Solid lipid particles in lipid films to control the diffusive release of 2-heptanone.

Controlled-release formulations of bioactive agents are of increasing interest for effective pest control. Volatile 2-heptanone is a bioactive agent that has shown potential as a pesticide. The aim of this study was to investigate the kinetics of release of 2-heptanone incorporated into lipid films or composite solid lipid particle (SLP) films. Effective 2-heptanone diffusivity was estimated to be between 0.1 and 2.5 mm(2)  day(-1) during the first week and between 0.05 and 0.1 mm(2)  day(-1) during the next 5 weeks. The films that showed better retention of 2-heptanone were the paraffin lipid films. Inclusion of SLPs into paraffin films increased the release rate of 2-heptanone, mainly owing to a decrease in the film firmness as the composite SLP film became less crystalline and more brittle. In contrast, SLPs decreased the kinetics of 2-heptanone release in Acetem films owing to an increase in the film firmness. The results indicated that the use of SLPs as a method for controlled release can improve the delivery of the natural pesticide 2-heptanone if the SLPs have good compatibility with the matrix, leading to an increase in firmness of the films without increasing their porosity. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.