Alkyl glycol chitosan derivatives for encapsulation and controlled release of rotenone

Abstract

Rotenone is a hydrophobic organic compound with the excellent insecticidal property. However, its hydrophobicity and the short period of efficacy due to rapid degradation in the presence of UV light and air have limited its application as an insecticide. This study studied the effects of hydrophobic alkyl groups on encapsulation and controlled release of rotenone by amphiphilic chitosan derivatives namely, octyl glycol chitosan (OGC) and lauryl glycol chitosan (LGC) were assessed. The physical and chemical properties of OGC and LGC were characterized using Fourier Transform Infrared (FTIR) Spectrometer, CHNO Elemental Analyzer, UV-Visible Spectrophotometer, Fluorescence Spectrofluorometer, and Differential Scanning Calorimetry (DSC). The efficiency of OGC and LGC to encapsulate for rotenone in its micelles was determined by using a High-Performance Liquid Chromatography (HPLC). FTIR and CHNO elemental analyses confirmed the amphiphilic chitosan derivatives were successfully synthesized using the reverse micelles method. The finding from the solubility study shows that the addition of the glycol group to the chitosan backbone has enhanced chitosan’s solubility properties in neutral and basic media. OGC and LGC exhibited good affinity towards rotenone with an encapsulation efficiency of more than 90%. The in vitro release study showed that the OGC and LGC could control the release of rotenone from its micelles. This study demonstrates that OGC and LGC showed beneficial properties to be further developed as a potential carrier in the pesticide formulation.