Encapsulation of eucalyptus and Litsea cubeba essential oils using zein nanopolymer: Preparation, characterization, storage stability, and antifungal evaluation.

The encapsulation of essential oils (EOs) in protein-based biopolymeric matrices stabilized with surfactant ensures protection and physical stability of the EO against unfavorable environmental conditions. Accordingly, this study prepared zein nanoparticles loaded with eucalyptus essential oil (Z-EEO) and Litsea cubeba essential oil (Z-LEO), stable and with antifungal activity against Colletotrichum lindemuthianum, responsible for substantial damage to bean crops. The nanoparticles were prepared by nanoprecipitation with the aid of ultrasound treatment and characterized. The nanoparticles exhibited a hydrodynamic diameter close to 200 nm and PDI < 0.3 for 120 days, demonstrating the physical stability of the carrier system. Scanning electron microscopy and Transmission electron microscopy revealed that the nanoparticles were smooth and uniformly distributed spheres. Fourier-transform infrared spectroscopy showed interaction between zein and EOs through hydrogen bonding and hydrophobic interactions. Thermogravimetric analysis demonstrated the thermal stability of the nanoparticles compared to pure bioactive compounds. The nanoparticles exhibited a dose-dependent effect in inhibiting the fungus in in vitro testing, with Z-EEO standing out by inhibiting 70.0 % of the mycelial growth of C. lindemuthianum. Therefore, the results showed that zein has great potential to encapsulate hydrophobic compounds, improving the applicability of the bioactive compound as a biofungicide, providing protection for the EO.

Impact of ultrasound process on cassava starch nanoparticles and Pickering emulsions stability.

Using green techniques to convert native starches into nanoparticles is an interesting approach to producing stabilizers for Pickering emulsions, aiming at highly stable emulsions in clean label products. Nanoprecipitation was used to prepare the Pickering starch nanoparticles, while ultrasound technique has been used to modulate the size of these nanoparticles at the same time as the emulsion was developed. Thus, the main objective of this study was to evaluate the stabilizing effect of cassava starch nanoparticles (SNP) produced by the nanoprecipitation technique combined with ultrasound treatment carried out in the presence of water and oil (more hydrophobic physicochemical environment), different from previous studies that carry out the mechanical treatment only in the presence of water. The results showed that the increased ultrasound energy input could reduce particle size (117.58 to 55.75 nm) and polydispersity (0.958 to 0.547) in aqueous dispersions. Subsequently, Pickering emulsions stabilized by SNPs showed that increasing emulsification (ultrasonication) time led to smaller droplet sizes and monomodal size distribution. Despite flocculation, long-term ultrasonication (6 and 9 min) caused little variation in the droplet size after 7 days of storage. The cavitation effects favored the interaction between oil droplets through weak attraction forces and particle sharing, favoring the Pickering stabilization against droplet coalescence. Our results show the potential to use only physical modifications to obtain nanoparticles that can produce coalescence-stable emulsions that are environmentally friendly.

PLGA-LEC/F127 hybrid nanoparticles loaded with curcumin and their modulatory effect on monocytes.

Aim: To investigate the effect of surfactant type on curcumin-loaded (CUR) PLGA nanoparticles (NPs) to modulate monocyte functions. Materials & methods: The nanoprecipitation method was used, and PLGA NPs were designed using Pluronic F127 (F127) and/or lecithin (LEC) as surfactants. Results: The Z-average of the NPs was <200 nm, they had a spherical shape, Derjaguin-Muller-Toporov modulus >0.128 MPa, they were stable during storage at 4°C, ζ-potential ∼-40 mV, polydispersity index <0.26 and % EE of CUR >94%. PLGA-LEC/F127 NPs showed favorable physicochemical and nanomechanical properties. These NPs were bound and internalized mainly by monocytes, suppressed monocyte-induced reactive oxygen species production, and decreased the ability of monocytes to modulate T-cell proliferation. Conclusion: These results demonstrate the potential of these NPs for targeted therapy.

