Engineering prolonged-acting prodrugs employing an albumin-binding probe that undergoes slow hydrolysis at physiological conditions.

Here we describe the design and application of OSu-FMS-MAL-S-(CH(2))(15)-COOH, an agent that associates with albumin while linked to a peptide or a protein with sufficient affinity (Ka=2 to 2.6 x 10(5)M(-1)) to protract the action of short- lived peptides and proteins in vivo. Under physiological conditions this probe undergoes spontaneous hydrolysis with the concomitant reactivation of inactive conjugates. Intravenously administered (125)I-labeled-Insulin-FMS-MAL-S-(CH(2))(15)-COOH to rats shows half-life of 17+/-2h, exceeding 5.2 times that obtained with intravenously administered (125)I-labeled Insulin. In mice this derivative facilitates glucose-lowering effect over a period of 24h, yielding AUC five times greater than that obtained by a similar dose of insulin-detemir. Similarly, subcutaneous administration of Exendin-4-FMS-MAL-S-(CH(2))(15)-COOH into mice facilitated prolonged and stable reduction in glucose level, yielding a t(1/2) value of 28+/-2h, exceeding the effect of exendin-4 4.7 folds. The inactive derivative gentamicin-FMS-MAL-S-(CH(2))(15)-COOH regained its full antibacterial potency upon incubation at physiological conditions yielding a t(1/2) value of 7.1+/-0.2h. In conclusion, the albumin-binding probe we introduced enables to prolong the action of any amino containing molecule in vivo, without the drawback of inactivation that often occurs upon such derivatization. Copyright 2009 Elsevier B.V. All rights reserved.