2-Phosphonomethylpentanedioic acid (1, 2-PMPA) is a potent inhibitor of glutamate carboxypeptidase II which has demonstrated robust neuroprotective efficacy in many neurological disease models. However, 1 is highly polar containing a phosphonate and two carboxylates, severely limiting its oral bioavailability. We strategized to mask the polar groups via a prodrug approach, increasing the likelihood of passive oral absorption. Our initial strategy was to cover the phosphonate with hydrophobic moieties such as pivaloyloxymethyl (POM) and isopropyloxycarbonyloxymethyl (POC) while keeping the α- and γ-carboxylates unsubstituted. This attempt was unsuccessful due to the chemical instability of the bis-POC/POM derivatives. Addition of α,γ-diesters and α-monoesters enhanced chemical stability and provided excellent oral exposure in mice, but these mixed esters were too stable in vivo, resulting in minimal release of 1. By introducing POC groups on both the phosphonate and α-carboxylate, we synthesized Tris-POC-2-PMPA (21b), which afforded excellent release of 1 following oral administration in both mice and dog.

Department of Chemistry McDaniel College Westminster Maryland 21157 United States

Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic v v i 166 10 Prague Czech Republic

Johns Hopkins Drug Discovery Johns Hopkins University Baltimore Maryland 21205 United States

Johns Hopkins Drug Discovery Johns Hopkins University Baltimore Maryland 21205 United States Johns Hopkins Department of Neurology Johns Hopkins University Baltimore Maryland 21205 United States