Study On The Preparation And Performance Of 1,3-Diacylglycerol Based Solid Lipid Nanoparticles

Since the solid lipid nanoparticles(SLN)can remarkably improve the dispersibility and solubility of hydrophobic molecules in water,it has been widely used in the food,health care,pharmacology,cosmetics and some other fields.The lipid matrixes used for the preparation of traditional SLN are mainly mono-glycine,triglycerides,fatty acids,sterols and steroids,however,using diacylglycerol as lipid matrix to prepare SLN had been rare reported.In this study,1,3-diacylglycerol which is a kind of structured lipid with good physiological properties was applied to the lipid nanoparticles system as lipid matrix.Two new types of drug delivery systems were established,and the drug-loading performance were evaluated by loading thymol as a template molecule.The significant advantage of1,3-diacylglycerol based SLN had been proved by comparing the drug-loading performance between traditional SLN and 1,3-diacylglycerol based SLN.The main research content and related conclusions are summarized as follows:(1)With the stabilization of tween 80 and soybean lecithin,a stable and homogeneous1,3-DAG-SLN dispersion was successfully prepared by microemulsion method,and the mean size of the SLN dispersion was 264±0.69 nm,PDI value was 0.16±0.03,and zeta-potential was-12.5±1.13 mV.Subsequently,the study on the thymol-loading performance showed that the maximum loading capacity was 16%,but the most suitable loading capacity was no more than 4%,meantime,the thymol-loading SLN system was very stable,and no leakage occurred during storage.using the morphology characterization of TEM,it was proved that the thymol-loaded SLN dispersion had very good dispersibility,and the particles was in a regular spherical shape.FTIR and fluorescence spectra both showed that thymol was fully encapsulated into the SLN.The slow-release study showed that 1,3-DAG-SLN dispersions possessed good controlled-release performance.(2)The condition which can be used to prepare 1,3-DAG,Glycerol monostearate and palmitic triglyceride based SLN was optimized.The optimal condition is as follows: lipid(80 mg),lipid/surfactant=1:3,SL/TW80=3:1,water(2 g),ethanol(0.5 mL).The thymol-loading performance showed 1,3-DAG possessed the best loading capacity between these three kinds of lipid matrix with the most suitable loading capacity of 16%.XRD study demonstrates that the main crystal form of 1,3-DAG is ? crystal,and there is no crystal transformation during the storage,while the other two types of lipids have been transformed from ?-crystalline form to more ordered ?-crystalline form,which can cause the drug leakage during the storage.(3)Under the optimal condition,the mean particle size,PDI,and zeta-potential of the 1,3-DAG-NLC dispersion was 225±4.94 nm,0.16±0.01,and-19.1±0.59 mV,respectively.The maximum drug-loading capacity was 24%,and the most suitable loading capacity is no more than 20%,which has no significant change of the particle sizes after the loading of thymol.further characterization of TEM,FTIR and fluorescence spectra showed that both the SLN and NLC have good loading performance,and the dispersions had uniform and stable particle size distribution.In addition,the evaluation of different solid-liquid lipid ratio on the fluorescence spectra of thymol loaded NLC showed the higher ratio of liquid lipid,the better dispersion and freedom of thymol in the lipid.The results showed that the optimal ratio of solid-liquid lipid was DAG/SFO=4:1,and there was no significant difference in loading stability compared with 1,3-DAG-SLN system.However,1,3-DAG-NLC system had better drug-loading capacity and smaller particle size,meanwhile,the slow-release performance may be worse with the increase of liquid lipid ratio indicated by fluorescence spectra.