Formulation of geranium oil loaded solid lipid nanoparticles for mosquito repellent application

Abstract

In recent years, essential oil has been the subject matter of many investigations due to its eco-friendly and bio-degradable nature. Geranium oil is one of the various essential oils that are used as mosquito repellent. However, stability is one of the issues related to essential oil fonnulations. Incorporation of essential oil in a control-release formulation could solve the problem and it also offers several advantages. In this work, a new delivery system for mosquito repellent based on the incorporation of geranium oil into solid lipid nanoparticles (SLNs) has been studied. The following has been employed for the production of geranium oil loaded solid lipid nanoparticles (GO-SLNs): 5-15% (w/w) stearic acid as the lipid, 0.5-3% (w/w) soy lecithin as the emulsifier, 0.5-3% (w/w) Tween 80 as the co-emulsifier, 5-20% (w/w) dichloromethane also as the co-emulsifier and 8% (w/w) geranium oil as the active ingredient. GO-SLNs were prepared using ultrasonicsolvent emulsification technique. GO-SLNS were characterized using transmission electron microscopy (TEM), photon cross correlation spectroscopy (PCCS), gel filtration and gas chromatography (GC). Results showed that the variation in the amount of ingredients affected geranium oil loading capacity and mean particle size. Increasing the concentrations of lipid, emulsifier and co-emulsifier resulted in the increase in the mean particle size from 46 nm to 114 nm. Geranium oil encapsulation efficiency (EE) was in the range of 92-99% (w/w). Production of high quality SLNS loaded with geranium oil has been demonstrated.