Should licking behavior be considered in the bioavailability evaluation of transdermal products?
Article first published online: 13 MAR 2012
Published 2012. This article is a U.S. Government work and is in the public domain in the USA
Journal of Veterinary Pharmacology and Therapeutics
Special Issue: Bioequivalence
Volume 35, Issue Supplement s1, pages 39–43, April 2012
How to Cite
TOUTAIN, P.-L., MODRIC, S., BOUSQUET-MÉLOU, A., SALLOVITZ, J. M. and LANUSSE, C. (2012), Should licking behavior be considered in the bioavailability evaluation of transdermal products?. Journal of Veterinary Pharmacology and Therapeutics, 35: 39–43. doi: 10.1111/j.1365-2885.2012.01380.x
- Issue published online: 13 MAR 2012
- Article first published online: 13 MAR 2012
- (Paper received 23 December 2011; accepted for publication 30 December 2011)
Toutain, P.-L., Modric, S., Bousquet-Mélou, A., Sallovitz, J. M., Lanusse, C. Should licking behavior be considered in the bioavailability evaluation of transdermal products? J. vet. Pharmacol. Therap.35 (Suppl. 1), 39–43.
Antiparasitic drugs, and especially macrocyclic lactones (MLs), are often formulated as pour-on products because of their ease of administration, convenience, and reduction of stress in treated animals. However, because of self- and allo-grooming, much of a drug administered transdermally may be systemically absorbed via the oral route, creating highly variable pharmacokinetic and pharmacodynamic response in treated (and untreated) animals. Testing bioequivalence (BE) of pour-on drugs in cattle under laboratory conditions (with restricted licking) ignores a major factor of drug disposition of these drugs and thus fails to predict therapeutic equivalence in the target population under clinical conditions of use. Therefore, the interanimal and intra-animal variability associated with licking behavior should be considered as a biological fact, rather than a noise that needs to be reduced or eliminated. As a result, it is recommended that the BE testing for pour-on products in cattle be conducted by evaluating both the mean and distribution of bioavailability parameters between the reference and test products when animals are not prevented from allo- and self-licking.