This study explores how different surfactants affect curcumin-loaded PLGA nanoparticles, a biodegradable polymer. The nanoparticles were designed using Pluronic F127 and/or lecithin as surfactants. They are less than 200 nm and spherical. They are stable when stored at 4 °C, with a surface charge of about -40 mV, and can encapsulate more than 94% of curcumin.The results of this study are promising, showing that PLGA nanoparticles using a mixture of lecithin and Pluronic F127 as surfactants have favorable properties toward monocyte adhesion. They are primarily taken up by monocytes, a type of white blood cell, and demonstrate a remarkable ability to reduce the production of reactive oxygen species, which can cause cell damage, as well as the ability of monocytes to stimulate the proliferation of T cells. This underscores the potential of these nanoparticles in targeted therapy, particularly in diseases where monocytes play a pivotal role, such as chronic inflammatory conditions.

In situ extraction/encapsulation of olive leaves antioxidants in zein for improved oxidative stability of edible oils.

This study presents a sustainable and cost-effective method for preserving the bioactivity of phenolic compounds in olive leaves (OLE) during their application. The extraction and nanoencapsulation of OLE were performed in a single-step process using a rotor-stator system with zein as the encapsulating agent. The nanoprecipitation step was carried out using an aqueous sodium caseinate solution, resulting in spherical particles with an average diameter of about 640 nm, as confirmed by Transmission Electron Microscopy. Thermal characterization showed that the produced nanoparticles were more thermally stable than free OLE until 250 °C, and FTIR spectra indicated effective interaction between the phenolic compounds and zein. Antioxidant activity was evaluated using TBARS, DPPH, ABTS, and FRAP assays, with results showing that encapsulated OLE had lower antioxidant activity than free OLE. The best antioxidant capacity results were determined by TBARS assay, with IC50 results equal to 43 and 103 µgOLE/mL for free and encapsulated OLE, respectively. No anti-inflammatory potential was detected for both samples using the RAW 264.7 model, and only free OLE showed cytotoxic activity against lung cancer and gastric carcinoma. Encapsulated and free OLE were used as antioxidants in soy, palm, and palm kernel oils and compared to BHT using Rancimat. The Schaal Oven Test was also performed, and the PARAFAC chemometric method analyzed the UV-Vis spectra, which revealed high stability of the oil when 300 mg or the nanoparticles were added per kg oil. Results suggested that zein-encapsulated olive leaf antioxidants can improve the oxidative stability of edible oils.

PEG 400:Trehalose Coating Enhances Curcumin-Loaded PLGA Nanoparticle Internalization in Neuronal Cells.

This work proposes a combination of polyethylene glycol 400 (PEG) and trehalose as a surface modification approach to enhance PLGA-based nanoparticles as a drug carrier for neurons. PEG improves nanoparticles' hydrophilicity, and trehalose enhances the nanoparticle's cellular internalization by inducing a more auspicious microenvironment based on inhibiting cell surface receptor denaturation. To optimize the nanoprecipitation process, a central composite design was performed; nanoparticles were adsorbed with PEG and trehalose. PLGA nanoparticles with diameters smaller than 200 nm were produced, and the coating process did not considerably increase their size. Nanoparticles entrapped curcumin, and their release profile was determined. The nanoparticles presented a curcumin entrapment efficiency of over 40%, and coated nanoparticles reached 60% of curcumin release in two weeks. MTT tests and curcumin fluorescence, with confocal imaging, were used to assess nanoparticle cytotoxicity and cell internalization in SH-SY5Y cells. Free curcumin 80 µM depleted the cell survival to 13% at 72 h. Contrariwise, PEG:Trehalose-coated curcumin-loaded and non-loaded nanoparticles preserved cell survival at 76% and 79% under the same conditions, respectively. Cells incubated with 100 µM curcumin or curcumin nanoparticles for 1 h exhibited 13.4% and 14.84% of curcumin's fluorescence, respectively. Moreover, cells exposed to 100 µM curcumin in PEG:Trehalose-coated nanoparticles for 1 h presented 28% fluorescence. In conclusion, PEG:Trehalose-adsorbed nanoparticles smaller than 200 nm exhibited suitable neural cytotoxicity and increased cell internalization proficiency.

