Development of a Versatile Lipid Core for Nanostructured Lipid Carriers (NLCs) Using Design of Experiments (DoE) and Raman Mapping

The objective of this study was to develop a versatile lipid core for the 'brick-dust type of drugs' (poorly water-soluble and poorly lipid-soluble drugs). In the first step, excipients of different polarities were classified according to their behavior in aqueous solutions. Subsequently, binary mixtures were prepared with cetyl palmitate (Crodamol™ CP pharma, Campinas, São Paulo, Brazil) as the solid lipid, and its miscibility with other excipients was evaluated using Raman mapping and classical least squares (CLS). Based on the results, the excipients Crodamol™ CP pharma (hydrophobic), Super Refined™ DMI (dimethyl isosorbide; hydrophilic, Mill Hall, PA, USA), and Super Refined™ Lauryl Lactate (lauryl lactate, medium polarity, Mill Hall, PA, USA) were chosen to compose the lipid core. The ideal proportion of these excipients was determined using a mixture design and the standard deviation (STD) of image histograms as the response variables. After statistical evaluation of the DoE results, the final composition was determined, and drugs with different logP (0 to 10) and physicochemical characteristics were evaluated in the optimized mixture. The drugs butamben (Sigma-Aldrich Co., Spruce Street, St. Louis, MO, USA), tacrolimus (NutriFarm, São Paulo, Brazil), atorvastatin calcium, and resveratrol (Botica da Terra, Campinas, Brazil) presented a homogeneous distribution in the optimized lipid core, indicating that this is a promising system to be used in nanostructured lipid carrier (NLC) formulations of such types of drugs.

Development of an ultra-high-performance supercritical fluid chromatography method for the analysis of phenols in the pyrolysis aqueous fraction

The pyrolysis process consists of the thermal decomposition of biomass in an inert atmosphere, which produces a liquid (bio-oil) composed of a complex mixture of organic compounds, including an oil and water phase. The aqueous fraction can reach up to 45% w/w, and understanding its composition is of utmost importance in determining its intended destination, whether for the reuse of compounds in industrial applications or for treating the effluent for disposal. In this study, a fast, direct, and efficient method using ultra-high-performance supercritical fluid chromatography (UHPSFC) was developed and optimized for monitoring phenols in aqueous samples obtained from the pyrolysis processing of six different biomass sources. The following parameters were evaluated for method optimization: stationary phase type, mobile phase flow, organic modifier, sample diluent, temperature, pressure, and modifier gradient time. With a total analysis time of 26 min, out of the fourteen (14) investigated phenolic compounds, eleven (11) were successfully separated after method optimization, and among them, five (5) were quantified in all six aqueous fractions. The aqueous fractions of residue from cowpea pod (1.89 mg.mL-1), sugar apple (3.09 mg.mL-1), and acerola (4.79 mg.mL-1) presented lower concentrations compared to grape (8.16 mg.mL-1), pine nuts (6.68 mg.mL-1), and guava (6.05 mg.mL-1) fractions. However, even at lower concentrations, all biomasses showed promising results regarding the phenolic compound content, analytes that have high added value for the chemical industry.

Improved Local Anesthesia at Inflamed Tissue Using the Association of Articaine and Copaiba Oil in Avocado Butter Nanostructured Lipid Carriers

Unsuccessful anesthesia often occurs under an inflammatory tissue environment, making dentistry treatment extremely painful and challenging. Articaine (ATC) is a local anesthetic used at high (4%) concentrations. Since nanopharmaceutical formulations may improve the pharmacokinetics and pharmacodynamics of drugs, we encapsulated ATC in nanostructured lipid carriers (NLCs) aiming to increase the anesthetic effect on the inflamed tissue. Moreover, the lipid nanoparticles were prepared with natural lipids (copaiba (Copaifera langsdorffii) oil and avocado (Persia gratissima) butter) that added functional activity to the nanosystem. NLC-CO-A particles (~217 nm) showed an amorphous lipid core structure according to DSC and XDR. In an inflammatory pain model induced by λ-carrageenan in rats, NLC-CO-A improved (30%) the anesthetic efficacy and prolonged anesthesia (3 h) in relation to free ATC. In a PGE2-induced pain model, the natural lipid formulation significantly reduced (~20%) the mechanical pain when compared to synthetic lipid NLC. Opioid receptors were involved in the detected analgesia effect since their blockage resulted in pain restoration. The pharmacokinetic evaluation of the inflamed tissue showed that NLC-CO-A decreased tissue ATC elimination rate (ke) by half and doubled ATC’s half-life. These results present NLC-CO-A as an innovative system to break the impasse of anesthesia failure in inflamed tissue by preventing ATC accelerated systemic removal by the inflammatory process and improving anesthesia by its association with copaiba oil.

