Sulfonamide Prodrugs with a Two-Stage Release Mechanism for the Efficient Delivery of the TLR4 Antagonist TAK-242

We previously demonstrated that the potent TLR4 inhibitor TAK-242 could be covalently conjugated to pancreatic islets using a linker that afforded an effective sustained delivery of the active drug after transplant. This drug-eluting tissue achieved local inhibition of TLR4-linked inflammation and proved beneficial to the islet graft survival. Here, we describe a new family of prodrugs with a modular design featuring a self-immolative para-aminobenzyl spacer bonded directly to the TAK-242 sulfonamide nitrogen, a tether for bioconjugation, and a β-eliminative arylsulfone "trigger". The inclusion of the para-aminobenzyl spacer affords a more stable prodrug which exhibits complex drug-release kinetics due to a two-stage release mechanism. This manuscript reports the preparation and characterization of several TAK-242 prodrugs fitted with different triggers and linkers and demonstrates that these second-generation prodrugs effectively release TAK-242 while avoiding nonproductive sulfonamide hydrolysis.

The antigenic epitopes of human grown hormone as mapped by monoclonal antibodies

The antigenic epitopes of human GH (hGH) have been investigated using monoclonal antibodies (Mabs) to hGH. A panel of 12 Mabs was incorporated into two-site binding assays in order to investigate the antigenic surface of hGH. Nine reaction patterns were observed. The Mabs were further characterized in terms of their cross-reactivity with human placental lactogen, human PRL, with recombinant hGH molecules (MetLeu8hGH, Met14hGH), and with fragments derived from enzymatic or chemical digestion of hGH. These studies provided information on the antigenic sites that are shared with human placental lactogen and on the N-terminal and C-terminal regions of the hGH molecule. Based upon these findings, we tentatively suggest the epitope model for hGH comprising at least 10 antigenic sites (epitopes) which may be grouped into five antigenic regions.