RESUMEN
This study was aimed to synthesize the polyethyleneglycol-polycaprolactone-polyethyleneimine (PEG-PCL-PEI) three block polymer material, prepareRhein (RH)-loaded PEG-PCL-PEI nanoparticles(PPP-RH-NPS), and then evaluate their physical and chemical properties and biological characteristics in vitro. PEG-PCL-PEI polymer was obtained by adopting thering-opening polymerization and Michael addition reaction, and their physical and chemical properties were analyzed by using NMR and gel permeation chromatography. PEG-PCL-PEI was then used as the carriers to prepare PPP-RH-NPS by applying spontaneous emulsification solvent diffusion method. The results showed that molecular weight of PEG-PCL-PEI polymer was 9.5×103, and critical micelle concentration was 0.723 mmol•L⁻¹. PPP-RH-NPS had pale yellow, opalescence faade, round and smooth without aggregation, formed of (118.3±3.6) nm in particle size with PDI of (0.19±0.08), Zeta potential of (6.3±1.5) mV, entrapment efficiency of (93.64±5.28)%, and drug loading of (8.57±0.53)%. The accumulative release percentage of PPP-RH-NPS was 75.92% in 48h, and the release profiles in PBS conformed to the Higuchi equation： Q=0.121 6t1/2+0.069 5 (R²=0.887 4), presenting slow release characteristics. Within the scope of the 0-0.05 mmol•L⁻¹, the nanoparticles had no obvious hemolysis on rabbit red blood cells and toxicity on HK-2 cells. In the investigation of uptake efficiency by flow cytometry, nanoparticles can be absorbed into cells quickly and internalized within 30 minutes fully, with a high uptake efficiency. In confocal laser scanning microscope observation, the nanoparticles can escape from lysosome into cytoplasm. Herein, this study synthesized the PEG-PCL-PEI polymer and prepared PPP-RH-NPS successfully; the nanoparticles showed uniform particle size, higher encapsulation efficiency and drug-loading rate, slow release characteristics, quick uptake and internalization, lysosome escape property and good biocompatibility. PPP-RH-NPS will be a promising pharmaceutical formulation for further development.
RESUMEN
Chemical modification is critical for the therapeutic applications of antisense oligonucleotides. Novel 4'-C-MOE and 2'-fluoro-modified monomer 2'-F-4'-C-MOE-araU and its epimeric 2'-F-4'-C-MOE-rU were synthesized from 2'-fluorinated arabinourine (2'-F-araU) and 2'-fluorouridine (2'-F-rU), respectively. Their phosphoramidites were synthesized and successfully incorporated into oligodeoxynucleotides. The mismatch discrimination ability of these unnatural monomers and their effect on thermal stability were evaluated in the context of dsDNA and DNA-RNA chimeras. The thermal denaturation studies showed that the incorporation of 2'-F-4'-C-MOE-araU led to enhanced binding affinity to complementary RNA strand and almost equivalent binding ability to complementary DNA, when compared with 2'-F-4'-C-MOE-rU and 2'-F-araU modified duplexes.Especially a C-H…F-C pseudohydrogen bond was supposed to contribute more binding affinity at uridine-purine steps, meanwhile, 2'-F-4'-C-MOE-araU had almost the same base discriminatory ability as uridine in dsDNA and DNA-RNA chimeras, while 2'-F-4'-C-MOE-rU was found to have only moderate RNA hybridization ability. However, 2'-F-4'-C-MOE-araU at 3'-end of oligonucleotide could not led to more nuclease hydrolytic stability than that with 2'-F-4'-C-MOE-rU modification. These results demonstrated the feasibility of C4'-MOE modification on 2'-F-ANA and the dramatic effects of the 2'-F substituent, which provides a new approach fo r further chemical modification of antisense drugs.