Caenorhabditis elegans as an alternative in vivo model to determine oral uptake, nanotoxicity, and efficacy of melatonin-loaded lipid-core nanocapsules on paraquat damage

A facile fluorescence-coupling approach to visualizing leonurine uptake and distribution in living cells and Caenorhabditis elegans

BACKGROUND

Caenorhabditis elegans (C. elegans) has been recognized for being a useful model organism in small-molecule drug screens and drug efficacy investigation. However, there remain bottlenecks in evaluating such processes as drug uptake and distribution due to a lack of appropriate chemical tools.

PURPOSE

This study aims to prepare fluorescence-labeled leonurine as an example to monitor drug uptake and distribution of small molecule in C. elegans and living cells.

METHODS

FITC-conjugated leonurine (leonurine-P) was synthesized and characterized by LC/MS, NMR, UV absorption and fluorescence intensity. Leonurine-P was used to stain C. elegans and various mammalian cell lines. Different concentrations of leonurine were tested in conjunction with a competing parent molecule to determine whether leonurine-P and leonurine shared the same biological targets. Drug distribution was analyzed by imaging. Fluorometry in microplates and flow cytometry were performed for quantitative measurements of drug uptake.

RESULTS

The UV absorption peak of leonurine-P was 490∼495 nm and emission peak was 520 nm. Leonurine-P specifically bound to endogenous protein targets in C. elegans and mammalian cells, which was competitively blocked by leonurine. The highest enrichment levels of leonurine-P were observed around 72 h following exposure in C. elegans. Leonurine-P can be used in a variety of cells to observe drug distribution dynamics. Flow cytometry of stained cells can be facilely carried out to quantitatively detect probe signals.

CONCLUSIONS

The strategy of fluorescein-labeled drugs reported herein allows quantification of drug enrichment and visualization of drug distribution, thus illustrates a convenient approach to study phytodrugs in pharmacological contexts.

Evaluation of the effects of zinc oxide (ZnO NPs) nanoparticles synthesized by green synthesis on Caenorhabditis elegans

In recent years, the rapid development of nanotechnology has caused the products obtained with this technology to be used more daily. Information on the effects of these products, which provide great advantages in every respect, on human health and the environment is insufficient. It has been suggested that these nanoparticles may have toxic effects on living things, mostly in animal experiments and cell cultures. In this paper, the organism Caenorhabditis elegans (C. elegans), which contains a genome and biochemical ways highly similar to humans, is used to understand and reveal the metabolism of Zinc oxide nanoparticles (ZnO NPs) toxicological effects. The toxicological effects of ZnO NPs on C. elegans organisms were investigated and the results were evaluated in terms of environment and human health. C. elegans was exposed to commercial ZnO NPs and green synthesized ZnO NPs from Olea europaea (olive tree, OLE). LC50 values were determined by probit analysis (green synthesized ZnO NP LC5024h = 84.97 mg/L, LC5072h = 33.27 mg/L, commercial ZnO NPs LC5024h = 5.75 mg/L, LC5072h = 1.91 mg/L). When the survival times of C. elegans were evaluated by the Kaplan-Meier method, it was seen that commercial ZnO NPs were more toxic than green synthesized ZnO NPs. In MTT tests, it was clearly seen that commercial ZnO NPs and green synthesized ZnO NPs entered the cell and caused different cytotoxicity. While there was a difference between control and 0.5, 2.5, 5, 10, 25, and 50 mg/L doses in commercial ZnO NP applications, there were significant differences between control and 25, 50 mg/L concentrations in green synthesized ZnO NP applications.

Melatonin: A look at protozoal and helminths

Melatonin is a pleiotropic neurohormone found in different animal, plant, and microorganism species. It is a product resulting from tryptophan metabolism in the pineal gland and is widely known for its ability to synchronize the circadian rhythm to antitumor functions in different types of cancers. The molecular mechanisms responsible for its immunomodulatory, antioxidant and cytoprotective effects involve binding to high-affinity G protein-coupled receptors and interactions with intracellular targets that modulate signal transduction pathways. In vitro and in vivo studies have reported the therapeutic potential of melatonin in different infectious and parasitic diseases. In this review, the protective and pathophysiological roles of melatonin in fighting protozoan and helminth infections and the possible mechanisms involved against these stressors will be discussed.

