Preparation and characterization of n-octylamine modified alginate/chitosan microspheres for controlled release of avermectin

Microspheres can be designed to increase the utilization of pesticides and reduce environmental pollution. In this study, the sodium alginate (SA) modified with n-octylamine was prepared, and the microspheres loading avermectin (AVM) were fabricated by orifice-coagulation bath using chitosan and modified/nature SA as the carrier materials. The particle size, granulation ratio, drug loading (DL) rate, embedding rate, swelling and sustained-release properties of microspheres were investigated. The Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterize the structure and morphology of microspheres. The results showed that the swelling and drug release properties of modified and unmodified microspheres showed good pH and thermo responsive. The DL performance of modified microspheres was improved, the embedding efficiency (EE) and DL were up to 60.3% and 75.8%, respectively. Furthermore, the AVM release time of microspheres with modified SA was prolonged and extended up to 48 h. All results indicated AVM of modified microspheres possessed higher utilization efficiency compared to the unmodified microspheres.