Development and characterization of electrosprayed microcaspules of poly ε-caprolactone with citronella oil for mosquito-repellent application

Several life-threatening diseases such as malaria, dengue or zika are transmitted by mosquito bites. Although there are several products available for personal protection against mosquitoes, the adequate efficacy of natural insect repellents (NIR) or the adverse effects of synthetic ones are problems that need to be solved. The encapsulation of NIR in low-cost, nontoxic and biodegradable polymers has emerged as a promising method for the development of eco-friendly repellent systems.In this work, the encapsulation of citronella oil (CO) into microcapsules of poly (ε-caprolactone) (PCL) was made by electrospraying technique to obtain a system that shows a sustained release of the high volatile oil. Characterizations of the capsules were performed by NMR, FTIR, SEM and DSC techniques. CO encapsulation efficiency (EE) and release studies were also determined by using HPLC technique.Results demonstrated that a 3/1 PCL-CO ratio and 10 kV were the best conditions to obtain regular and well-formed microcapsules. Characterization techniques showed the presence of CO in the microcapsules with an EE higher than 80%. Release studies in water solution indicated a sustained CO liberation for at least forty days. The present study shows the strong potential of the PCL-CO microcapsules as an effective and sustained release system with potential application in protection against mosquitoes. These microcapsules are not considered microplastics due to their biodegradable character and therefore their use is not restricted by the different legislations.