Preparation And Enantioselective Release Property Of Porous Materials Constructed By Chiral Polymers

Recently,enantio-pure compounds have been intensively studied in the fields of medicine and pesticides.We need to get one of the enantiomeric drugs with favorable pharmaceutical effects especially after the occurrence of"thalidomide incident".Nowadays several methods have been developed to separate drug enantiomers to obtain enantiomerically pure compounds,including fermentation technique,asymmetric synthesis and the separation of enantiomers by HPLC.However,these methods show some inherent disadvantage.For example,chiral compounds can be obtained in low yield from fermentation technique.Furthermore,these methods also have the deficiency of complex condition and high cost.Therefore,simple but effective methods are still urgent to be found to get optically pure compounds.Enantioselective release might provide novel altermatives for realizing selective administration of the preferred stereoisomer.Due to the pore structure of hydrogels and polyHIPEs,small molecules can be adsorbed and released along with the solvents.In this study,chirality was introduced into hydrogels and polyHIPEs to achieve enantioselectively release.The main works are as follows:Firstly,two types of hydrophilic acetylene molecules(FA,PAm)were synthesized and used as comonomer to prepare helical polyacetylene(HPA)bearing polymerizable vinyl group.Taking advantage of the hydrophilic and polymerizable moieties,HPA was further used as macromer to prepare hydrogels in deionized water via free radical polymerization,using N-isopropylacrylamide(NIPAm)as comonomer.The as-perpared hydrogels exhibited thermo-sensitivity,optical activity and biocompatibility.In particular noticeably,the chiral hydrogels showed enantio-differentiating release ability towards mandelic acid enantiomers and prolines enantiomers which were used as chiral compound models.Secondly,chiral monomers were synthesized with Boc-alanine(D or L)and HE A through esterification reaction.FT-IR and 1H NMR indicated the successful preparation of designed chiral monomers.Then the obtained chiral monomers were further used to prepare porous materials through high internal phase emulsion(HIPE)template method.The as-prepared polyHIPEs were deprotected to make amino groups accessable for applications.The chiral polyHIPEs exhibited optical activity and good thermo-stability.Meanwhile,the polyHIPEs demonstrate typical pore structures which were observed by SEM images.The chiral polyHIPEs showed enantio-differentiating release ability towards chiral drugs,using naproxen enantiomers as chiral compound models.More interestingly,the two types of chiral polyHIPEs possessed the opposite optical activity but showed some enantioselectivity towards the same chiral drug,i.e.preferably releasing R-naproxen over the S enantiomer.