Enantioselective resolution of chiral drugs using BSA functionalized magnetic nanoparticles

Bovine serum albumin (BSA) anchored on the surface of magnetic Fe3O4 nanoparticles (MNPs) were prepared using electrostatic adsorption and studied as a new magnetically chiral selector for the separation of chiral drug enantiomers. It is indicated that the immobilized BSA molecules on the magnetic nanoparticles using electrostatic adsorption retain their stereoselective recognition with site II-binding drug ibuprofen at pH 7.0 and site I-binding drug ofloxacin at pH 9.0, with a optimal loading of 467 mg BSA per gram of MNPs. For racemic ibuprofen and ofloxacin, single-stage adsorption gives an enantiomeric excess of 13% and 14%, and the multi-stage operation enhances the chiral performance providing the ee value of 54% and 39% respectively. As increasing the initial ee of enantiomeric mixtures, Δee levels of 50%, 35% and 16% for stronger binder ibuprofen, as well as 31%, 17% and 13% for weaker binder ofloxacin are achieved under the same operational conditions. Depending upon the eutectic point of racemic compound, a hybrid process involving the enrichment of one enantiomer using BSA–PDDA–MNPs followed by subsequent crystallization is proposed to obtain the enantiomer with higher optical purity.

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► BSA modified magnetic nanoparticles are utilized as novel chiral selectors.
► Immobilized BSA exhibit chiral discrimination for ibuprofen and ofloxacin.
► Multi-stage adsorption significantly enhances the enantiomeric excess.
► A hybrid resolution approach is proposed to obtain pure enantiomers.