title: Controlled release of avermectin from porous hollow silica nanoparticles: influence of shell thickness on loading efficiency, UV-shielding property and release.
abstract: Preparation and characterization of porous hollow silica nanoparticles (PHSNs), with various shell thicknesses in the range of 5-45 nm and a pore diameter of about 4-5 nm, were investigated. PHSNs were fabricated via a sol-gel route with two different structure-directing templates and their shell thickness could be controlled by adjusting the reactant ratio of Na2SiO3.9H2O/CaCO3. The produced PHSNs were applied as controlled pesticide release carriers to study the effects of the shell thickness on the loading efficiency for avermectin, the UV-shielding property for the loaded avermectin and the controlled release of the loaded avermectin from the carriers. It was found that the amount of loaded avermectin decreases with the increase of shell thickness, while the UV-shielding property of PHSNs for avermectin is improved as the shell gets thicker. In addition, the shell thickness has a significant impact on avermectin release. Increasing the shell thickness in the range of 5-45 nm leads to a more sustained release by decreasing the release rate of the pesticide from PHSNs, showing that the shell thickness is one of the main controlling factors for the active agent release from such systems.
authors.affiliation: Key Lab for Nanomaterials, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Zhu-Zhu
authors.initials: ZZ
authors.lastname: Li
authors.forename: Shi-Ai
authors.initials: SA
authors.lastname: Xu
authors.forename: Li-Xiong
authors.initials: LX
authors.lastname: Wen
authors.forename: Fan
authors.initials: F
authors.lastname: Liu
authors.forename: An-Qi
authors.initials: AQ
authors.lastname: Liu
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Sun
authors.forename: Wen
authors.initials: W
authors.lastname: Yu
authors.forename: Jian-Feng
authors.initials: JF
authors.lastname: Chen
mesh_terms: D003692:Delayed-Action Preparations / Q000737:chemistry / Q000493:pharmacokinetics*; D004337:Drug Carriers / Q000737:chemistry; D004355:Drug Stability; D007306:Insecticides / Q000737:chemistry / Q000493:pharmacokinetics; D007559:Ivermectin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000493:pharmacokinetics; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D007306:Insecticides; D007559:Ivermectin; C019264:avermectin; D012822:Silicon Dioxide