Bioequivalence of four preparations of enrofloxacin in poultry

In various parts of the world, many 10% enrofloxacin commercial preparation s for water medication of chicken are being employed. To avoid the developm ent of bacterial resistance to this agent, the original trademark and simil ar preparations must be bioequivalent. To assess whether or not bioequivale nce exists among the pioneer vs. three commercial preparations of enrofloxa cin, a controlled pharmacokinetic study was conducted. The following variab les were compared: maximal plasma concentration (C-peak), time to C-peak, b ioavailability (expressed as the area under the concentration vs. time curv e), elimination half-life, and the shapes of the respective time-serum conc entrations of enrofloxacin profiles. Results indicate that all three simila r commercial preparations had lower C-peak values than the reference formul ation, being 39.62 to 67.77% of the corresponding C-peak reference. Additio nally, bioavailability of enrofloxacin in the pioneer product was statistic ally higher (P < 0.05). Based upon these results, we conclude that although all preparations were formulated as water-soluble products, bioequivalence studies are mandatory for the analogue formulations to ensure product comp arability. Lack of product bioequivalence could facilitate the development of bacterial resistance and limit the useful life span of the product.