title: In vitro evaluation of 9-(2-phosphonylmethoxyethyl)adenine ester analogues, a series of anti-HBV structures with improved plasma stability and liver release.
abstract: Chronic hepatitis B virus (HBV) infection may lead to liver cirrhosis and hepatocellular carcinoma, but few drugs are available for its treatment. Acyclic nucleoside phosphonates (ANPs) have remarkable antivirus activities but are not easily absorbed from the gastrointestinal tract and accumulate in the kidneys, resulting in nephrotoxicity. Therefore, there is a need to find effective liver site-specific prodrugs. The dipivaloyloxymethyl ester of 9-(2-phosphonylmethoxyethyl)adenine (PMEA)-adefovir dipivoxil (ADV)-is a first-line therapy drug for chronic hepatitis B with a low therapeutic index because of renal toxicity and low hepatic uptake. In this study, a series of PMEA derivatives were synthesized to enhance plasma stability and liver release. The metabolic stability of ADV (Chemical I) and its two analogues (Chemicals II and III) was evaluated in rat plasma and liver homogenate in vitro. An ion-pair reverse-phase HPLC-UV method and a hybrid ion trap and high-resolution time-of-flight mass spectrometry (LC-IT-TOF-MS) were used to evaluate the degradation rate of the analogues and to identify their intermediate metabolites, respectively. Chemicals I and II were hydrolyzed by cleavage of the C-O bond to give monoesters. Sufficient enzymatic activation in the liver homogenate through a relatively simple metabolic pathway, in addition to a favorable stability profile in rat plasma, made Chemical II an optimal candidate. Next, six analogues based on the structure of Chemical II were synthesized and evaluated in plasma and liver homogenate. Compared to Chemical II, these compounds generated less active PMEA levels in rat liver homogenate. Therefore, chemical modification of Chemical II may lead to new promising PMEA derivatives with enhanced plasma stability and liver activation.
authors: Beijing Institute of Pharmacology and Toxicology, 27 Taiping Road, Haidian District, Beijing, 100850, People's Republic of China.
authors: Sha
authors: S
authors: Liao
authors: Shi-Yong
authors: SY
authors: Fan
authors: Qin
authors: Q
authors: Liu
authors: Chang-Kun
authors: CK
authors: Li
authors: Jia
authors: J
authors: Chen
authors: Jing-Lai
authors: JL
authors: Li
authors: Zhi-Wei
authors: ZW
authors: Zhang
authors: Zhen-Qing
authors: ZQ
authors: Zhang
authors: Bo-Hua
authors: BH
authors: Zhong
authors: Jian-Wei
authors: JW
authors: Xie
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000097:blood / Q000138:chemical synthesis / Q000494:pharmacology; D000818:Animals; D000998:Antiviral Agents / Q000097:blood* / Q000138:chemical synthesis* / Q000494:pharmacology; D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid; D004353:Drug Evaluation, Preclinical; D065546:Drug Liberation; D004355:Drug Stability; D004952:Esters; D006515:Hepatitis B virus / Q000187:drug effects*; D066298:In Vitro Techniques; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D015394:Molecular Structure; D063065:Organophosphonates / Q000097:blood* / Q000138:chemical synthesis* / Q000494:pharmacology; D051381:Rats; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000998:Antiviral Agents; D004952:Esters; D063065:Organophosphonates; D000225:Adenine; C106812:adefovir dipivoxil