Synthesis of poly(vinyl alcohol)-doxorubicin conjugates containing cis-aconityl acid-cleavable bond and its isomer dependent doxorubicin release.
Aconityl-doxorubicin (ADOX) was synthesized by the modified method of Shen and Ryser. Two isomers of cis-ADOX (cis-configuration) and trans-ADOX (trans-configuration) were generated in the reaction of DOX and cis-aconitic anhydride. These products were separated completely by using HPLC and analyzed by TOF-MS spectroscopy and (1)H- and (13)C-NMR experiments. The yields of cis-ADOX and trans-ADOX were 36.3 and 44.8%, respectively. The free gamma-carboxylic group of ADOX molecule was coupled to poly(vinyl alcohol) (PVA) via ethylenediamine spacer, resulting the macromolecular conjugates of PVA-cis-ADOX and PVA-trans-ADOX, respectively. The DOX content of the conjugates estimated by the hydrolysis method detected the aglycone of DOX which can be estimated as the PVA-bound DOX selectively was 4.4 w/w% which was similar to 4.6 w/w% by the ordinary UV method. Both PVA-cis-ADOX and PVA-trans-ADOX were very stable at neutral pH, but the release of DOX was increased markedly under acidic conditions. Half-life of the release of DOX from PVA-cis-ADOX at pH 5.0 was 3 h which was 4.7-fold shorter than that from PVA-trans-ADOX (14 h). The cytotoxicities of PVA-cis-ADOX and PVA-trans-ADOX were evaluated by using J774.1 cells employing a [(3)H]uridine incorporation assay as a measure of RNA synthesis. A significant difference in antitumor activity between PVA-cis-ADOX and PVA-trans-ADOX was observed where the former was much active than the later. It was suggested that the conjugate enters the cells and reaches the lysosomal/endosomal compartment, and that the aconityl spacer releases DOX from the conjugate in the acidic compartment of lysosomes/endosomes due to the participation of a free carboxylic group.
Kakinoki
Atsufumi
A
Laboratory of Biopharmaceutics, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan.
Kaneo
Yoshiharu
Y
Ikeda
Yuka
Y
Tanaka
Tetsuro
T
Fujita
Kahee
K
D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000493:pharmacokinetics / Q000494:pharmacology; D004317:Doxorubicin / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D051379:Mice; D011142:Polyvinyl Alcohol / Q000737:chemistry*
D000970:Antineoplastic Agents; C062167:aconityldoxorubicin; D004317:Doxorubicin; D011142:Polyvinyl Alcohol