Nanomaterials as a Potential Target for Infectious Parasitic Agents

Despite the technological advancement in the era of personalized medicine and therapeutics development, infectious parasitic causative agents remain one of the most challenging areas of research and development. The disadvantages of conventional parasitic prevention and control are the emergence of multiple drug resistance as well as the non-specific targeting of intracellular parasites, which results in high dose concentration needs and subsequently intolerable cytotoxicity. Nanotechnology has attracted extensive interest to reduce medication therapy adverse effects including poor bioavailability and drug selectivity. Numerous nanomaterials-based delivery systems have previously been shown in animal models to be effective in the treatment of various parasitic infections. This review discusses a variety of nanomaterials-based antiparasitic procedures and techniques as well as the processes that allow them to be targeted to different parasitic infections. This review focuses on the key prerequisites for creating novel nanotechnology-based carriers as a potential option in parasite management, specifically in the context of human-related pathogenic parasitic agents.

Comprehensive Neurotoxicity of Lead Halide Perovskite Nanocrystals in Nematode Caenorhabditis elegans

To date, all-inorganic lead halide perovskite quantum dots have emerged as promising materials for photonic, optoelectronic devices, and biological applications, especially in solar cells, raising numerous concerns about their biosafety. Most of the studies related to the toxicity of perovskite quantum dots (PeQDs) have focused on the potential risks of hybrid perovskites by using zebrafish or human cells. So far, the neurotoxic effects and fundamental mechanisms of PeQDs remain unknown. Herein, a comprehensive methodology is designed to investigate the neurotoxicity of PeQDs by using Caenorhabditis elegans as a model organism. The results show that the accumulation of PeQDs mainly focuses on the alimentary system and head region. Acute exposure to PeQDs results in a decrease in locomotor behaviors and pharyngeal pumping, whereas chronic exposure to PeQDs causes brood decline and shortens lifespan. In addition, some abnormal issues occur in the uterus during reproduction assays, such as vulva protrusion, impaired eggs left in the vulva, and egg hatching inside the mother. Excessive reactive oxygen species formation is also observed. The neurotoxicity of PeQDs is explained by gene expression. This study provides a complete insight into the neurotoxicity of PeQD and encourages the development of novel nontoxic PeQDs.

Comparative toxicity of coal and coal ash: Assessing biological impacts and potential mechanisms through in vitro and in vivo testing

BACKGROUND

Coal and coal ash present inorganic elements associated with negative impacts on environment and human health. The objective of this study was to compare the toxicity of coal and coal ash from a power plant, assess their inorganic components, and investigate the biological impacts and potential mechanisms through in vitro and in vivo testing.

METHODS

Particle-Induced X-ray Emission method was used to quantify inorganic elements and the toxicity was evaluated in Caenorhabditis elegans and Daphnia magna in acute and chronic procedures. The genotoxic potential was assessed using alkaline and FPG-modified Comet assay in HepG2 cells and mutagenicity was evaluated using Salmonella/microsome assay in TA97a, TA100, and TA102 strains.

RESULTS

Inorganic elements such as aluminum (Al) and chromium (Cr) were detected at higher concentrations in coal ash compared to coal. These elements were found to be associated with increased toxicity of coal ash in both Caenorhabditis elegans and Daphnia magna. Coal and coal ash did not induce gene mutations, but showed genotoxic effects in HepG2 cells, which were increased using the FPG enzyme, indicating DNA oxidative damage.

CONCLUSIONS

The combined findings from bioassays using C. elegans and D. magna support the higher toxicity of coal ash, which can be attributed to its elevated levels of inorganic elements. The genotoxicity observed in HepG2 cells confirms these results. This study highlights the need for continuous monitoring in areas affected by environmental degradation caused by coal power plants. Additionally, the analysis reveals significantly higher concentrations of various inorganic elements in coal ash compared to coal, providing insight into the specific elemental composition contributing to its increased toxicity.

Toxicological assessment of minoxidil: A drug with therapeutic potential besides alopecia

Minoxidil is regularly prescribed for alopecia, and its therapeutic potential has expanded in recent times. However, few studies have been conducted to evaluate its toxicity, and controversial findings regarding its mutagenic activities remain unsolved. This study aimed to access cytotoxic, genotoxic, and mutagenic properties of minoxidil using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay, comet assay, and micronucleus test in mouse fibroblast (L929) cells and its point mutation induction potential in the Salmonella/microsome assay. Furthermore, an in vivo toxicity assessment was conducted in Caenorhabditis elegans. Minoxidil showed cytotoxicity at 2.0 mg/mL in MTT assay. Genotoxicity was observed after 3 h treatment in L929 cells using comet assay. No mutagenic effect was observed in both the micronucleus test and the Salmonella/microsome assay. The lethal dose 50 in C. elegans was determined to be 1.75 mg/mL, and a delay in body development was detected at all concentrations. In conclusion, minoxidil induces DNA damage only in early treatment, implying that this DNA damage may be repairable. This observation corroborates the absence of mutagenic activities observed in L929 cells and Salmonella typhimurium strains. However, the toxicity of minoxidil was evident in both C. elegans and L929 cells, underscoring the need for caution in its use.

