936-70-9Relevant articles and documents
Thermo/pH Dual Responsive Mixed-Shell Polymeric Micelles Based on the Complementary Multiple Hydrogen Bonds for Drug Delivery
Wu, Qiuhua,Tang, Xiuping,Liu, Xue,Hou, Yu,Li, He,Yang, Chen,Yi, Jie,Song, Ximing,Zhang, Guolin
, p. 112 - 119 (2016)
Thermo/pH dual responsive mixed-shell polymeric micelles based on multiple hydrogen bonding were prepared by self-assembly of diaminotriazine-terminated poly(ε-caprolactone) (DAT-PCL), uracil-terminated methoxy poly(ethylene glycol) (MPEG-U), and uracil-terminated poly(N-vinylcaprolactam) (PNVCL-U) at room temperature. PCL acted as the core and MPEG/PNVCL as the mixed shell. Increasing the temperature, PNVCL collapsed and enclosed the PCL core, while MPEG penetrated through the PNVCL shell, thereby leading to the formation of MPEG channels on the micelles surface. The low cytotoxicity of the mixed micelles was confirmed by an MTT assay against BGC-823 cells. Studies on the in vitro drug release showed that a much faster release rate was observed at pH 5.0 compared to physiological pH, owing to the dissociation of hydrogen bonds. Therefore, the mixed-shell polymeric micelles would be very promising candidates in drug delivery systems.
Base-modified doxorubicin prodrug and preparation method and application thereof
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Paragraph 0056; 0058, (2021/10/02)
Base-modified doxorubicin prodrug and preparation method and application thereof The invention belongs to the field of new auxiliary materials and new dosage forms of pharmaceutical preparations, and particularly provides a base-modified doxorubicin prodrug, and the prodrug and the nucleoside analogue are assembled into nanoparticles. Efficient CO-loading and co-delivery of the base-modified doxorubicin prodrug with nucleoside analogs is achieved by hydrogen bonding force binding. To the method, the cardiotoxicity of doxorubicin is reduced, the redox heterogeneity of the tumor cell microenvironment can be effectively solved, and the prepared nanoparticles are small and uniform in particle size. Compared with the surface modification, the circulating time of nanoparticles in blood can be prolonged through PEG modification, so that the drug loading is ultrahigh, and adverse reactions and toxicity related to auxiliary materials are favorably reduced. The method is simple in preparation process and easy to amplify and produce.
Syntheses and energy transfer in multiporphyrinic arrays self-assembled with hydrogen-bonding recognition groups and comparison with covalent steroidal models
Balaban, Teodor Silviu,Berova, Nina,Drain, Charles Michael,Hauschild, Robert,Huang, Xuefei,Kalt, Heinz,Lebedkin, Sergei,Lehn, Jean-Marie,Nifaitis, Fotis,Pescitelli, Gennaro,Prokhorenko, Valentyn I.,Riedel, Gernot,Smeureanu, Gabriela,Zeller, Joachim
, p. 8411 - 8427 (2008/09/16)
A number of new porphyrins equipped with complementary triple hydrogen-bonding groups were synthesized in good yields. Self-assembly was investigated by NMR spectroscopy, dynamic light scattering (DLS), and atomic force microscopy (AFM). These artificial antenna systems were further characterized by stationary and time-resolved fluorescence techniques to investigate several yet unsolved questions on the mechanism of excitation energy transfer (EET) in supramolecular systems. For example, the photo-physics of a simple D - U≡P - A dyad was studied, in which donor D and acceptor A are ZnII- metalated and free-base porphyrins, respectively, and U (uracyl) and P (2,6-diacetamidopyridyl) are complementary hydrogen-bonding groups linked by flexible spacers. In this dyad, the EET occurs with about 20% efficiency with a lifetime of 14 ps. Reversal of the nonsymmetric triple hydrogen-bonding groups to give a A - U≡P - D construct results in an EET efficiency of about 25% and a lifetime of 19 ps. Thus, there is a slight directionality of EET mediated by these asymmetric triple hydrogen-bonding units tethered to flexible spacers. In polymeric systems of the type ...P-D-P≡U-A-U≡P-D-P..., or ...D-U≡P-A- P≡U-D-U..., the EET efficiency doubles as each donor is flanked by two acceptors. Because doubling the probability of photon capture doubles the EET efficiency, there is no energy amplification, which is consistent with the "antenna effect". For these polymeric systems, AFM images and DLS data indicate large rodlike assemblies of a few hundred nanometers, whereas the components form much smaller aggregates under the same conditions. To understand the importance of the flexible hydrogen-bonding zipper, three different covalently bridged D-B-A molecules were synthesized in which the bridge B is a rigid steroidal system and the same ester chemistry was used to link the porphyrins to each end of the steroid. The geometry inferred from molecular modeling of D-B-A indicates geometric similarities between B and some conformations of the -P≡U- supramolecular bridge. Although the EET efficiency is a factor of two greater for the steroidal systems relative to the supramolecular dyads, the rate is 50-80 times slower, but still slightly faster than that predicted by Foerster-type mechanisms. Circular dichrosim (CD) spectra provide a conformational sampling of the porphyrin groups appended on the steroidal skeleton, thus allowing an estimation of the orientation factor κ for the transition dipole moments, which significantly affects the EET rate. We conclude that the flexible hydrogen-bonded linked systems are adaptive and have variable geometries with foldamers in which the D and A groups can approach well under 1 nm. In these folded conformations, a rapid EET process occurs, probably also involving a Dexter-type exchange mechanism, thus explaining the fast EET relative to the rigid steroidal compounds. This study predicts that it is indeed possible to build large supramolecular antennas and the component design and supramolecular dynamics are essential features that dictate EET rates and efficiencies.
