45 Int. J. Pharm. Med. & Bio. Sc. 2013 Kareti Srinivasa Rao et al., 2013 RP-HPLC METHOD FOR THE ESTIMATION OF ZIPRASIDONE Kareti Srinivasa Rao 1* , Nargesh Kumar Keshar 1 , Prasenjit Roy Choudhury 1 , M E Bhanoji Rao 1 and Ajay Kumar Pattnaik 2 Research Paper A simple, sensitive, accurate and precise LC assay method was developed for the quantitative determination of Ziprasidone Hydrochloride (ZSH) in pharmaceutical dosage form. Chromatographic separation was achieved by use of Lichrospher RP-18 column (250 × 4.0 mm, 5 m), using 20 mM ammonium acetate (pH adjusted to 3.0 with orthophosphoric acid) and methanol (30:70 %v/v) as mobile phase at 25 o C. The described method was linear over a range of 1-500 g mL-1 for determination of ZSH (r= 0.9998). F-test and t-test at 95% confidence level were used to check the intermediate precision data obtained under different experimental setups; the calculated value was found to be less than critical value. The developed method was found to be simple, specific, robust, linear, precise, and accurate for the determination of ZSH in pharmaceutical formulations. Keywords: Ziprasidone Hydrochloride, validation, assay, recovery studies. *Corresponding Author: K. Srinivasa Rao,  ksrao108@gmail.com INTRODUCTION Ziprasidone, 5-[2-[4-(1, 2-benzisothiazol-3.2-yl)- 1-piperazinyl] ethyl]-6- chloro-1,3.2-dihydro-2 H - indol-2-one , (ZSH) (Figure 1) is an antipsychotic agent that is chemically unrelated to phenothiazine or butyrophenone antipsychotic agents. ZSH ‘s unique pharmacology offers advantages in the areas of antipsychotic-induced weight gain and possibly the treatment of depressive symptoms in patients with schizophrenia or schizoaffective disorder. The efficacy of ZSH in schizophrenia is primarily attributable to dopamine (i.e, D 2 ) and serotonin (specifically 5HT 2 A) receptor ISSN 2278 – 5221 www.ijpmbs.com Vol. 2, No. 1, January 2013 © 2013 IJPMBS. All Rights Reserved Int. J. Pharm. Med. & Bio. Sc. 2013 1 Roland Institute of Pharmaceutical Sciences, Berhampur -760010, Orissa, India. 2 Khallikote College, Berhampur, Orissa, India. antagonism, which contributes to its more favorable effect on weight gain than clozapine, olanzapine, and risperidone (Sweetman, 2009). Literature survey revealed that several analytical methods were reported for the determination of ZSH in biological matrices, including; liquid chromatography-tandem mass spectrometry (Zhang et al., 2008; Zhang et al., 2007; Zhang et al ., 2007; Al-Dirbashi et al ., 2006), liquid chromatography/UV detection (Zhang et al., 2007), liquid chromatography/fluorescence detection (Suckow et al., 2004). Few analytical