Determination of diclofenac residue in swine tissue following intramuscular administration

Diclofenac residue (DF) in swine tissue (liver, kidney, muscle, injection site) were examined using the method of High Performance Liquid Chromatography (HPLC) 15h, 72h,and 120h after i.m. administration of an individual therapeutic dose of diclofenac-sodium. At 15h after administration, the highest concentration of DF was found in the kidney (0.614 mg/kg), while a concentration about two times lower was found in the liver (0.316 mg/kg). At the injection site, the DF concentration was 0.432 mg/kg, while DF remained in a very low concentration (0.052 mg/kg) in the muscle outside the injection site, which was the lowest concentration in comparison with all the other examined tissues. At 72h after administration, DF was present in all examined tissues, but its concentrations were lower than the level that could be determined using the analytic procedure. Traces of the administered medicine disappeared after the waiting period of 120h in all tissues, except for the injection site. The longer presence of the medicine at the injection site could be a consequence of local inflammation, or irritation, that could cause a reduction in pH values of the area around the injection site, thus leading to slower dissolving and a longer presence of the DF at the injection site