Preparation Of ZnAl-LDH@SiO₂ And Study On The Double Drug Release Behavior

The nano-core-shell structure is a material formed by one nano-material coating on another nano-material.These two parts play the role of supporting and protection,respectively.The core-shell structure materials can integrate performance of the two parts and play a certain role that one single part does not have.Its research and application are of great significance to drug carriers and release.In this paper,a dual drug sustained-release system with IBU intercalated LDH as core and mSiO₂ and its derivatives as shell was prepared,in order to prepare a drug sustained-release system in which core layer and shell layer are loaded with different drugs,respectively.Firstly,co-precipitation method was used to prepare layered double hydroxide intercalated with ibuprofen?IBU-LDH?.Then three core-shell structures IBU-LDH@SiO₂,IBU-LDH@?SiO₂+SiO₂-NH₂?,IBU-LDH@SiO₂-NH₂ were prepared using IBU-LDH as core and dense SiO₂ layer,mSiO₂ with high or low amino content coating on the core.The effects of partial exfoliation of IBU-LDH,coating conditions for the shell layer,feeding ratio between shell and core materials on the structure of core-shell structure and its drug sustained release were studied.The results showed that the samples prepared had a core-shell structure with a hexagonal sheet-like morphology as the hydrolytic medium was the volume ratio of formamide:deionized water=1:2 and the pH of the encapsulation solution was 8.Polyhedral oligomeric silsesquioxane is formed in the shell layer of IBU-LDH@SiO₂-NH₂,which has obvious pore structure.Its pore diameter is 3.5 nm,the specific surface area is 100.00 m²/g.Under the same conditions,the release amounts of the drugs in the shell layer of the three drug carriers are:IBU-LDH@SiO₂-NH₂>IBU-LDH@?SiO₂+SiO₂-NH₂?>IBU-LDH@SiO₂.In terms of release rate,the drug release rate of IBU is slower than that of ferulic acid?FA?.In the three structures,more than 70%of FA release out within 30 minutes,while IBU takes 60 minutes or longer.IBU-LDH@SiO₂-NH₂ can achieve the step-by-step release of two drugs.On the base of the above results,the structure of LDH@SiO₂-NH₂ was optimized,the effects of the materials feeding ratio for core-shell layer and encapsulation method on the target products'structure and the drug release of the optimum structure were studied.The results showed that when shell material m _APTES+TEOS=0.6 g,APTES:TEOS=20:4,and the outside is further encapsulation with dense SiO₂,the drug loading and release of the drug on the shell can be further increased and reduced respectively.Even more drug release equilibrium time can be extended to 80 minutes.