Skip to Content
Merck
  • In vitro evaluation of 9-(2-phosphonylmethoxyethyl)adenine ester analogues, a series of anti-HBV structures with improved plasma stability and liver release.

In vitro evaluation of 9-(2-phosphonylmethoxyethyl)adenine ester analogues, a series of anti-HBV structures with improved plasma stability and liver release.

Archives of pharmacal research (2013-12-18)
Sha Liao, Shi-Yong Fan, Qin Liu, Chang-Kun Li, Jia Chen, Jing-Lai Li, Zhi-Wei Zhang, Zhen-Qing Zhang, Bo-Hua Zhong, Jian-Wei Xie
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.

MATERIALS
Product Number
Brand
Product Description

Supelco
Acetic acid, analytical standard
Sigma-Aldrich
Trichloroacetic acid, ACS reagent, for the determination of Fe in blood according to Heilmeyer, ≥99.5%
Supelco
Ammonium acetate, LiChropur, eluent additive for LC-MS
Sigma-Aldrich
Acetic acid, for luminescence, BioUltra, ≥99.5% (GC)
Sigma-Aldrich
Acetic acid, ≥99.5%, FCC, FG
Sigma-Aldrich
Trichloroacetic acid, ACS reagent, ≥99.0%
Sigma-Aldrich
Ammonium acetate, reagent grade, ≥98%
Sigma-Aldrich
Trichloroacetic acid, suitable for electrophoresis, suitable for fixing solution (for IEF and PAGE gels), ≥99%
Sigma-Aldrich
Trichloroacetic acid, BioXtra, ≥99.0%
Sigma-Aldrich
Ammonium acetate, BioXtra, ≥98%
Sigma-Aldrich
Ammonium acetate solution, for molecular biology, 7.5 M
Sigma-Aldrich
Lamivudine, ≥98% (HPLC), powder
Sigma-Aldrich
Adefovir, ≥98% (HPLC)
Sigma-Aldrich
Acetic acid-12C2, 99.9 atom % 12C
Sigma-Aldrich
Trichloroacetic acid, ≥99.0% (titration)
Sigma-Aldrich
Ammonium acetate solution, BioUltra, for molecular biology, ~5 M in H2O
Sigma-Aldrich
Trichloroacetic acid, BioUltra, ≥99.5% (T)
USP
Lamivudine, United States Pharmacopeia (USP) Reference Standard
Sigma-Aldrich
Acetic acid, natural, ≥99.5%, FG
Sigma-Aldrich
Acetic acid solution, suitable for HPLC
Sigma-Aldrich
Acetic acid, glacial, ACS reagent, ≥99.7%
Sigma-Aldrich
Acetic acid, glacial, puriss., 99-100%
Sigma-Aldrich
Acetic acid, glacial, puriss., meets analytical specification of Ph. Eur., BP, USP, FCC, 99.8-100.5%
Sigma-Aldrich
Acetic acid, glacial, ReagentPlus®, ≥99%
Supelco
Lamivudine, Pharmaceutical Secondary Standard; Certified Reference Material
Lamivudine, European Pharmacopoeia (EP) Reference Standard
Lamivudine for system suitability 1, European Pharmacopoeia (EP) Reference Standard
Sigma-Aldrich
Acetic acid, glacial, ≥99.99% trace metals basis
Sigma-Aldrich
Ammonium acetate, ACS reagent, ≥97%
Sigma-Aldrich
Acetic acid, glacial, puriss. p.a., ACS reagent, reag. ISO, reag. Ph. Eur., ≥99.8%