Estrutura supramolecular entre 2-hidroxipropil-β-ciclodextrina e citral potencializa a atividade contra Rhipicephalus microplus (Acari: Ixodidae)

Abstract

Rhipicephalus microplus is responsible for significant damage to global livestock, and the control of this parasite faces barriers such as acaricide resistance. Citral (CIT) is a potential acaricide; however, due to characteristics such as low volatility and water dispersibility, its field application is limited. The objective of this study was to prepare, characterize, and evaluate, in vitro, the acaricidal activity of the complex containing citral and 2-hydroxypropyl-β-cyclodextrin on R. microplus larvae. The complex (CIHβCIT) by kneading and the physical mixture (MFHβCIT) were prepared in a stoichiometric ratio of 1:1, confirmed by the solubility diagram and the Job Plot method. The intermolecular interaction between CIT and HPβCD was indicated, suggesting complex formation, confirmed by FTIR-ATR, TGA/DTG, DSC, XRD, and SEM. The kneading preparation method produced CIHβCIT with high yield (90.60%), encapsulation efficiency (72.03%), and drug loading of 6.48%. These parameters were determined through UV-Vis spectroscopy. The LC50 values obtained by the larval packet test for CIT, CIHβCIT, and MFHβCIT were 0.66%, 1.13%, and 1.16% (w/v), respectively. The formation of CIHβCIT reduced the volatility of CIT, maintaining acaricidal activity (81.59%) over 48 hours, compared to free CIT (64.61%) and MFHβCIT (60.86%). Thus, the preparation of CIHβCIT through the kneading technique is capable of enhancing and ensuring the acaricidal activity of CIT for an extended period