Novel worm-like amphiphilic micelles of folate-targeted cyclodextrin/retinoic acid for delivery of doxorubicin in KG-1 cells

Folate-targeted cyclodextrin/retinoic acid (CD/RA) conjugate was synthesized using carbonyldiimidazole (CDI) and dimethylaminopyridine (DMAP). The structure of the produced macromolecule was studied by FTIR and (HNMR)-H-1. The developed macromolecule could self-aggregate to form micelles. Critical micelle concentration (CMC) of the macromolecule was determined by pyrene as a fluorescent probe. Doxorubicin (DOX)-loaded micelles were prepared by direct dissolution method. To optimize the effect of cyclodextrin type (alpha or beta), the molar ratio of RA to CD and the drug content, a full factorial design was used and their effects on particle size, polydispersity index, zeta potential, loading efficiency (LE%), and release efficiency (RE24%) in 24 h were studied. Orientation of folate ligand on the surface of the micelles was studied by X-ray photoelectron spectroscopy (XPS) technique. The cytotoxicity of DOX-loaded micelles was studied on KG-1 cells which overexpressed folate receptor (FR) and FR-negative HepG2 cells using MTT assay. FTIR and (HNMR)-H-1 spectra confirmed successful production of the micelles and XPS spectra showed surface orientation of folate. The best results obtained from beta-cyclodextrin with molar ratio of 4 to RA and 15 % drug content. The optimized micelles showed the particle size of 103 +/- 4 nm, zeta potential of -36 mV, polydispersity index of 0.28 +/- 0.05, LE% of 100 %, and RE24% of 69.88 +/- 1.6 %. The IC50 of targeted micelles was half of non-targeted micelles and free DOX.