Design of dehydroabietylamine-modified β-cyclodextrin adsorbents for the highly efficient chiral separation of valsartan enantiomers

The separation of enantiomers is crucial in the pharmaceutical industry. Herein, a novel polymeric adsorbent was developed through the single-step cross-linking of [6-DHAA-6-deoxy]-β-CD, a dehydroabietylamine (DHAA) modified β-CD using epichlorohydrin. The resulting polymer demonstrates exceptional chiral recognition for the S-enantiomer of valsartan, a model chiral pharmaceutical, with a high adsorption capacity 20 mg·g −1 at 25 °C. Thermodynamics and kinetics studies reveal that S -valsartan adsorption onto poly-[6-DHAA-6-deoxy]- β -CD follows the Langmuir isotherm model and the pseudo-second-order kinetics, respectively. Molecular simulations suggest that chiral recognition arises from differing orientations and specific binding energies of the two enantiomers on the [6-DHAA-6-deoxy]-β-CD host. Under optimized conditions, racemic valsartan is successfully resolved with an excellent enantiomeric excess, leading to a high enantiopurity of 99.5% for the S -valsartan product. The current study not only presents a high–performance adsorbent for the enantioseparation of valsartan enantiomers, but more importantly, outlines a versatile pathway for developing sustainable separation media from natural, chiral resources.