Available online www.jocpr.com Journal of Chemical and Pharmaceutical Research, 2012, 4(10):4462-4467 Research Article ISSN : 0975-7384 CODEN(USA) : JCPRC5 4462 Simultaneous Determination of Moxifloxacin Hydrochloride and Dexamethasone Sodium Phosphate in Eye Drops by HPLC and Absorbance Correction Method M J Dabhi a , A H Patwari a , U H Desai a , D B Doshi a , I S Rathod a and B N Suhagia b a Department of Quality Assurance, L. M. College of Pharmacy, Ahmedabad – 380009, India b Faculty of Pharmacy, D. D. University, Nadiad, India _____________________________________________________________________________________________ ABSTRACT High performance liquid chromatography and Absorbance correction methods were applied for the simultaneous determination of Moxifloxacin hydrochloride and Dexamethasone sodium phosphate in eye drops. Chromatographic separation was achieved on reversed-phase C18 column (25 cm × 4.6 mm id, 5 μm) in the isocratic mode using methanol-water-triethylamine (60:40:0.75, v/v/v; pH adjusted to 3.25 ± 0.05 with orthophosphoric acid) as the mobile phase at a flow rate 0.8 mL/min. Quantitation was achieved with UV detection at 254 nm. In the proposed HPLC method, the concentration range of 5-30 and 1-6 μg/mL, with mean recoveries of 101.46 ± 1.57 and 101.50 ± 1.64 % for moxifloxacin hydrochloride and dexamethasone sodium phosphate respectively was obtained. In the Absorbance correction method, quantification was achieved over the concentration range of 10-50 and 2-10 μg/mL, with mean recoveries of 100.49±0.62and 100.36 ± 1.09% for moxifloxacin hydrochloride and dexamethasone sodium phosphate respectively. Determination was performed at 244.2 nm and 357 nm for moxifloxacin hydrochloride and dexamethasone sodium phosphate. The proposed methods were successfully applied for the analysis of synthetic mixtures and pharmaceutical formulations of moxifloxacin hydrochloride and dexamethasone sodium phosphate without any interference from common excipients. The results obtained by applying the proposed methods were statistically compared by the Student’s t-test. Keywords: Moxifloxacin hydrochloride, Dexamethasone sodium phosphate, High performance liquid chromatography, Absorbance Correction method, Simultaneous determination _____________________________________________________________________________________________ INTRODUCTION Moxifloxacin hydrochloride (MOXI) (1-cyclopropyl-7-((S,S)-2,8-diazabicyclo(4.3.0)non-8-yl]-6-fluoro-8-methoxy- 1,4-dihydro-4-oxo-3-quinoline carboxylic acid) is a broad spectrum antibacterial agent, belonging to the group of fluoroquinolones [1-2]. Moxifloxacin hydrochloride is active against a wide variety of gram-positive and gram- negative organism, use in the treatment of conjunctivitis, chronic bronchitis and community acquired pneumonia [3]. Dexamethasone sodium phosphate (DEXP) (disodium 9α-fluoro-11β,17α-dihydroxy-16α-methyl-3,20-dioxo-1,4- pregna- dien-21-yl phosphate) is a synthetic glucocorticoid with varied pharmacological activities including anti- inflammatory[1-3]. Literature survey reveals that HPLC [3-6], HPTLC [7-10], LC-MS [11-12], Capillary electrophoresis [13] and UV spectroscopy [14] method has been reported for determination of moxifloxacin hydrochloride and dexamethasone sodium phosphate alone or in combination with other drugs in pharmaceutical formulations and in human plasma. Moxifloxacin hydrochloride and dexamethasone sodium phosphate eye drops are not official in any pharmacopoeia. No isocratic HPLC method and spectrophotometric methods are available for simultaneous determination of moxifloxacin hydrochloride and dexamethasone sodium phosphate, so there was a need to develop and validate