Gliadin nanoparticles for oral administration of bioactives: Ex vivo and in vivo investigations

This study aims to provide a thorough characterization of Brij O2-stabilized gliadin nanoparticles to be used for the potential oral administration of various compounds. Different techniques were used in order to evaluate their physico-chemical features and then in vivo studies in rats were performed for the investigation of their biodistribution and gastrointestinal transit profiles. The results showed that the gliadin nanoparticles accumulated in the mucus layer of the bowel mucosa and evidenced their ability to move along the digestive systems of the animals. The incubation of the nanosystems with Caenorhabditis elegans, used as an additional in vivo model, confirmed the intake of the particles and evidenced their presence along the entire gastrointestinal tract of these nematodes. The gliadin nanoparticles influenced neither the egg-laying activity of the worms nor their metabolism of lipids up to 10 μg/mL of nanoformulation. The systems decreased the content of the age-related lipofuscin pigment in the nematodes in a dose-dependent manner, demonstrating a certain antioxidant activity. Lastly, dihydroethidium staining showed the absence of oxidative stress upon incubation of the worms together with the formulations, confirming their safe profile. This data paves the way for the future application of the proposed nanosystems regarding the oral delivery of various bioactives.

Melatonin ameliorates acute lung injury caused by paraquat poisoning by promoting PINK1 and BNIP3 expression

Paraquat (PQ) poisoning can result in multiple organ dysfunction syndrome, mainly manifesting as acute lung injury and acute respiratory distress syndrome. No specific cure exists for PQ poisoning. However, by scavenging mitochondrial DNA (mtDNA), the damage-associated molecular pattern during PQ poisoning, mitophagy can ameliorate the downstream inflammatory pathways activated by mtDNA. Melatonin (MEL), however, can promote the expression of PINK1 and BNIP3, which are key proteins involved in mitophagy. In this study, we first explored whether MT could reduce PQ-induced acute lung injury by affecting mitophagy in animal models, and then, we studied the specific mechanism associated with this process through in vitro experiments. We also evaluated MEL intervention in the PQ group, while inhibiting the expression of PINK1 and BNIP3, to further determine whether the protective effects of MEL are associated with its effect on mitophagy. We found that when the expression of PINK1 and BNIP3 was inhibited, MEL intervention could not reduce mtDNA leakage and the release of inflammatory factors caused by PQ exposure, suggesting that the protective effect of MEL was blocked. These results suggest that by promoting the expression of PINK1 and BNIP3 and activating mitophagy, MEL can reduce mtDNA/TLR9-mediated acute lung injury during PQ poisoning. The results of this study could provide guidance for the clinical treatment of PQ poisoning to reduce associated mortality.

DoE development of ionic gradient liposomes: A successful approach to improve encapsulation, prolong anesthesia and decrease the toxicity of etidocaine

Etidocaine (EDC) is a long-acting local anesthetic of the aminoamide family whose use was discontinued in 2008 for alleged toxicity issues. Ionic gradient liposomes (IGL) are nanostructured carriers for which an inner/outer gradient of ions increases drug upload. This work describes IGL_EDC, a formulation optimized by Design of Experiments, composed of hydrogenated soy phosphatidylcholine:cholesterol:EDC, and characterized by DLS, NTA, TEM/Cryo-TEM, DSC and ¹H NMR. The optimized IGL showed significant encapsulation efficiency (41 %), good shelf stability (180 days) and evidence of EDC interaction with the lipid bilayer (as seen by DSC and ¹H NMR results) that confirms its membrane permeation. In vitro (release kinetics and cytotoxicity) tests showed that the encapsulation of EDC into the IGL promoted sustained release for 24 h and decreased by 50 % the intrinsic toxicity of EDC to Schwann cells. In vivo IGL_EDC decreased the toxicity of EDC to Caenorhabditis elegans by 25 % and extended its anesthetic effect by one hour, after infiltrative administration, at clinically used (0.5 %) concentration, in rats. Thus, this novel drug delivery system is a promise for the possible reintroduction of EDC in clinics, aiming at the control of operative and postoperative pain.

