The Pharmacokinetic Properties of Veterinary Antiparasitic Drugs in the Context of Human Pregnancy—An In Silico Study

In this study, 86 veterinary antiparasitic drugs were investigated for their ability to cross the human placenta, expressed as the Clearance Index (CI) relative to antipyrine. It was established that the CI is positively correlated with the permeability of compounds through Caco-2 cells (caco2) and with ATSC7i—the centered Broto-Moreau autocorrelation—lag 7/weighted by the first ionization potential, and inversely correlated with Topological Polar Surface Area (TPSAMord). All the studied drugs might cross the placenta, some rapidly, as suggested by their CI values. For some of the antiparasitic drugs (especially those from the pyrethroid family) investigated in this study, the placental permeability predicted using the CI values differed from predictions based on the equilibrium fetus-to-mother concentration ratio (FM), indicating the possibility of rapid clearance or metabolism. According to our QSAR analysis, almost all of the studied drugs have AChE inhibition constants (Ki) comparable to those of AChE inhibitors registered in the CHEMBL database. Molecular docking studies revealed that the drugs might engage in several types of bonds/interactions, mainly with tryptophan (Trp86, Trp286), tyrosine (Tyr124, Tyr227, Tyr341), and phenylalanine (Phe295, Phe297, and Phe338)—and with at least one amino acid from the AChE catalytic triad.