The mechanism, biopolymers and active compounds for the production of nanoparticles by anti-solvent precipitation: A review.

The anti-solvent precipitation method has been investigated to produce biopolymeric nanoparticles in recent years. Biopolymeric nanoparticles have better water solubility and stability when compared with unmodified biopolymers. This review article focuses on the analysis of the state of the art available in the last ten years about the production mechanism and biopolymer type, as well as the used of these nanomaterials to encapsulate biological compounds, and the potential applications of biopolymeric nanoparticles in food sector. The revised literature revealed the importance to understand the anti-solvent precipitation mechanism since biopolymer and solvent types, as well as anti-solvent and surfactants used, can alter the biopolymeric nanoparticles properties. In general, these nanoparticles have been produced using polysaccharides and proteins as biopolymers, especially starch, chitosan and zein. Finally, it was identified that those biopolymers produced by anti-solvent precipitation were used to stabilize essential oils, plant extracts, pigments, and nutraceutical compounds, promoting their application in functional foods.

Zein nanoparticles for drug delivery: Preparation methods and biological applications.

Zein, a vegetable protein extracted from corn (Zea mays L.), forms a gastro-resistant and mucoadhesive polymer that is cheap and easy to obtain and facilitates the encapsulation of bioactives with hydrophilic, hydrophobic, and amphiphilic properties. The methods used for synthesizing these nanoparticles include antisolvent precipitation/nanoprecipitation, pH-driven, electrospraying, and solvent emulsification-evaporation methods. Each method has its advantages in the preparation of nanocarriers, nevertheless, all of them enable the production of zein nanoparticles that are stable and resistant to environmental factors, with different biological activities required in the cosmetic, food, and pharmaceutical industries. Therefore, zein nanoparticles are promising nanocarriers that can encapsulate various bioactives with anti-inflammatory, antioxidant, antimicrobial, anticancer, and antidiabetic properties. This article reviews the principal methods for obtaining zein nanoparticles containing bioactives, the advantages and characteristics of each method, as well as the main biological applications of nanotechnology-based formulations.

Tuning the morphology of block copolymer-based pH-triggered nanoplatforms as driven by changes in molecular weight and protocol of manufacturing.

The ability to tune size and morphology of self-assemblies is particularly relevant in the development of delivery systems. By tailoring such structural parameters, one can provide larger cargo spaces or produce nanocarriers that can be loaded by hydrophilic and hydrophobic molecules starting ideally from the same polymer building unit. We herein demonstrate that the morphology of block copolymer-based pH-triggered nanoplatforms produced from poly(2-methyl-2-oxazoline)m-b-poly[2-(diisopropylamino)-ethyl methacrylate]n (PMeOxm-b-PDPAn) is remarkably influenced by the overall molecular weight of the block copolymer, and by the selected method used to produce the self-assemblies. Polymeric vesicles were produced by nanoprecipitation using a block copolymer of relatively low molecular weight (Mn âˆ¼ 10 kg.mol-1). Very exciting though, despite the high hydrophobic weight ratio (wPDPA > 0.70), this method conducted to the formation of core-shell nanoparticles when block copolymers of higher molecular weight were used, thus suggesting that the fast (few seconds) self-assembly procedure is controlled by kinetics rather than thermodynamics. We further demonstrated the formation of vesicular structures using longer chains via the solvent-switch approach when the "switching" to the bad solvent is performed in a time scale of a few hours (approximately 3 hs). We accordingly demonstrate that using fairly simple methods one can easily tailor the morphology of such block copolymer self-assemblies, thereby producing a variety of structurally different pH-triggered nanoplatforms via a kinetic or thermodynamically-controlled process. This is certainly attractive towards the development of nanotechnology-based cargo delivery systems.

