Controlled release of avermectin from porous hollow silica nanoparticles

Abstract Porous hollow silica nanoparticles (PHSNs) with a diameter of ca 100 nm and a pore size of ca 4.5 nm were synthesized via a sol–gel route using inorganic calcium carbonate nanoparticles as templates. The synthesized PHSNs were subsequently employed as pesticide carriers to study the controlled release behaviour of avermectin. The avermectin‐loaded PHSN (Av‐PHSN) samples were characterized by BET, thermogravimetric analysis and IR, showing that the amount of avermectin encapsulated in the PHSN carrier could reach 58.3% w/w by a simple immersion loading method, and that most of the adsorption of avermectin on the Av‐PHSN carrier might be physical. Avermectin may be loaded on the external surface, the pore channels in the wall and the inner core of the PHSN carriers, thus leading to a multi‐stage sustained‐release pattern from the Av‐PHSN samples. Increasing pH or temperature intensified the avermectin release. Copyright © 2005 Society of Chemical Industry