SIMULTANEOUS ESTIMATION OF BEPOTASTINE BESILATE AND BENZALKONIUM CHLORIDE IN OPHTHALMIC FORMULATION BY RP-HPLC METHOD Original Article KRISHNA R. GUPTA a *, SONALI S. ASKARKAR a a Department of Pharmaceutical Chemistry, Smt Kishoritai Bhoyar College of Pharmacy, New Kamptee, Nagpur, Maharashtra, India Email: krg1903@gmail.com Received: 27 Feb 2016 Revised and Accepted: 20 Apr 2016 ABSTRACT Objective: Development and validation of stability indicating RP-HPLC method for the simultaneous determination of bepotastine besilate (Bepo B) and benzalkonium chloride (BKC) in an ophthalmic dosage form. Methods: A chromatographic separation of the drug, as well as a preservative, was achieved using Shimadzu HPLC 1100 series consisted of binary pump LC-10 ADvp, Rheodyne universal injector 7725i and Shimadzu SPD-10 UV–Visible detector. The chromatographic separations were performed using Analytical® Hyperchrome ODS C18, 5 μm, 250 mm X 4.6 mm i.d. column with isocratic mobile phase Acetonitrile: phosphate buffer (60:40) pH 5.5. The drug and a preservative were monitored at an ambient temperature and detection wavelength of 210 nm with a flow rate of 1 ml/min and an injection volume of 20 µl. Results: The mean % recovery at the 80, 100 and 120% level for Bepotastine and benzalkonium chloride was found to be 100.09 and 100.81% respectively and % RSD was found to be 0.21 and 0.85% respectively, which meets the established acceptance criteria. Forced degradation of bepotastine besilate was carried under alkaline, acidic, neutral, oxidative, humidity, thermal and photodegradation conditions and it was analyzed by proposed method. The drug degrades to some extent in all forced degradation condition. Conclusion: The developed method was validated as per ICH guidelines using validation parameters such as accuracy, precision, linearity and range, robustness, ruggedness, LOD, LOQ, specificity, and system suitability testing. The proposed method can be used for routine analysis stability testing and assay of bepotastine besilate ophthalmic solution in quality control laboratories. Keywords: Bepotastine besilate (Bepo B), Benzalkonium chloride (BKC) © 2016 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/ ) INTRODUCTION Bepotastine besilate (Bepo B) is a selective histamine H1-receptor antagonist. Bepreve™ (bepotastine besilate ophthalmic solution), 1.5% is a sterile ophthalmic solution of bepotastine besilate proposed for the treatment of itching associated with signs and symptoms of allergic conjunctivitis in patients aged 3 y or older. The proposed dosage and route of administration for Bepreve™ (bepotastine besilate ophthalmic solution), 1.5% is as follows: instill one drop into the affected eye(s) twice a day (BID). Bepotastine besilate (also known as TAU-284 and SNJ1773) was originally developed in Japan by Ube Industries, Ltd. and Tanabe Seiyaku Co., Ltd. as a treatment for allergic rhinitis. An oral preparation of bepotastine besilate (Talion® tablets, Mitsubishi Tanabe Pharma Corporation [formerly Tanabe Seiyaku Company, Ltd.]) was approved in Japan in July 2000 and launched in October 2000. In January 2002, the additional indication of pruritus/itching accompanying urticaria and other skin diseases was approved in Japan [1-2]. A clinical trial study showed that bepotastine, cetirizine, fexofenadine, and olopatadine inhibit the histamine-induced wheal- and-flare response of humans in vivo and induce a variable systemic sedative effect and impaired psychomotor activity [3]. Bepotastine was generally well tolerated in adult and paediatric patients with Allergic conditions. It was also noticed that bepotastine (20 mg/day) was significantly more effective than terfenadine (120 mg/day) in patients with perennial allergic rhinitis. Although a number of studies have been made to evaluate clinical efficacy and safety of bepotastine, scarcely any literature is available for its estimation [4]. Bepotastine besilate (Bepo B) chemically known as ({d-(S)-4-[4-[(4- chlorophenyl) (2-pyridyl) methoxy] piperidino} butyric acid monobenzene sulphonate), is a new second-generation antihistamine developed in Japan. It reduces the natural chemical histamine in the body which can produce allergic symptoms of itching or watery eyes. The chemical structure of bepotastine besilate is depicted in fig. 1. Fig. 1: Structure of bepotastine besilate Benzalkonium chloride (BKC), a typical quaternary ammonium salt, is often used as an antiseptic. Its structure is shown in fig. 2, and the C12 homolog is the major species in a benzalkonium chloride preparation [5]. The mode of antiseptic action of quaternary ammonium compounds appears to be associated with their effect on the cytoplasmic membrane that controls cell permeability, and the C12 homolog is most effective against yeast and fungi [6]. Fig. 2: Structure of benzalkonium chloride A literature survey reveals that Mamta D et al.,[7] developed LC- MS/MS method for estimation of bepotastine besilate. Sharath P et al.,[8] developed RP-HPLC method for estimation of Bepotastine Besilate only. Narasimha K et al.,[9] has given stability indicating HPLC method for the quantification of bepotastine besilate and its related substances. It is necessary to estimate % purity of drug as International Journal of Pharmacy and Pharmaceutical Sciences ISSN- 0975-1491 Vol 8, Issue 6, 2016