UV spectrophotometric flow-injection assay of tetracycline antibiotics retained on Sephadex QAE A-25 in drug formulations

摘要

F flow injection analysis syste with solid phase spectrophotometric transduction has been developed for the assay of tetracycline(TC),doxycicline (DTC),oxycicline (OTC) and chlotetrqcycline (CTC).The packing material of the flow-through cell consists of Sephadex QAE A-25 resin on which tetracyclines are temporarily retained.The carrier itself acts as the desorbing solution.The measurements of the intrinsic absorbance of tetracyclines (1000 #mu#l of sample volume) were made at 380 nm (TC,DTC and OTC) and 387 nm (CTC).The detection limits were found to be 0.069(TC and OTC0,0.081 (DTC and 0.121 (CTC)#mu#g ml~(-1) and the linear dynamic range extended between 0.5 and 12(TC,DTC and OTC) and 1-20 3mu#g ml~(-1) (CTC).The relative standard deviations (n-10) ranged between 0.7 and 1.2%.A study of the potentially interfering species was carried out.Using the proposed method,tetracyclines were satisfactorily determined without any interference from excipients in pharmaceutical preparations.