Synthesis of Organic Semiconductor Nanoparticles with Different Conformations Using the Nanoprecipitation Method.

In recent years, nanoparticulate materials have aroused interest in the field of organic electronics due to their high versatility which increases the efficiency of devices. In this work, four different stable conformations based on the organic semiconductors P3HT and PC71BM were synthesized using the nanoprecipitation method, including blend and core-shell nanoparticles. All nanoparticles were obtained free of surfactants and in aqueous suspensions following the line of ecologically correct routes. The structural and optoelectronic properties of the nanoparticles were investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV-visible absorption spectroscopy and UV-visible photoluminescence (PL). Even in aqueous media, the blend and core-shell nanoparticles exhibited a greater light absorption capacity, and these conformations proved to be effective in the process of dissociation of excitons that occurs at the P3HT donor/PC71BM acceptor interface. With all these characteristics and allied to the fact that the nanoparticles are surfactant-free aqueous suspensions, this work paves the way for the use of these colloids as a photoactive layer of organic photovoltaic devices that interface with biological systems.

Generation of curcumin-loaded albumin nanoparticles by using off-the-shelf microfluidics driven by gravity.

The generation albumin-based nanocarriers by precipitation from solution has great interest in the formulation of advanced nutritional products. Microfluidic techniques enable the implementation of low energy and continuum processes, with fast mass transfer and homogeneous mixing at the microscale. Here we describe the microfluidic generation of curcumin-loaded alpha lactalbumin nanoparticles in a simple and inexpensive way, by using off-the-shelf devices designed to produce solvent-shifting nanoprecipitation in core-sheath flows driven by gravity, which has not been reported before. Nanoparticles were characterized by dynamic light scattering, electron microscopy, and infrared spectroscopy. The microfluidic operating conditions were defined by theory and experiments, and the critical parameters controlling the nanoparticles diameter were identified. The prepared nanoparticles resulted practically monodisperse, the curcumin entrapment efficiency was about 40 %, and almost 70 % of the bioactive was gradually delivered in release experiments. The proposed methodology is a promising route to scale up the microfluidic elaboration of nanoparticles for the entrapment of active ingredients.

Production of methylcellulose films functionalized with poly-ε-caprolactone nanocapsules entrapped ß-carotene for food packaging application.

Nowadays, there is a worldwide demand in the production of innovative packaging that release active compounds to increase the shelf life of perishable food products. Therefore, this study produced methylcellulose films functionalized with poly-ε-caprolactone nanocapsules entrapped ß-carotene. The nanoparticles were produced by the nanoprecipitation method, and 10, 30, and 50 % of nanoparticles colloidal solution was added in the methylcellulose filmogenic solution. The films were characterized by the mechanical, physicochemical properties, antioxidant activity, and release of ß-carotene from the polymeric matrix to a food simulant. The results demonstrated satisfactory mechanical properties; however, the addition of nanoparticles decreased the Young's Modulus and increased the elongation at break. Regarding light transmission, the incorporation of ß-carotene nanoparticles promoted a decrease in the percentage of ultraviolet ray's transmittance through the film matrix, as well as visible light. The incorporation of nanoparticles improved the antioxidant activity of the films, which was proportional to the concentration of ß-carotene used in the formulation. The release of ß-carotene reached a maximum value of 10.93 µg g-1 film containing 70 % nanoparticles, which was a desired profile for food application. Finally, the methylcellulose films functionalized with poly-ε-caprolactone nanocapsules can release ß-carotene, and therefore, can be considered as a novel nanomaterial for food conservation, with a potential to increase the shelf life of perishable food products.

In Vitro Validation of Antiparasitic Activity of PLA-Nanoparticles of Sodium Diethyldithiocarbamate against Trypanosoma cruzi.