Caenorhabditis elegans as a Prediction Platform for Nanotechnology-Based Strategies: Insights on Analytical Challenges

Nanotechnology-based strategies have played a pivotal role in innovative products in different technological fields, including medicine, agriculture, and engineering. The redesign of the nanometric scale has improved drug targeting and delivery, diagnosis, water treatment, and analytical methods. Although efficiency brings benefits, toxicity in organisms and the environment is a concern, particularly in light of global climate change and plastic disposal in the environment. Therefore, to measure such effects, alternative models enable the assessment of impacts on both functional properties and toxicity. Caenorhabditis elegans is a nematode model that poses valuable advantages such as transparency, sensibility in responding to exogenous compounds, fast response to perturbations besides the possibility to replicate human disease through transgenics. Herein, we discuss the applications of C. elegans to nanomaterial safety and efficacy evaluations from one health perspective. We also highlight the directions for developing appropriate techniques to safely adopt magnetic and organic nanoparticles, and carbon nanosystems. A description was given of the specifics of targeting and treatment, especially for health purposes. Finally, we discuss C. elegans potential for studying the impacts caused by nanopesticides and nanoplastics as emerging contaminants, pointing out gaps in environmental studies related to toxicity, analytical methods, and future directions.

Safety assessment of different unloaded polymeric nanocapsules in Caenorhabditis elegans

Nano-sized drug delivery systems have been the subject of intense research in recent years because polymeric materials allow the absorption and release of active substances in a controlled manner. Despite the benefits, the safety of nanoparticulate systems is an aspect to be understood, particularly in vivo systems. Caenorhabditis elegans is a very useful alternative model for nanotoxicology and has been recently applied in this field. The aim of this study was to evaluate toxicological endpoints in C. elegans exposed to nanocapsules (NC) prepared with different coatings: polysorbate 80 (NCP80); polyethylene glycol (NCPEG), Eudragit® RS 100 (NCEUD) and chitosan (NCCS). Nanocapsules were prepared by nanoprecipitation method and showed acceptable physico-chemical characterization. Polyethylene glycol nanocapsules and chitosan nanocapsules increased worms lethality in a dose-dependent manner in acute exposure; polysorbate 80 nanocapsules, polyethylene glycol nanocpsules and chitonan nanocapsules also increased lethality following chronic exposure. Chitosan nanocapsules were the most toxic in all exposures, demonstrating toxicity even at low concentrations. Reproduction and body length were not affected by any of the nanocapsules exposures. The expression of superoxide dismutase showed that polysorbate 80 nanocapsules at the highest concentration slightly increased SOD-3::GFP expression. On the other hand, chitosan nanocapsules exposure blunted SOD-3 expression. This work demonstrates the toxicological differences between nanocapsule produced with different coatings and indicates higher safety for the use of eugragit nanocapsule in new formulations for future drug delivery and targeting systems.

AdoR-1 (Adenosine Receptor) Contributes to Protection against Paraquat-Induced Oxidative Stress in Caenorhabditis elegans

AdoR-1, the single adenosine receptor homolog in Caenorhabditis elegans, which belongs to the superfamily of G-protein coupled receptors (GPCRs), mediates most of the physiological effects of extracellular adenosine. Adenosine has been proved to improve the survival rate of C. elegans in oxidative stress conditions. However, the potential mechanism of adenosine's protective effect against oxidative stress via AdoR-1 has not been studied. In this study, C. elegans were divided into three groups: two groups with paraquat treatment, one in the presence and one in the absence of adenosine, and an untreated control group. Results indicate that many differentially expressed genes were found to be enriched significantly in neural-related signaling pathways among transcriptome data of three groups. Further gene network analysis showed that some important genes well known to be involved in promoting the acetylcholine release pathway, such as dop-1, egl-30, and unc-13, and those involved in promoting the neuropeptide release pathway, such as kin-1, were upregulated by paraquat induction but downregulated after adenosine treatment. Meanwhile, a completely opposite trend was observed for the goa-1 gene that inhibits the acetylcholine-release and neuropeptide-release pathway. Additionally, some biochemical assays including SOD, GSSG, GSH, and AChE were measured to identify the potential protection of adenosine against oxidative stress between wild-type strain N2 and ador-1 gene knockout strain EG6890. Conclusively, our study revealed series of adenosine receptor-mediated genes in C. elegans that might act as regulators of paraquat-induced oxidative stress and may indicate adenosine's promising protective effects.

