The Evaluation Of Drug-like Properties And Structure Optimization Of Diarylamide As Urea Transporter Inhibitors

Urea transporters(UTs)have been identified as new targets for diuretics.Urea concentration gradient mediated by UTs plays a vital role in urine concentration.Functional deletion of UTs led to urea-selective urinary concentrating defects with relative salt sparing,which reminds that UTs are novel targets as diuretics especially for water retention diseases that need long use of diuretics.In our previous study,a UT inhibitor with a diarylamide scaffold,which is denoted as 1H,was demonstrated as the first orally available UT inhibitor.However,the oral bioavailability of 1H was only 4.38%,which obstructed its clinical application.In this work,we did preclinical pharmacological research of 3F.We applied CCK-8 kit to evaluate the cytotoxicity of compounds,transwell experiments to assess the inhibition selectivity of UT-A1 and UT-B,rats/mice models to confirm the diuretic effects in vivo by intragastric administration or subcutaneous injection.Compared with 1H,3F showed a 10 times stronger inhibitory effect on UT-B(0.14 μmol/L vs.1.41 μmol/L in rats,and 0.48 μmol/L vs.5.82 μmol/L in mice)and a much higher inhibition rate on UT-A1.Moreover,the metabolic stability both in vitro and in vivo and the drug-like properties(permeability and solubility)of3F were obviously improved obviously compared with those of 3F.Moreover,the bioavailability of 3F was 15.18%,which was 3 times higher than that of 3F,thereby resulting in significant enhancement of the diuretic activities in rats and mice.In addition,in a singledose toxicity experiment,all animals survived at 2000 mg/kg,and no clinical signs were observed.We also optimized the synthetic route of 3F.At the same time,as continuation of previous study,we modified 5 series total 47 compounds,and assessed their bioactivities.From them,22 compounds showed better bioactivities than 1H,and all E series compounds possessed UT-B inhibition which deserve further investigation.SAR studies were summarized as follows.A)acetyl amide in benzene part was not necessary,which could be replaced with quinolinone or benzene sulfonamide;B)any changes of 5-position in furan ring would decrease or disappear bioactivity;C)amide linker could be modified,proper substituted acylhydrazone might be beneficial.In this study,we discovered benzene sulfonamide series(E series)as potent active compounds and provide preclinical studies of candidate compound 3F.