Metabolite Profiling of Soy By-Products: A Comprehensive Approach

Soy is the major oilseed crop as soybeans are widely used to produce biofuel, food, and feed. Other parts of the plant are left on the ground after harvest. The accumulation of such by-products on the soil can cause environmental problems. This work presents for the first time a comprehensive metabolite profiling of soy by-products collected directly from the ground just after mechanical harvesting. A two-liquid-phase extraction using n-heptane and EtOH-H2O 7:3 (v/v) provided extracts with complete characterization by gas chromatography and ultra-high-performance liquid chromatography both coupled to time-of-flight mass spectrometry. A total of 146 metabolites, including flavones, flavonols, isoflavonoids, fatty acids, steroids, mono-, sesqui-, di-, and triterpenoids, were tentatively identified in soy by-products and soybeans. These proved to be sources of a wide range of bioactive metabolites, thus suggesting that they could be valorized while reducing potential environmental damage in line with a circular economy model.

Nanocarriers From Natural Lipids With In Vitro Activity Against Campylobacter jejuni

Campylobacter jejuni (CJ) is the most prevalent zoonotic pathogen of chicken meat and related products, which may lead to gastroenteritis and autoimmune diseases in humans. Although controlling this bacterium is important, CJ strains resistance against traditional antibiotic therapy has been increased. Vegetable oils and fats are natural biomaterials explored since the Ancient times, due to their therapeutic properties. Nanotechnology has promoted the miniaturization of materials, improving bioavailability and efficacy, while reducing the toxicity of loaded active molecules. In this work, a screening of 28 vegetable oils was firstly performed, in order to select anti-CJ candidates by the disc diffusion test. Thus, the selected liquid lipids were used as active molecules in nanostructured lipid carriers (NLC) formulations. The three resultant systems were characterized in terms of particle size (~200 nm), polydispersity index (~0.15), and zeta potential (~-35mV), and its physicochemical stability was confirmed for a year, at 25°C. The structural properties of NLC were assessed by infrared (FTIR-ATR) and differential scanning calorimetry (DSC) analyses. The spherical nanoparticle morphology and narrow size distribution was observed by transmission electron microscopy (TEM) and field emission scanning electron (FE-SEM) analyses, respectively. Then, the in vitro antimicrobial activity test determined the minimum inhibitory concentration (MIC) of each formulation against CJ strains, in both free (1-3 mg/ml^-1) and sessile (0.78 mg/ml^-1) forms. Finally, the in vitro biocompatibility of NLC was demonstrated through cell viability using VERO cell line, in which F6 was found twice less cytotoxic than pure olibanum oil. Considering the abovementioned achieved, F6 formulation is able to be evaluated in the in vivo anti-CJ efficacy assays.

Multiblock modelling on the study of the kinetic degradation of rosuvastatin calcium in the presence of retention time shifts and rank deficiency

In pharmaceutical development, forced degradation studies are mandatory before the commercialization of any drug product. They aim at identifying the possible degradation routes and the potential products that may be formed during drug product shelf life. The most widely used techniques for monitoring this in the pharmaceutical industry are hyphenated techniques such as Liquid Chromatography coupled to ultraviolet diode array detector (LC-DAD). There are however some drawbacks, such as long analysis times required for the elution of all compounds and coelution, which is not easily detected since degradation products usually have spectra very similar to that of the drug. Chemometrics methods applied to LC-DAD data are capable of solving this issue, but the approaches described in the literature first require peak alignment to solve the rank deficiency problem, which is a delicate preprocessing method for high order data. The present work describes another approach where extra information - the kinetic degradation profiles - is included for the modelling, generating a third-order data set for each sample, resulting in a four-way array (sample x retention times x spectra x degradation profile). This approach has the advantage of using the information in the third mode to solve the peak co-elution problem without the need for peak alignment among samples. With the proposed approach, it was possible to study the degradation of calcium rosuvastatin, a modern cholesterol lowering drug, using a 2 min-run, despite all the challenges in the modelling of this data. The proposed strategy was compared to an approach based on augmenting the matrix in the spectral/kinetic modes (second order modelling strategy).

Characterization of the lipid profile from coconut (Cocos nucifera L.) oil of different varieties by electrospray ionization mass spectrometry associated with principal component analysis and independent component analysis

Coconut oil (CO) from fifteen different varieties of coconuts (Cocos nucifera L.) and one CO processed on an industrial scale were analyzed by electrospray ionization mass spectrometry (ESI-MS) and the data processed using the chemometric tools principal component analysis and independent component analysis. ESI-MS fingerprinting of lipid compounds showed predominance of diacylglycerols and triacylglycerols, as confirmed by high-resolution MS measurements. Chemometric processing of the ESI-MS data differentiated the coconut oil samples, showing that different coconut varieties/cultivars produce oils with distinguishable abundances of lipidic compounds. Thus ESI-MS analysis followed by data treatment using chemometric tools offers a tool able to classify the industrial coconut oils in a fast, simple and effective way, as well as serving as a potential method to identify the coconut varieties by the CO origin, and the occurrence of any adulteration. The procedure may also be applied for quality control of the industrial processes.

Nanohybrid hydrogels designed for transbuccal anesthesia

BACKGROUND

Local anesthesia in dentistry is by far the most terrifying procedure for patients, causing treatment interruption. None of the commercially available topical formulations is effective in eliminating the pain and phobia associated to the needle insertion and injection.

