Novel Cationic Surfactants Derived From Metal Ion Cage Complexes: Potential Antiparasitic Agents

Abstract

The paper describes the synthesis and properties of a series of macrobicyclic cage cobalt(III) complexes which have lipophilic substituents . Those with paraffin tails, C₈ or larger, have detergent-like characteristics and are able to penetrate biological membranes. A selection of the reagents was tested in vitro against parasitic nematodes, cestodes, trematodes and protozoa. Compounds with tails longer than C₈ effectively killed the organisms at concentrations ≤10^-3 M. In vivo against cestodes, that activity was also evident and biodistribution following oral administration showed that the compounds were confined to the gastrointestinal tract, unlike organic detergents such as cetylpyridinium chloride which are absorbed systemically. It is argued that the high charge and size of the head group of the complex detergents destabilize the exterior membrane of the organism. This new class of detergents, appropriately formulated, may be an effective new method of treating gastrointestinal parasites via this novel mode of action.