Trypanosoma cruzi is a protozoan parasite responsible for Chagas disease, which affects millions around the world and is not treatable in its chronic stage. Sodium diethyldithiocarbamate is a compound belonging to the carbamate class and, in a previous study, demonstrated high efficacy against T. cruzi, showing itself to be a promising compound for the treatment of Chagas disease. This study investigates the encapsulation of sodium diethyldithiocarbamate by poly-lactic acid in nanoparticles, a system of biodegradable nanoparticles that is capable of reducing the toxicity caused by free DETC against cells and maintaining the antiparasitic activity. The nanosystem PLA-DETC was fabricated using nanoprecipitation, and its physical characterization was measured via DLS, SEM, and AFM, demonstrating a small size around 168 nm and a zeta potential of around -19 mv. Furthermore, the toxicity was determined by MTT reduction against three cell lines (VERO, 3T3, and RAW), and when compared to free DETC, we observed a reduction in cell mortality, demonstrating the importance of DETC nanoencapsulation. In addition, the nanoparticles were stained with FITC and put in contact with cells for 24 h, followed by confirmation of whether the nanosystem was inside the cells. Lastly, the antiparasitic activity against different strains of T. cruzi in trypomastigote forms was determined by resazurin reduction and ROS production, which demonstrated high efficacy towards T. cruzi equal to that of free DETC.

Nanoprecipitation technology to prepare carrier systems of interest in pharmaceutics: An overview of patenting.

Nanoprecipitation is a practical method to prepare carriers at the nanometric scale, which attracts attention in pharmaceutics because of its low cost, easy setup, the versatility of the starting materials, possibility to obtain different kinds of carriers, and minimal environmental impact. Since 1986, this technique has been extensively employed in research; therefore, this paper focuses on state of art regarding inventions wherein it is employed. To this end, 133 nanoprecipitation-based patent families are identified in the PatSnap® platform, which allows identifying general trends. Afterwards, a sample of 40 patent families reported as granted (21 families) or patent applications (19 families) during the last decade are studied in depth to establish the research tendencies. Undoubtedly, Chinese universities are positioned as leaders in this field, and cancer treatments are the more claimed use followed far behind for developments targeting neurodegenerative and diabetes diseases. New proposals on targeted and stimuli response particles are also claimed, and development of polymers, prodrugs, and improvements to the technique such as the flash-nanoprecipitation, use of microfluidics, or design of green process are relevant. Interestingly, nanoprecipitation-related patent families have significantly increased during the last decade, being the 71% of the total, which makes alluring the perspectives about its industrial harnessing.

Poly-ε-caprolactone Nanoparticles Loaded with 4-Nerolidylcatechol (4-NC) for Growth Inhibition of Microsporum canis.

Dermatophyte fungal infections are difficult to treat because they need long-term treatments. 4-Nerolidylcatechol (4-NC) is a compound found in Piper umbellatum that has been reported to demonstrate significant antifungal activity, but is easily oxidizable. Due to this characteristic, the incorporation in nanostructured systems represents a strategy to guarantee the compound's stability compared to the isolated form and the possibility of improving antifungal activity. The objective of this study was to incorporate 4-NC into polymeric nanoparticles to evaluate, in vitro and in vivo, the growth inhibition of Microsporum canis. 4-NC was isolated from fresh leaves of P. umbellatum, and polymer nanoparticles of polycaprolactone were developed by nanoprecipitation using a 1:5 weight ratio (drug:polymer). Nanoparticles exhibited excellent encapsulation efficiency, and the antifungal activity was observed in nanoparticles with 4-NC incorporated. Polymeric nanoparticles can be a strategy employed for decreased cytotoxicity, increasing the stability and solubility of substances, as well as improving the efficacy of 4-NC.

Optimization and Characterization of Protein Nanoparticles for the Targeted and Smart Delivery of Cytochrome c to Non-Small Cell Lung Carcinoma.

