Oleic acid

Lippia sidoides EO was purchased from PRONAT (Produtos Naturais do Nordeste LTDA, Horizonte, Ceará, Brazil). The constituents of the NLCs were Gelucire 50/13 (Gattefossé, Saint-Priest, France), oleic acid (LabSynth, Diadema, São Paulo, Brazil), Labrasol (Gattefossé, Saint-Priest, France), Span^® 80 (Sigma-Aldrich, Darmstadt, Germany), Tween^® 80 (LabSynth, Diadema, São Paulo, Brazil), and Poloxamer 188 (Kolliphor P 188 Micro, kindly donated by BASF, Ludwigshafen, Germany). Mixtures of whey protein (Arla Foods Ingredients S.A., Buenos Aires, Argentina), arabic gum (Nexira, São Paulo, Brazil), and colloidal silicon dioxide (Aerosil 200, Evonik Degussa, Essen, Germany) were used as spray-drying carriers. ultrapure water (Direct Q System, Millipore, Merck KGaA, Darmstadt, Germany) was used in the preparation of NLCs. Other chemicals and solvents used were of pharmaceutical or of high performance liquid chromatography (HPLC) grade.

Thymol, sodium dodecyl sulfate, and acetonitrile HPLC grade were purchased from Sigma–Aldrich (St. Louis, MO, USA). L. sidoides EO, distilled from fresh leaves, was purchased from Pronat (Produtos Naturais LTDA, Horizonte, Brazil). Methanol and oleic acid were purchased from Labsynth (Vinhedo, Brazil). Compritol^® 888 ATO (Gattefossé, Saint-Priest, France—melting range from 65 °C to 77 °C), Carnauba wax (Foncepi, Fortaleza, Brazil—melting range from 80 °C to 86 °C), and Beeswax (Via Farma, São Paulo, Brazil—melting range from 61 °C to 65 °C) were the solid lipids used. The NLCs constituents—solid lipids: Compritol^® 888 ATO, Carnauba wax and Beeswax; liquid lipid: oleic acid; and surfactant: sodium dodecyl sulfate—are generally recognized as safe substances (GRAS/FDA listed) for use in various pharmaceutical, cosmetics and food products at concentrations used in this work [27 (link),28 (link),29 ]. More detailed and updated information regarding these substances, including CAS registry number, main physicochemical properties, applications, safety, regulatory status, among others, are presented in Sheskey et al. [29 ].