Dipeptidyl Peptidase IV Dependent Water-Soluble Prodrugs of Highly Lipophilic Bicyclic Nucleoside Analogues

We present the first report of the application of the dipeptidyl peptidase IV (DPPIV/CD26) based prodrug approach to hydroxy-containing drug derivatives. In particular, we applied this strategy to the highly lipophilic antiviral drug family of bicyclic furanopyrimidine nucleoside analogues (BCNA) in order to improve their physicochemical and pharmacokinetic properties. Our stability data demonstrated that the prodrugs efficiently release the parent BCNA drug upon selective conversion by purified DPPIV/CD26 and by soluble DPPIV/CD26 present in bovine, murine, and human serum. Vildagliptin, a specific inhibitor of DPPIV/CD26, was able to completely block the hydrolysis of the prodrugs in the presence of purified DPPIV/CD26 human, murine, and bovine serum. Several novel prodrugs showed remarkable increases in water solubility (up to more than 3 orders of magnitude) compared to the poorly soluble parent drug. We also demonstrated a markedly enhanced oral bioavailability of the prodrugs versus the parent drug in mice.