The delivery of Cytochrome c (Cyt c) to the cytosol stimulates apoptosis in cells where its release from mitochondria and apoptotic induction is inhibited. We developed a drug delivery system consisting of Cyt c nanoparticles decorated with folate-poly(ethylene glycol)-poly(lactic-co-glycolic acid)-thiol (FA-PEG-PLGA-SH) to deliver Cyt c into cancer cells and tested their targeting in the Lewis Lung Carcinoma (LLC) mouse model. Cyt c-PLGA-PEG-FA nanoparticles (NPs) of 253 ± 55 and 354 ± 11 nm were obtained by Cyt c nanoprecipitation, followed by surface decoration with the co-polymer SH-PLGA-PEG-FA. The internalization of Cyt c-PLGA-PEG-FA nanoparticles (NPs) in LLC cells was confirmed by confocal microscopy. NP caspase activation was more efficient than the NP-free formulation. Caspase activity assays showed NPs retained 88-96% Cyt c activity. The NP formulations were more effective in decreasing LLC cell viability than NP-free formulation, with IC50 49.2 to 70.1 µg/mL versus 129.5 µg/mL, respectively. Our NP system proved to be thrice as selective towards cancerous than normal cells. In vivo studies using near infrared-tagged nanoparticles show accumulation in mouse LLC tumor 5 min post-injection. In conclusion, our NP delivery system for Cyt c shows superiority over the NP-free formulation and reaches a folic acid-overexpressing tumor in an immune-competent animal model.

Poly-ε-caprolactone Nanoparticles Loaded with 4-Nerolidylcatechol (4-NC) for Growth Inhibition of Microsporum canis

Dermatophyte fungal infections are difficult to treat because they need long-term treatments. 4-Nerolidylcatechol (4-NC) is a compound found in Piper umbellatum that has been reported to demonstrate significant antifungal activity, but is easily oxidizable. Due to this characteristic, the incorporation in nanostructured systems represents a strategy to guarantee the compound's stability compared to the isolated form and the possibility of improving antifungal activity. The objective of this study was to incorporate 4-NC into polymeric nanoparticles to evaluate, in vitro and in vivo, the growth inhibition of Microsporum canis. 4-NC was isolated from fresh leaves of P. Umbellatum, and polymer nanoparticles of polycaprolactone were developed by nanoprecipitation using a 1:5 weight ratio (drug:polymer). Nanoparticles exhibited excellent encapsulation efficiency, and the antifungal activity was observed in nanoparticles with 4-NC incorporated. Polymeric nanoparticles can be a strategy employed for decreased cytotoxicity, increasing the stability and solubility of substances, as well as improving the efficacy of 4-NC(AU).

Synthesis of chitosan biocomposites loaded with pyrrole-2-carboxylic acid and assessment of their antifungal activity against Aspergillus niger.

A wide variety of chitosan (CS) biomaterials have been loaded with different antimicrobial agents to improve the activity of CS against phytopathogenic fungi. Recently, the antimicrobial activity of 1H-pyrrole-2-carboxylic acid (PCA) has been reported as a secondary metabolite of Streptomyces griseus, which was identified as the main bioactive compound in the biological control. However, it is sensitive to light and its activity against filamentous fungi has not yet been reported. The aim of the present research work was to evaluate the biological activity of CS-PCA biocomposites for the control of Aspergillus niger. CS-PCA biocomposites were obtained through nanoprecipitation. In vitro antifungal activity was determined by viability assay, spore germination, morphometric analysis of spores and hyphae, and the analysis of cellular components by fluorescence microscopy. CS-PCA showed an average size and Z potential of 502 ± 72 nm and + 54.7 ± 15 mV, respectively. Micrographs demonstrated well-distributed biocomposites with an apparently spherical shape. A new signal at 1473 cm-1 in the FT-IR spectrum of the CS-PCA biocomposite was observed, confirming the presence of PCA in the composition of the CS-PCA nanosystem. CS-PCA biocomposites reduced the spores' viability by up to 58%. Effects on fungi morphometry, observed as an increase in the spores' average diameter, swelling, distortion, and an increase in the branching of hyphae, were observed. Fluorescence analysis showed oxidative stress and membrane and cell wall damage, mainly at early growth stages. The inhibitory effect against CS-resistant fungi, such as A. niger, opens a door for the control of CS-sensitive fungi.

