Research On Preparation And Characteristics Of Drug-loaded Magnetic Layered Double Hydroxides

Hydrotalcite is a kind of layered double hydroxides（LDH）,which has good biocompatibility,degradability,and very low biotoxicity.Its unique bilayer structure allows it to be used as a drug carrier to control the release of drugs.In recent years,the research focus in the field of medicinal minerals is to prepare magnetic drug carriers with magnetic targeting function and stable structure,which can further inhibit the toxic side effects of drugs on the body.Based on this,LDH was selected as the drug carrier material,non-steroidal drug ibuprofen（IBU）was the target drug.Aiming at the problems of poor adsorption performance and low adsorption efficiency of LDH on IBU,the"memory effect"of LDH was used to calcinate it to enhance its adsorption performance to IBU.At the same time,calcined magnetic layered double hydroxides（CMLDH）with magnetic targeting function were prepared by adding an iron source,and its adsorption and release experiments on ibuprofen were conducted to study its adsorption and release behavior.The main research conclusions were as follows:（1）Hydrotalcite（LDH-120）with single phase and good thermal stability can be prepared by homogeneous hydrothermal synthesis at 120℃.Calcined magnetic hydrotalcite No.2 sample（CMLDH-2）was prepared by calcination method at LDH-120:Fe₂O₃=8:2（mass ratio）and calcination temperature of 350℃.Magnetic particles（γ-Fe₂O₃）were attached to its surface by electrostatic adsorption.Calcined magnetic hydrotalcite No.2sample could recover its typical layered structure of hydrotalcite through the"memory effect"in water,Na Cl solution（mass fraction:0.9%）,and Na OH solution（concentration:1mol/L）.（2）Calcined magnetic hydrotalcite can realize the rapid adsorption of ibuprofen.Under the condition of the adsorption solution is 6 and the solid-liquid ratio is 1,the IBU-loaded magnetic hydrotalcite（MLDH-IBU）with an adsorption capacity of 235.04 mg/g can be obtained.The adsorption of ibuprofen by calcinated magnetic hydrotalcite was monolayer adsorption,which was consistent with the Langmuir isothermal adsorption model.The adsorption kinetics of ibuprofen conformed to the pseudo-second-order kinetic model,that is,it was mainly controlled by chemical interaction.Ibuprofen combined with Al³⁺in the hydrotalcite structure through the carboxyl group and showed a slanted bilayer arrangement,which increased d₀₀₃from 0.756 nm to 2.266 nm,and the product always maintained a typical hexagonal sheet structure.（3）In the release medium of phosphate buffer solution（PBS）and Na Cl solution,the IBU-loaded magnetic hydrotalcite released ibuprofen mainly through anion exchange between layers.The maximum release of ibuprofen in phosphate buffer solution was about65%,while it showed a sustained release behavior with a gradually decreasing release rate in Na Cl solution.The fitting results of the modified pseudo-first-order kinetic model showed that the amount of ibuprofen adsorbed on the surface of IBU-loaded magnetic hydrotalcite was low,and most of the ibuprofen adsorbed between the layers of hydrotalcite.