MATERIALS AND METHODS

In this work we prepared a nanostructured lipid-biopolymer hydrogel for the sustained delivery of lidocaine-prilocaine (LDC-PLC) for transbuccal pre-anesthesia. The lipid was composed of optimized nanostructured lipid carriers (NLC) loaded with 5% LDC-PLC (NLC/LDC-PLC). The biopolymer counterpart was selected among alginate, xanthan (XAN), and chitosan matrices. The XAN-NLC hydrogel presented the most uniform aspect and pseudoplastic rheological profile, as required for topical use; therefore, it was selected for subsequent analyses. Accelerated stability tests under critical conditions (40°C; 75% relative humidity) were conducted for 6 months, in terms of drug content (mg/g), weight loss (%), and pH.

RESULTS

In vitro LDC-PLC release profile through Franz diffusion cells revealed a bimodal kinetics with a burst effect followed by the sustained release of both anesthetics, for 24 hours. Structural analyses (fourier transform infrared spectroscopy, differential scanning calorimetry and scanning electron microscopy) gave details on the molecular organization of the hybrid hydrogel, confirming the synergic interaction between the components. Safety and efficacy were evaluated through in vitro cell viability (3T3, HaCat, and VERO cells) and in vivo antinociceptive (tail-flick, in mice) tests, respectively. In comparison to a control hydrogel and the eutectic mixture of 5% LDC-PLC cream (EMLA®), the XAN-NLC/LDC-PLC hybrid hydrogel doubled and quadrupled the anesthetic effect (8 hours), respectively.

CONCLUSION

Considering such exciting results, this multifaceted nanohybrid system is now ready to be further tested in clinical trials.

Study of the chromatographic parameters of ultra-high-performance supercritical fluid chromatography and method development using a design of experiments approach for the quantification of pesticides in lettuce

We examine the potential of ultra-high-performance supercritical fluid chromatography for multiresidue quantification of ten pesticides commonly applied to lettuce and compares it to ultra-high-performance liquid chromatography. Initially, a thorough study of the stationary and mobile phase composition and injection solvent was carried out. In a second step, a chemometric approach based on design of experiments was used to simultaneously study the influence of temperature, pressure, and percentage of ethanol on the retention, resolution and symmetry of the peaks. Using this approach, it was possible to obtain the Design Space, a robust region where complete separation of the analytes was achieved, with acceptable peak shape. Both methods were validated according to the figures of merit: selectivity, linearity, quantification limit, accuracy (in terms of recovery), and precision (repeatability and intermediate precision) and used to quantify the pesticides in lettuce samples. Comparing both techniques, it was concluded that the limits of quantification, accuracy, and precision were similar. However, in supercritical fluid chromatography, a reduced volume of organic solvent was used, the method was faster and generated lower amounts of residues.

Revisiting quick, easy, cheap, effective, rugged, and safe parameters for sample preparation in pesticide residue analysis of lettuce by liquid chromatography-tandem mass spectrometry

A new analytical method using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure for multi-residue determination of 16 multiclass pesticides in five different types of lettuce was developed using high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry. The QuEChERS procedure was optimized in terms of extractor solvent, partitioning salts and clean-up salts, through recovery, gravimetric analysis and matrix-effect studies. Microwave extraction and the use of disposable pipette extraction in the clean-up step were also tested, providing interesting alternatives to the traditional QuEChERS method, depending on the pesticides properties. The use of a laboratory-made phenyl-type sorbent, based on silica and poly(2-phenylpropyl)methylsiloxane, was studied in the clean-up step, presenting promising results as a substitute for primary secondary amine (PSA). The optimized QuEChERS method was defined employing acetonitrile, citrate buffer and clean-up with PSA, MgSO4 and graphitized carbon black. The method developed was validated according to Document SANTE/11945/2015 and proved to be selective, accurate and precise, obtaining limits of quantification from 5μgkg-1 and recoveries in the range of 70-120% with relative standard deviation≤20%. The method was applied on 14 real samples from commercial markets in Brazil and 21% of the samples analyzed presented irregularities, according to local pesticides regulations.

Raman imaging spectroscopic characterization of modified poly(dimethylsiloxane) for micro total analysis systems applications

Methacryloxypropyl-modified poly(dimethylsiloxane) rubbers were obtained from poly(dimethylsiloxane), PDMS, and methacryloxypropyltrimethoxysilane, MPTMS, by polycondensation reactions. The modified rubbers, prepared with 20 and 30% (v/v) of MPTMS, were used as substrates for microchannel fabrication by the CO(2) laser ablation technique. Raman imaging spectroscopy was used for the surface characterization, showing the homogeneity of the rubbery material, with uniform distribution of the crosslinking centers. Under the experimental conditions used, damage to the rubber from the CO(2) laser radiation used for the channel engraving was not observed. Correlation maps of the surface were obtained in order to spatially evaluate the modification inside and outside the channels. The correlations between the methacryloxypropyl-modified poly(dimethylsiloxane) rubbers and MPTMS (spectral range of 1800-1550 cm(-1)) and PDMS (spectral range of 820-670 cm(-1)) precursors were higher than 0.95 and 0.99, respectively. In addition, Raman imaging spectroscopy allows monitoring the topography of the fabricated microchannel.