Characterization of Nanospheres Containing Zanthoxylum riedelianum Fruit Essential Oil and Their Insecticidal and Deterrent Activities against Bemisia tabaci (Hemiptera: Aleyrodidae).

The aim of our study was to produce and characterize poly-ε-caprolactone (PCL) nanospheres containing essential oils from Zanthoxylum riedelianum fruit and to evaluate their stability gains as well as their insecticidal and deterrent activities against whitefly (Bemisia tabaci). The PCL nanospheres exhibited a homogeneous spherical morphology, with particle diameters between 106.7 nm and 129.2 nm, pH of approximately 6, zeta potential (ZP) lower than -19.0 mV and encapsulation efficiency higher than 98%. Only 43% of the nanoencapsulated essential oil (NSEO) was degraded in response to ultraviolet light, whereas the essential oil (EO) degraded by 76% over the same period. In a free-choice test, the NSEO and EO reduced the number of whitefly eggs by approximately 70%. NSEO and EO at 1.5% killed 82.87% and 91.23% of 2nd-instar nymphs of whitefly, respectively. Although NSEO displayed lower insecticidal activity, it offers a greater advantage over the free EO, due to protection conferred by polymer against photodegradation. Therefore, its usage may optimize the maintenance of essential oils in the field through photoprotection and controlled release. Our results suggest that the EO of Z. riedelianum fruit can be used for B. tabaci management strategy; nevertheless, the benefits of NSEO require further evaluation at the field level.

Finding key nanoprecipitation variables for achieving uniform polymeric nanoparticles using neurofuzzy logic technology.

Nanoprecipitation is a simple and fast method to produce polymeric nanoparticles (Np); however, most applications require filtration or another separation technique to isolate the nanosuspension from aggregates or polydisperse particle production. In order to avoid variability introduced by these additional steps, we report here a systematic study of the process to yield monomodal and uniform Np production with the nanoprecipitation method. To further identify key variables and their interactions, we used artificial neural networks (ANN) to investigate the multiple variables which influence the process. In this work, a polymethacrylate derivative was used for Np (NpERS) and a database with several formulations and conditions was developed for the ANN model. The resulting ANN model had a high predictability (> 70%) for NpERS characteristics measured (mean size, PDI, zeta potential, and number of particle populations). Moreover, the model identified production variables leading to polymer supersaturation, such as mixing time and turbulence, as key in achieving monomodal and uniform NpERS in one production step. Polymer concentration and type of solvent, modifiers of polymer diffusion and supersaturation, were also shown to control NpERS characteristics. The ANN study allowed the identification of key variables and their interactions and resulted in a predictive model to study the NpERS production by nanoprecipitation. In turn, we have achieved an optimized method to yield uniform NpERS which could pave way for polymeric nanoparticle production methods with potential in biological and drug delivery applications.

Analytical validation of an ultraviolet-visible procedure for determining lutein concentration and application to lutein-loaded nanoparticles.

Lutein is a carotenoid presenting known anti-inflammatory and antioxidant properties. Lutein-rich diets have been associated with neurological improvement as well as reduction of the risk of vision loss due to Age-Related Macular Degeneration (AMD). Micro and nanoencapsulation have demonstrated to be effective techniques in protecting lutein against degradation and also in improving its bioavailability. However, actual lutein concentration inside the capsules and encapsulation efficiency are key parameters that must be precisely known when designing in vitro and in vivo tests. In this work an analytical procedure was validated for the determination of the actual lutein content in zein nanoparticles using ultraviolet-visible spectroscopy. Method validation followed the International Conference on Harmonisation (ICH) guidelines which evaluate linearity, detection limit, quantification limit, accuracy and precision. The validated methodology was applied to characterize lutein-loaded nanoparticles.