Microencapsulation of citronella oil by electrospray to increase repellency time against mosquitoes

PARDINI, FRANCISCO; HORMAIZTEGUI, MARÍA; MUTTIS, E.; BRIVIDORO, MELINA V.; MICIELI MARIA VICTORIA; FACCIA, PAULA

Rosario

Jornada; 7 ma reunión internacional de Ciencias Famaceúticas; 2023

Introduction:The use of natural oils as insect repellents has several advantages over synthetic repellents. However, the protection time is short due to its high volatility. Therefore, its application must be optimized to achieve a more lasting and effective effect. In this sense, encapsulation of essential oils in low-cost and biodegradable polymers emerges as an alternative strategy. Electrospray (EP), as an encapsulation method, is a versatile, effective, simple technique and is therefore suitable for incorporating natural oils into polymeric matrices. This work then proposes the preparation of microcapsules (MC) of Poly--Caprolactone (PCL) with citronella oil (C) using the EP method, to evaluate the percentage of repellency against mosquitoes over time.Experimental: By applying a certain voltage (10 kV), homogeneous polymer/oil solutions were electrosprayed to obtain polymer/oil microcapsules. The flow of the polymer solution (0.5 mL/h) was regulated with an injection pump and the particles were collected on a metal collector. The process was evaluated by means of microscopy (optical, SEM) and infrared spectroscopy. The encapsulation efficiency (EE) was calculated by HPLC for each proportion tested using equation 1.EE =(Mt-Me)/Mt x100 Eq. 1Where Mt and Me are the theoretical and experimental oil masses respectively.The repellency tests were carried out in the CEPAVE insectary with Aedes aegypti mosquitoes. An ethanol/water lotion with the CM was applied to one arm, on a delimited surface of 75 cm2 (5 x 15). The repellency percentage (R%) was calculated using equation 2:R (%) = [(C – T)/C]x100 Eq. 2where C and T are the number of mosquitoes that rest on or bite the control arm and the treated arm respectively.