The Global Journal of Pharmaceutical Research Vol. 3 (3), pp. 1978-84, Sep, 2014; www.tgjpr.com Naveed et al. 1978 Doxycycline is a semi-synthetic, lipophilic and potent tetracycline congener, widely used in human and veterinary medicine and as an animal feed supplement to prevent disease. It is the drug of choice in the treatment of Lyme disease, Brucellosis, and several Rickettsial infections, and it is also utilized in the treatment of sexually transmitted diseases. Forced degradation commonly includes exposure of drug to heat, range of pH values, UV light, forced degradation study helps to determine the loss of drug substance and the degradation product under diverse conditions.. According to ICH guidelines Doxycycline was exposed to different stress conditions. For the analysis of drug in the presence of degradation products, UV spectroscopic method was developed which calculate the amount of the degradaded product. According to the BP, the official assay limit of th content should NLT 95% and NMT 105% of labelled amount. On exposure to acidic medium (1 N HCl) shows heavy degradation, whereas comparatively less degradation occurs with heat, in addition UV light and basic medium (1 N NaOH) has least degradation effect on doxycycline. The method was found to be simple, cost effective and less time consuming. Hence this method can be successfully used. KEYWORDS: Doxycycline, Assay, Degradation studies INTRODUCTION Doxycycline is a potent tetracycline drug it is semi-synthetic and lipophilic in nature. It has superior pharmacokinetics, long half-life, better safety profile, low resistance potential and lower cost 1,2,3,4,5 . It is rapidly absorbed following oral absorption; it is suggested that peak absorption occurs in the duodenum. Unlike other tetracycline, doxycyline absorption is not influenced by simultaneous ingestion of food or milk however absorption may be reduced by antacids containing high concentration of aluminium, calcium and magnesium 6 . Doxycycline (DOX), 1-dimethylamino-2, 4a, 5, 7, 12-pentahydroxy-11- methyl - 4, 6-dioxo 1,4a,11,11a,12,12a- hexahydrotetracene-3-carboxamide (Figure 1) is a broad spectrum tetracycline antibiotic, widely used in human and veterinary medicine and as an animal feed supplement to prevent disease. It is the drug of choice in the treatment of Lyme disease, Brucellosis, and several Rickettsial infections, and it FULL LENGTH RESEARCH ARTICLE ISSN 2277-5439 DEGRADATION STUDY OF SIX DIFFERENT BRANDS OF DOXYCYCLINE USING UV SPECTROPHOTOMETER *Safila Naveed, Hina Qamar, Wardha Jawaid, Urooj Bokhari Faculty of Pharmacy, Jinnah University for Women, Karachi, Pakistan *Corresponding E-mail: safila117@yahoo.com Accepted 1 st Sep, 2014