A simple method for the preparation of PEG-6-mercaptopurine for oral administration

A new and efficient method for the synthesis of PEG-6-mercaptopurine is described. The key feature of the proposed approach is the protection of the thiol group against metabolic inactivation. Preliminary in vivo and in vitro evaluations of the macromolecular prodrug have been carried out. (c) 2007 Elsevier Ltd. All rights reserved.