Avermectins, new family of potent anthelminthic agents, efficacy of the B1a component.

Campbell and colleagues reported unprecedented antiparasitic effects of the agent in vivo, and that the "B1a" component of the molecule was most effective as a single oral dose.
(Order of authorship in the original publication: Egerton, Oslin, Blair....Campbell.) Digital facsimile from PubMedCentral at this link.

In 2015 William C. Campbell shared half of the Nobel Prize in Physiology or Medicine with Satoshi Ōmura “for their discoveries concerning a novel therapy against infections caused by roundworm parasites.” The other half was awarded to Tu Youyou “for her discoveries concerning a novel therapy against Malaria.”

(Thanks to Juan Weiss for this reference and its interpretation.)