Available online at www.scholarsresearchlibrary.com Scholars Research Library Archives of Applied Science Research, 2010, 2 (4): 103-110 (http://scholarsresearchlibrary.com/archive.html) ISSN 0975-508X CODEN (USA) AASRC9 103 Scholar Research Library Bioequivalence study and bioanalytical method development of Levofloxacin tablets in albino rat plasma using RP-HPLC method Joghee Gowder Dharuman 1 , Aiyalu Rajasekaran 1 , Kullampalayam Krishnasamy Sivakumar 2 , M. Thiagarajan 1 and Arumugam Somasundaram* 3 1 Department of Pharmaceutical Analysis, KMCH College of Pharmacy, Coimbatore, Tamilnadu, India 2 Department of Pharmaceutical Chemistry, KMCH College of Pharmacy, Coimbatore, Tamilnadu, India 3 Department of Pharmacology, KMCH College of Pharmacy, Coimbatore, Tamilnadu, India ______________________________________________________________________________ ABSTRACT A rapid, sensitive and selective HPLC method for the determination of levofloxacin in rat plasma is developed and validated. Separation is done on a Phenomenex C18 RP column with a mobile phase of acetonitrile – 0.4 % triethylamine (pH 3.1) in the ratio of 18:82 % v/v and detection at 295 nm. The standard curve is linear (r > 0.998) over the concentration range of 20.0–5000 ng/ml. The lower limit of quantification (LOD) for levofloxacin is 10.0 ng/ml. The maximum concentration (C max ) obtained for two brands Levoflox and Generic formulation are 132.72 and 113.97 ng/ml respectively. The half life (t 1/2 ) of levofloxacin for Levoflox and Generic are calculated as 1.763 and 1.628 h. Area under the curve t AUC . 0 of Levoflox and Generic is calculated as 271.18 and 279.84 ng h/ml and ∞ t AUC is calculated to be 4.31 and 10.97 ng h/ml respectively and ∞ 0 AUC is calculated to be 275.48 and 290.81 ng h/ml. Elimination rate constant (k el ) is calculated for Levoflox and Generic from the slope of log concentration versus time curve with regression analysis. Elimination rate constant is found to be 0.393 and 0.4272 h -1 . This study shows that there is no significant difference in kinetic parameters between two products. So the two formulations are considered to be bioequivalent. Key words: RP-HPLC, Levofloxacin, bioequivalence. ______________________________________________________________________________