Preparation And Drug Loading Performance Of Hierarchical Layered Double Hydroxides Composites

Drug delivery system（DDS） is a delivery way that drugs are administered in a living organism.The concentration of drugs in the blood generally has a low persistence,so the release control agent and the oral long-acting delivery system develop rapidly.The appropriate drug delivery system can reduce adverse reactions and increase the convenience of the patient’s medication.The paper explores the fabrication of drug-loaded layered double hydroxides composites and discusses its release performance.Chitosan（CS） and MgAl-layered double hydroxides（LDHs）were used as predecessors to develop a novel composite core-shell drug carrier by self-assembly and embedding.Baicalein that has anti-inflammatory effect was used as the model drug in this paper.The structures were characterized by X-ray diffraction（XRD）,Fourier transform infrared spectrometer（FTIR）,transmission electron microscope（TEM）and scanning electron micrograph（SEM）.The results showed that the SDS micelle with baicalein was intercalated into LDH interlayer.Then LDH with baicalein coated with chitosan microsphere.The drug loading contents of chitosan-LDHs composite drug carriers reach at 143 mg/g.During 5-12 h,the release mechanism of composite drug carriers conformed to pseudo-first-order.Antibacterial test showed that CS microspheres and LDH have good antibacterial effect.The ZnO with fiber structure is prepared by impregnation-calcination method.Then the ZnAl-LDHs nanoplatelets are fabricated into architectures by in situ growth on the surface of ZnO.During LDHs crystal growth process,different calcined precursors（Zn（NO₃）₂ and Zn（CH₃COO）₂ solution）and different ratios（Zn:Al）were discussed to the influence of morphology of ZnO and LDHs/ZnO.The LDHs/ZnO composites synthesized by optimum ratio of Zn:Al were used to load magnesium salicylate（Mgsa）and niacin.Results showed that LDHs/ZnO-Mgsa and LDHs/ZnO-niacin hybrids in 2 h were nearly completed and a slow progression afterward.LDHs/ZnO-niacin hybrids presented a higher drug loading content than LDHs/ZnO-Mgsa hybrids.Drug-loaded LDHs/ZnO composites with zinc acetate precursor had a higher loading capacity than that with zinc nitrate precursor.The release mechanism of all the drug-loaded hybrids conformed to pseudo-first-order and Higuchi kinetic models.Antibacterial analysis showed that LDHs/ZnO which was prepared by zinc acetate and zinc nitrate as precursor ideal anti-bacterium effect.