Evaluation of the bioequivalence of two erythromycin thiocyanate formulations after oral administration to broiler chickens

Twenty-one eight-week-old healthy broiler chickens of both sexes were used in the experiment. The birds were randomly allotted to three groups: two experimental (A and B) and one control. The chickens from group A received erythromycin in the form of granulate (Erytrowet® granulat), while the chickens from group B received erythromycin as a powder (Erytrowet®). Both formulations were administrated orally at a single dose of 25 mg/kg b.w. Blood samples were collected at 0.5, 1, 2, 2.5, 3, 4, 6, 8 and 12 h after administration of the drugs. Erythromycin concentrations were determined by the HPLC method. Comparison of the plasma pharmacokinetic profiles of both products indicated that there were no differences in the basic pharmacokinetic parameters between both formulations. The results indicate that the formulations used in this study are bioequivalent.