Long-acting Release Of Active Molecule By Using LDH-based Materials

The technology of controlled release of active molecules has been widely used in chemical production,food preservative,drug delivery in vivo and so on.At present,in the report of long-acting sustained release technology,polymer films and nanoparticles are the most common materials.However,there are two problems in their practical application:One is the short release time;Another problem is the presence of severe initial-burst release.Aiming at the core problems in the above fields,the following two systems are designed:1.Two kinds of sustained release films were prepared,using methyl orange（MO）as a target release substance and LDH as barrier material.B-MO@polymer film was obtained by embedding of MO into polylactic acid/polyethylene glycol（PLA/PEG400）substrate and then assembling LDH/carboxymethyl chitosan（CMC）barrier layer on the substrate surface by spin-coating technique.LDH&MO@polymer film was prepared by co-incorporation of LDH and MO into the PLA/PEG400 polymer matrix through a blending coating technology.Both of these two films have high loading capacities of～500μg/cm² for MO,and display long-acting and sustained-release property.When the barrier layer LDH/CMC is 30 layers,B-MO@polymer film has the best sustained release performance,and its sustained release time can be extended to 60 days.In addition,LDH_10%&MO@polymer film and B₃₀-MO@polymer film in 0.06 mol/L Mg²⁺solution can achieve zero-order release dynamics for MO,which solves the problem of initial-burst release in the early stage,and the continuous release time can reach 120 days and 140 days,respectively.Finally,B-MO@polymer film has strong controllability and adjustability,while LDH&MO@polymer film is simpler and easier to achieve industrial production in preparation process.Both films provide long-term release by changing the loading of active molecules and have promising applications in chemical engineering and drug therapy.2.Sodium dichlorophenate（DIC）intercalated MgAl-LDH was prepared by single drop co-precipitation method,and its general molecular formula was determined as[Mg_0.678Al_0.323（OH）₂]（DIC）_0.233（NO₃）_0.0193（CO₃）_0.0911·1.79H₂O by ICP,TGA,elemental analysis and calculation,with a DIC loading of 41.24%.Next,the 0.1%LDH-DIC was added to Pluronic F-127（P.F-127）solution as a sustained-release drug to make eye drops.The appropriate concentration of P.F-127 in eye drops was determined to be 12.5%by viscosity testing.The release performance of DIC in eye drops can be extended to more than 24 hours by UV-vis test.The sustained release mechanism of DIC is diffusion release and ion exchange release by comparing the sustained release properties of different solutions.Furthermore,P.F-127 controlled the release of DIC and maintained the equilibrium concentration of DIC in eye drops at 60μg/m L.In addition,corneal fluorescein sodium staining and PAS staining experiments verified that the therapeutic effect of the eye drop on dry eye was superior to pure DIC,which greatly reduced the infiltration of inflammatory cells and corneal conjunctiva damage.The long-acting sustained release performance of the eye drops is better than that reported in most literatures,which reduces the trivialization of patients’frequent drug ordering,increases the tolerance and compliance of patients,and has a good application prospect.