TRANSPORT AND REACTIVATION BEHAVIOR OF NERVE AGENT ANTIDOTES

The blood-brain barrier is a system of capillaries and supporting cells that maintain homeostasis in the brain and prevent toxin entry. Organophosphates are among the few drugs that enter the brain and inhibit acetylcholinesterase, the enzyme that breaks down the neurotransmitter, acetylcholine. Organophosphates are a class of compound with a central phosphate surrounded by electronegative atoms. This organophosphate chemical class is largely made up of pesticides, but also contain nerve agents, like sarin or VX. The antidotes to organophosphates, called oximes, have a relatively intensive treatment regime and the mechanistic bottle necks in treatment were unknown. We have shown that the most common U.S. antidote, 2-PAM, as well as two novel oxime antidotes, have relativity low apparent permeability in both Madin-Darby Canine Kidney cells (MDCK) and induced pluripotent stem cell derived human brain microvascular endothelial cells (iPSC dhBMEC) using transwell assays. A comparison of dhBMEC and MDCKII permeability for a library of solutes was also done. Next, a reactivation assay was designed and used to assess the reactivation capabilities when permeability and reactivation were coupled. It was found that the novel oximes out performed 2-PAM significantly when permeability across a cell monolayer was coupled with reactivation of acetylcholinesterase inhibited by a variety of organophosphates. Once the mechanistic bottle necks of moderately slow brain permeability and relatively quick clearance from the body were understood, we explored different drug delivery systems designed to increase brain penetration and circulation time. Several stable formulations of a CD47, marker-of-self, and RVG, rabies virus glycoprotein, liposomes were synthesized. Permeability of these liposomes was completed and RVG had no positive effect on permeability through dhBMECs