A Validated RP-HPLC Method for the Estimation of Pizotifen in Pharmaceutical Dosage Form

A simple, selective, linear, precise, and accurate RP-HPLC method was developed and validated for rapid assay of Pizotifen in pharmaceutical dosage form. Isocratic elution at a flow rate of 1.0？mL/min was employed on Chromosil C18 (250？mm × 4.6？mm, 5？μm) column at ambient temperature. The mobile phase consists of methanol？:？acetonitrile in the ratio of 10？:？90 v/v. The UV detection wavelength was 230？nm, and 20？μL sample was injected. The retention time for Pizotifen was 2.019？min. The percent RSD for accuracy of the method was found to be 0.2603%. The method was validated as per the ICH guidelines. The method can be successfully applied for routine analysis of Pizotifen in the rapid and reliable determination of Pizotifen in pharmaceutical dosage form. 1. Introduction Pizotifen (4-(1-methyl-4-piperidylidine)-9,10-dihydro-4H-benzo- cyclohepta -thiophene); Figure 1(a)) is a benzocycloheptene-based drug used for the prevention of vascular headache including migraine and cluster headache. Alternatively used instead of propanolol, topiramate, valproic acid, and amitriptyline. Pizotifen is reasonably effective, but its use is limited by side effects, principally drowsiness and weight gain, and it is usually not the first-choice medicine for preventing migraines, instead it is used as an alternative when other drugs have failed to be effective [1–3]. Pizotifen is also used as antidepressant or for the treatment of anxiety or social phobia. Animal studies also suggest that pizotifen could be used in the treatment of serotonin syndrome or MDMA overdose in a similar manner to the closely related antihistamine/antiserotonin drug cyproheptadine [4–6]. Pizotifen is contraindicated in gastric outlet obstruction, pregnancy, angle-closure glaucoma, and difficulty in urination [6–8]. Figure 1: (a) Structure of Pizotifen. (b) RP-HPLC Chromatogram of standard solution (c) On x-axis: concentration of sample solution, on y-axis: peak area response. Abounassif et al. [9] reported the stability-indicating methods and validated through a study of UV-degraded solutions contained in quartz cells. RP-HPLC liquid chromatographic method for quantification of Pizotifen malate in pharmaceutical solid dosage forms was reported by Rahman et al. [10]. Here we with reporting precise and accurate RP-HPLC method developed and validated for rapid assay of Pizotifen in pharmaceutical dosage forms. 2. Materials and Methods 2.1. Chemicals and Reagents The reference sample of Pizotifen (API) was obtained from V.V MED, Hyderabad. The Formulation was procured from the local market. acetonitrile,