Stearic acid, beeswax and carnauba wax as green raw materials for the loading of carvacrol into nanostructured lipid carriers

The use of lipid nanoparticles as drug delivery systems has been growing over recent decades. Their biodegradable and biocompatible profile, capacity to prevent chemical degradation of loaded drugs/actives and controlled release for several administration routes are some of their advantages. Lipid nanoparticles are of particular interest for the loading of lipophilic compounds, as happens with essential oils. Several interesting properties, e.g., anti-microbial, antitumoral and antioxidant activities, are attributed to carvacrol, a monoterpenoid phenol present in the composition of essential oils of several species, including Origanum vulgare, Thymus vulgaris, Nigellasativa and Origanum majorana. As these essential oils have been proposed as the liquid lipid in the composition of nanostructured lipid carriers (NLCs), we aimed at evaluating the influence of carvacrol on the crystallinity profile of solid lipids commonly in use in the production of NLCs. Different ratios of solid lipid (stearic acid, beeswax or carnauba wax) and carvacrol were prepared, which were then subjected to thermal treatment to mimic the production of NLCs. The obtained binary mixtures were then characterized by thermogravimetry (TG), differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS) and polarized light microscopy (PLM). The increased concentration of monoterpenoid in the mixtures resulted in an increase in the mass loss recorded by TG, together with a shift of the melting point recorded by DSC to lower temperatures, and the decrease in the enthalpy in comparison to the bulk solid lipids. The miscibility of carvacrol with the melted solid lipids was also confirmed by DSC in the tested concentration range. The increase in carvacrol content in the mixtures resulted in a decrease in the crystallinity of the solid bulks, as shown by SAXS and PLM. The decrease in the crystallinity of lipid matrices is postulated as an advantage to increase the loading capacity of these carriers. Carvacrol may thus be further exploited as liquid lipid in the composition of green NLCs for a range of pharmaceutical applications.This work was funded by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq/Brazil), the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES/Brazil, FinanceCode 001), by the Portuguese Science and Technology Foundation (FCT/MCT) and European Funds (PRODER/COMPETE) under the projects M-ERA-NET/0004/2015 and UIDB/04469/2020 (strategic fund), co-financed by FEDER, under the Partnership Agreement PT2020.info:eu-repo/semantics/publishedVersio

X-ray powder diffraction at the XRD1 beamline atLNLS

Various upgrades have been completed at the XRD1 beamline at the Brazilian synchrotron light source (LNLS). The upgrades are comprehensive, with changes to both hardware and software, now allowing users of the beamline to conduct X-ray powder diffraction experiments with faster data acquisition times and improved quality. The main beamline parameters and the results obtained for different standards are presented, showing the beamline ability of performing high-quality experiments in transmission geometry. XRD1 operates in the 5.5-14keV range and has a photon flux of 7.8 x 10(9)photonss(-1) (with 100mA) at 12keV, which is one of the typical working energies. At 8keV (the other typical working energy) the photon flux at the sample position is 3.4 x 10(10)photonss(-1) and the energy resolution E/E = 3 x 10(-4).Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPEM, Lab Nacl Luz Sincrotron, BR-13083970 Campinas, SP, BrazilUNIFESP, ICT, BR-12231280 Sao Jose Dos Campos, SP, BrazilUniv Fed Campina Grande, Unidade Acad Fis, BR-58429900 Campina Grande, PB, BrazilInstituto de Ciência e Tecnologia (ICT), Universidade Federal de São Paulo (UNIFESP), São José dos Campos, SP 12231-280, BrazilWeb of Scienc

Praziquantel-solid lipid nanoparticles produced by supercritical carbon dioxide extraction: physicochemical characterization, release profile, and cytotoxicity

Solid lipid nanoparticles (SLNs) can be produced by various methods, but most of them are difficult to scale up. Supercritical fluid (SCF) is an important tool to produce micro/nanoparticles with a narrow size distribution and high encapsulation efficiency. The aim of this work was to produce cetyl palmitate SLNs using SCF to be loaded with praziquantel (PZQ) as an insoluble model drug. The mean particle size (nm), polydispersity index (PdI), zeta potential, and encapsulation efficiency (EE) were determined on the freshly prepared samples, which were also subject of Differential Scanning Calorimetry (DSC), Fourier-Transform Infrared Spectroscopy (FTIR), drug release profile, and in vitro cytotoxicity analyses. PZQ-SLN exhibited a mean size of ~25 nm, PdI ~ 0.5, zeta potential ~−28 mV, and EE 88.37%. The DSC analysis demonstrated that SCF reduced the crystallinity of cetyl palmitate and favored the loading of PZQ into the lipid matrices. No chemical interaction between the PZQ and cetyl palmitate was revealed by FTIR analysis, while the release or PZQ from SLN followed the Weibull model. PZQ-SLN showed low cytotoxicity against fibroblasts cell lines. This study demonstrates that SCF may be a suitable scale-up procedure for the production of SLN, which have shown to be an appropriate carrier for PZQ.This research was funded by Coordenação Aperfeiçoamento de Pessoal de Nivel Superior (CAPES), Fundação de Amparo à Pesquisa do Estado de Sergipe (FAPITEC), and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, #443238/2014-6, #470388/2014-5). This work was also financed through the project M-ERA-NET/0004/2015, from the Portuguese Science and Technology Foundation, Ministry of Science and Education (FCT/MEC) from national funds, and co-financed by FEDER, under the Partnership Agreement PT2020.info:eu-repo/semantics/publishedVersio

Citrus sinensis essential oil-based microemulsions: green synthesis, characterization, and antibacterial and larvicide activities

The aim of this study was the development and characterization of a new microemulsion composed of sweet orange (Citrus sinensis L.) essential oils (EOCs) and evaluate its antibacterial and larvicide profiles. The optimal combination of EOCs, surfactant (Kolliphor EL), and water was achieved using a ternary phase diagram. EOCs were obtained from orange peel by steam-distillation and analyzed by gas chromatographmass spectrometer (GC-MS). A total of 25 compounds were identified, among which 90 wt % was d-limonene. In order to determine antimicrobial activity of the formulation, minimum inhibitory concentration (MIC) assay was done. d-Limonene, limonene 1,2-epoxide, and -mircene showed a high antibacterial activity. Cell viability studies were performed in L929 murine fibroblast as a cellular line, using the MTT assay. A cell viability of 118% for EOCs and 117.7% for microemulsion after 72 h was recorded indicating no relevant cytotoxic effect. In vivo studies, based on a wax moth, Galleria mellonella (G. mellonella), larvae as a model system showed 100% of larvae mortality under the influence of the microemulsion with EOCs, while a second efficiency rating of 45% for larvae mortality was reached for pure EOCs. These tests confirm a strong larvicide activity for the essential oil, characterized by the highest concentration of limonene as the larvicide agent. The loading of EOCs into microemulsions offered an improved approach for the delivery of this oil which retained its bioactivity, as shown in vitro and in vivo.Financial support provided by Banco do Nordeste (FUNDE-CI/2017.0014) and by the Portuguese Science and Technology Foundation, Ministry of Science and Education (FCT/MEC) through national funds, and was cofinanced by FEDER under the Partnership Agreement PT2020 within the frame of the strategic fund UIDB/04469/2020.info:eu-repo/semantics/publishedVersio