Synthesis Of β-cyclodextrin-incorporated Polyurethane Copolymers Forcontrolled Release Of Protein And Doxorubicin

A series of amphiphilic polyurethane (PU) copolymers were synthesized by condensationreaction of poly(ethylene glycol)(PEG) of different molecular weights and1,6-hexamethylene diisocyanate (HDI), with/without end-cappedheptakis(2,6-di-O-methyl)-β-cyclodextrin (DM-β-CD). Their chemical structures werecharacterized by Fourier transform infrared spectroscopy and proton nuclear magneticresonance spectroscopy. Their molecular weights, thermal properties and crystallizationproperties were investigated using gel permeation chromatography and differential scanningcalorimetry, respectively.A model protein, bovine serum albumin (BSA), was encapsulated into the PU reversemicelles (RMs) with/without DM-β-CD entities using emulsification method indichloromethane (DCM), and then further transferred in biocompatible oil, i.e., ethyl oleate.The diameter of RMs in DCM decreased upon heating, as determined by dynamic lightscattering (DLS), and was spherical in shape as observed by scanning electron microscope.The encapsulation efficiency (EE) and loading capacity (LC) of BSA in the RMs composed ofDM-β-CD-contained PUs were much higher than those without DM-β-CD. In vitro releasestudies showed that the release rate of RMs of DM-β-CD-contained PUs was faster than theircounter parts without DM-β-CD. Interestingly, among all the RMs in the present study, theRMs of DM-β-CD-contained PU composed of the irregular segments of both PEG1000andPEG2000exhibited the highest EE and LC, and the fastest release rate of its cargo. Theseresults highlight the ability of RMs of proper PUs composition to act as carriers for protein inan oleous phase with good EE and proper release behavior, paving a new way for theapplication of PU-based RMs in protein or peptide delivery.The PUs were then used for preparation of doxorubicin-loaded nanoparticles by dialysismethod.All PUs samples had strong ability of encapsulating doxorubicin, exhibiting fastrelease at pH5. The release rate of H-Mw polyurethanes is significantly faster than L-Mwpolyurethanes.