A process for the extraction of sulphadiazine (SDZ) and trimethoprim (TMP) from broiler fortified tissues (plasma, lung, liver, kidney, fat, muscle, skin) was developed and a liquid chromatographic (LC) method for their determination is described. After extraction in acidic medium (pH 6.8) with ethyl acetate or dichloromethane, the extracts were purified with hexane-chloroform in an acidic buffer. Reversed-phase LC separation with gradient elution (phosphate buffer-acetonitrile) was applied. The values obtained for the quantification limit for both drugs are 0.100 mu g ml(-1) for plasma, 0.100 mu g g(-1) for lung and 0.050 mu g g(-1) for the other tissues. The detection limits range from 0.010 to 0.015 mu g g(-1) or ml(-1) and from 0.020 to 0.025 mu g g(-1) or ml(-1) for SDZ and TMP, respectively. Recoveries, established by comparison of peak areas obtained with standards and those with fortified tissue, ranged between 85.7 and 67.2%, depending on the tissue.
