Clickable, acid labile immunosuppressive prodrugs for in vivo targeting.

Allotransplantation offers the potential to restore the anatomy and function of injured tissues and organs, but typically requires life-long, systemic administration of immunosuppressive drugs to prevent rejection, which can result in serious complications. Targeting the immunosuppressive drug to the graft favors local tissue concentration versus systemic drug exposure and end-organ toxicity. This could reduce the overall dose and dosing frequency of immunosuppressive drugs, and improve the safety and efficacy of treatment. Here, we developed dibenzocyclooctyne (DBCO)-modified prodrugs of the immunosuppressive drugs tacrolimus, rapamycin and mycophenolic acid, and demonstrated their targeted conjugation both in vitro and in vivo to azido-modified hydrogels via Click chemistry. Such azido-modified hydrogels placed in transplanted tissues enable sustained local release of drugs, and could be repeatedly refilled with systemically administered acid-labile prodrugs after drug exhaustion. Thus, clickable prodrugs with degradable linkers provide new possibilities for graft targeted immunosuppression in the context of allotransplantation.

Replenishable drug depot to combat post-resection cancer recurrence.

Local drug presentation made possible by drug-eluting depots has demonstrated benefits in a vast array of diseases, including in cancer, microbial infection and in wound healing. However, locally-eluting depots are single-use systems that cannot be refilled or reused after implantation at inaccessible sites, limiting their clinical utility. New strategies to noninvasively refill drug-eluting depots could dramatically enhance their clinical use. In this report we present a refillable hydrogel depot system based on bioorthogonal click chemistry. The click-modified hydrogel depots capture prodrug refills from the blood and subsequently release active drugs locally in a sustained manner. Capture of the systemically-administered refills serves as an efficient and non-toxic method to repeatedly refill depots. Refillable depots in combination with prodrug refills achieve sustained release at precancerous tumor sites to improve cancer therapy while eliminating systemic side effects. The ability to target tissues without enhanced permeability could allow the use of refillable depots in cancer and many other medical applications.

Development of a Potent and Selective HDAC8 Inhibitor.

A novel, isoform-selective inhibitor of histone deacetylase 8 (HDAC8) has been discovered by the repurposing of a diverse compound collection. Medicinal chemistry optimization led to the identification of a highly potent (0.8 nM) and selective inhibitor of HDAC8.

Multidimensional Screening and Methodology Development for Condensations Involving Complex 1,2-Diketones.

Multidimensional reaction screening employing complex 1,2-cycloheptanediones is described. The studies have enabled the discovery of regioselective, Lewis acid-mediated condensations with substituted ureas and a diastereoselective hydrogenation process which proceeds via an interesting allylpalladium hydride isomerization.