 2011; Accepted: 30 May 2011; Available online: 5 June 2011 INTRODUCTION Paracetamol is also known as acetaminophen (N-acetyl- paminophenol, 4-acetamidophenol); it is a major ingredient in numerous cold and flu medications and many prescription analgesics. Paracetamol, unlike other common analgesics such as aspirin and ibuprofen, has no anti-inflammatory properties, and so it is not a member of the class of drugs known as non-steroidal anti- inflammatory drugs or NSAIDs. 1 Phenylephrine hydrochloride chemically, (1R)-1-(3hydroxy-phenyl)-2- (methylamino) ethanol hydrochloride is used as a sympathomimetic amine with mainly direct effects on adrenergic receptors antagonist (antihistaminic). 2 Recently, there has been a dramatic increase in the number of improved reversed phase columns available to the chromatographer, including different functionalities to solve classical problems in pharmaceutical analysis. One of these problems is the analysis of pharmaceutical formulations against the common cold. These preparations usually contain active compounds which have very different polarities. Therefore, chromatographic behaviour of these compounds is different. The key problem in the separation was phenylephrine hydrochloride coeluted with saccharine and/or with paracetamol at acidic pH values. A common combination contains paracetamol (acetaminophen) as the main component and small amounts of phenylephrine. *Corresponding Author: Ebru Çubuk Demiralay Department of Chemistry, Faculty of Science and Literature, Süleyman Demirel University, 32260 Isparta, Turkey. Contact no: +90-246 211 41 67 Email: ebrucubuk@mynet.com.tr, ebrucubuk@sdu.edu.tr Therefore, it is very important to strictly control the amounts of the compounds during preparation of this medicine and a rapid selective analytical method is required. 3,4 Optimization of the chromatographic resolution of ionogenic compounds in reversed phase chromatographic techniques has been actively researched. 5-7 Because of the specific ionization characteristics of these solutes, the two most useful optimization parameters are the pH and organic modifier content of the mobile phase. For ionisable compounds, since changes in solvent content of mobile phase affect the retention behaviour, optimisation of the separation of these mixtures is often carried out at fixed pH. Numerous reversed phase liquid chromatography method is reported for determination of these drugs alone as well as in combination with other drugs in pharmaceutical dosage forms. 8-15 But, phenyl column was not used for separation of these compounds. This study focuses mainly on the organic modifier effect of the mobile phase on the chromatographic behaviour of paracetamol and phenylephrine by using phenyl column. Furthermore, a liquid chromatographic method for the simultaneous determination of these compounds in pediatric cough-cold syrup has been developed. Throught the study the pH of the mobile phase was kept constant at 4.50. The concentration of phosphoric acid was kept constant at 65 mM. The experimental region was selected in such a way that the capacity factors of paracetamol and phenylephrine would stay within the limits 1<k<10. In addition, selectivity ȋαȌ and resolution ȋR s ) values were used in order to establish a general model relating elution ABSTRACT Paracetamol and phenylephrine are frequently associated in pharmaceutical formulations against the common cold. In this work, the proportion of organic modifier of acetonitrile–water mixtures used as mobile phases were optimized in order to separate the paracetamol (acetaminophen) and phenylephrine. The separation was accomplished using a Synergi Polar RP ȋͶ μm, ͳͷͲ x 4, 6 mm I.D.) column. The best chromatographic separation was achieved and acetonitrile-water at 5: 95, % v/v, containing 65 mM phosphoric acid. The developed method was proposed for the simultaneous separation of these drug active compounds in liquid dosage form. Intra- and inter-day repeatabilities evaluated at two different drug concentrations (10-ʹͷ μg/mL for phenylephrine hydrochloride, 150- ͷͲͲ μg/mL for paracetamolȌ. The drug amounts found in the analysis of commercialised preparation agreed with those declared by the manufacturer. Keywords: Optimization, RPLC, Liquid Dosage Form, Paracetamol, Separation. Research Article ISSN 0976-8157