Dual-functionalized PAMAM dendrimers with improved P-glycoprotein inhibition and tight junction modulating effect.
This study aims to surface modify poly(amido amine) or PAMAM dendrimers by sequentially grafting poly(ethylene glycol) or PEG and 4-thiobutylamidine (TBA) so as to reduce PAMAM cytotoxicity while improving the ability of PAMAM to modulate P-glycoprotein (P-gp) efflux and tight junction integrity. Conjugation of functional groups was determined by NMR spectroscopy, FT-IR, thiol group quantification and molecular weight estimation. The yield of the dual-functionalized dendrimers was >80%. The dual-functionalized dendrimer could significantly reduce PAMAM cytotoxicity to <15% as reflected by LDH release in Caco-2 and MDCK/MDR1 cells after 72 h of exposure. Thiolated dendrimers could increase cellular accumulation and permeation of the P-gp substrate R-123, and such effect could be affected by the extent of PEGylation of the dendrimer. Surface-modified PAMAM dendrimers, either by single or dual functionalization, could better modulate tight junction integrity in comparison with unmodified PAMAM, as demonstrated through immunostaining of the tight junction marker ZO-1, permeation of the model compound Lucifer Yellow (LY) and transepithelial electrical resistance (TEER). Of importance, reversible tight junction modulating effect was only observed in the dual-functionalized dendrimers. Collectively, dual functionalization with PEG and TBA represented a promising approach in altering PAMAM dendrimer surface for potential application in oral drug delivery.
Department of Pharmacy, Faculty of Science, National University of Singapore , Block S4, 18 Science Drive 4, Singapore 117543.
Yuanjie
Y
Liu
Gigi N C
GN
Chiu
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000578:Amidines / Q000737:chemistry; D000818:Animals; D018938:Caco-2 Cells; D050091:Dendrimers / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D004285:Dogs; D004337:Drug Carriers / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D061985:Madin Darby Canine Kidney Cells; D010316:Particle Size; D010539:Permeability; D011092:Polyethylene Glycols / Q000737:chemistry; D019108:Tight Junctions / Q000187:drug effects / Q000378:metabolism*
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000578:Amidines; D050091:Dendrimers; D004337:Drug Carriers; C104700:PAMAM Starburst; D011092:Polyethylene Glycols