Determination of oxytetracycline in biological matrix.

Oxytetracycline (OTC) has been used for years in medical field. It is a wide-spectrum antibiotic, belonging to the group of tetracyclines with bacteriostatic activity (1-4). OTC chemical name is 4-(dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro3,5,6,10,12,12a-hexahydroxy-6-methyl-1,11-dioxotetracene-2-carboxamide. OTC possesses broad antimicrobial spectrum, similar to tetracycline. The antibiotic displays high activity against aerobic Gram-positive and Gram-negative bacteria, Rickettsia, Mycoplasma and Chlamydia. OTC is used for the treatment of respiratory, urinary and alimentary tract infections, because of its activity, low toxicity and good penetration into tissues (1-3, 5). OTC is rapidly absorbed from the gastrointestinal tract. The absorption is reduced significantly by dairy products due to the calcium content, which takes part in the formation of chelate compounds. OTC may cause photosensibilisation (1-4). Several methods have been published describing the determination of OTC in premixes and animals tissues (7,9-12). These method are, however, time-consuming and arenít as accurate as the method described in this paper. The present report deals with a simple, sensitive, rapid and economical HPLC method for determination of OTC in plasma. The aim of the present study was to develop a time saving, cost-effective and sensitive method for determination of OTC in biological matrix.