Synthesis and bioactivity of mixed phosphonate derivatives of adefovir with hepatic targeting property

In order to search for new adefovir analogues as anti-HBV agents with enhanced antiviral activity and hepatotrophic property, adefovir bis L-amino acid ester was used as lead compound to produce ten adefovir mono L-(thio)amino acid ester, mono bile acid ester derivatives( 6a-6j ). The design based on bile acid prodrug strategy, which can improve drug oral bioavaliability and liver-targeted enrichment by using enterohepatic circulation of bile acid. Sub-structure combination method was adopted to introduce L-(thio)amino acid ester and bile acid ester fragments on the phosphonate functionality of adefovir. The structures of target compounds were confirmed by ¹H NMR, ¹³C NMR, ESI-MS and ESI-HRMS. HepG 2. 2. 15 cell were used for in vitro anti-HBV activity assessment. Compound 6c with high antiviral activity(EC₅₀ 0. 92μmol/L, SI 512. 63)was further investigated for its tissue distribution in mice. The results showed that content of compound 6c in liver was higher than that of adefovir dipivoxil, and in contrast its content in kidney was lower than that in positive control at all time points(0. 25-12 h). Compound 6c exhibits higher antiviral activity, selective index and higher liver distribution, making it a potential anti HBV agent for further investigation.