Phytochemical composition and anti-aging activity of n-butanol extract of Hedyotis diffusa in Caenorhabditis elegans

Hedyotis diffusa Willd. ( H. diffusa ), a kind of traditional Chinese medicine, has been evaluated to potential display antioxidant and anti-aging effects in vitro experiments. In this work, we investigated the effects on lifespan and stress resistance of the N-butanol extract from H. diffusa (NHD) in vivo using a Caenorhabditis elegans ( C. elegans ) model. The phytochemicals of NHD were identified by UPLC-ESI-qTOF-MS/MS method. NHD-treated wild-type N2 worms showed an increase in survival time under both normal and stress conditions. Meanwhile, NHD promoted the healthspan of nematodes by stimulating growth and development, reducing the deposition of age pigment, increasing the activities of superoxide dismutase (SOD) and glutathione peroxidase dismutase (GSH-Px), and decreasing the level of ROS without impairing fertility. Moreover, the upregulating of the expression of daf-16 , gst-4 , sod-3 , hsp12.6 genes and the downregulating of the expression of daf-2 were involved in the NHD-mediated lifespan extension. Finally, the increasing of the expression of GST-4::GFP in CL2166 transgenic nematodes and the life-span-extending activity of NHD was completely abolished in daf-2 and daf-16 mutants further revealed that the potential roles for these genes in NHD-induced longevity in C. elegans . Collectively, our findings suggest that NHD may have an active effect in healthy aging and age-related diseases.

A Review on Conventional and Advanced Methods for Nanotoxicology Evaluation of Engineered Nanomaterials

Nanotechnology can be defined as the field of science and technology that studies material at nanoscale (1-100 nm). These nanomaterials, especially carbon nanostructure-based composites and biopolymer-based nanocomposites, exhibit excellent chemical, physical, mechanical, electrical, and many other properties beneficial for their application in many consumer products (e.g., industrial, food, pharmaceutical, and medical). The current literature reports that the increased exposure of humans to nanomaterials could toxicologically affect their environment. Hence, this paper aims to present a review on the possible nanotoxicology assays that can be used to evaluate the toxicity of engineered nanomaterials. The different ways humans are exposed to nanomaterials are discussed, and the recent toxicity evaluation approaches of these nanomaterials are critically assessed.

Melatonin-Loaded Nanocarriers: New Horizons for Therapeutic Applications

The use of nanosized particles has emerged to facilitate selective applications in medicine. Drug-delivery systems represent novel opportunities to provide stricter, focused, and fine-tuned therapy, enhancing the therapeutic efficacy of chemical agents at the molecular level while reducing their toxic effects. Melatonin (N-acetyl-5-methoxytriptamine) is a small indoleamine secreted essentially by the pineal gland during darkness, but also produced by most cells in a non-circadian manner from which it is not released into the blood. Although the therapeutic promise of melatonin is indisputable, aspects regarding optimal dosage, biotransformation and metabolism, route and time of administration, and targeted therapy remain to be examined for proper treatment results. Recently, prolonged release of melatonin has shown greater efficacy and safety when combined with a nanostructured formulation. This review summarizes the role of melatonin incorporated into different nanocarriers (e.g., lipid-based vesicles, polymeric vesicles, non-ionic surfactant-based vesicles, charge carriers in graphene, electro spun nanofibers, silica-based carriers, metallic and non-metallic nanocomposites) as drug delivery system platforms or multilevel determinations in various in vivo and in vitro experimental conditions. Melatonin incorporated into nanosized materials exhibits superior effectiveness in multiple diseases and pathological processes than does free melatonin; thus, such information has functional significance for clinical intervention.

Use of nontarget organism Chironomus sancticaroli to study the toxic effects of nanoatrazine

Atrazine was banned by the European Union in 2004, but is still used in many countries. Agricultural research employing nanotechnology has been developed in order to reduce the impacts to the environment and nontarget organisms. Nanoatrazine was developed as a carrier system and have been considered efficient in weed control. However, its toxicity must be verified with nontarget organisms. In this context, the aim of the present study was to investigate ecotoxicological effects of solid lipid nanoparticles (empty and loaded with atrazine) and atrazine on Chironomus sancticaroli larvae, evaluating the endpoints: mortality, mentum deformity, development rate and biochemical biomarkers. The contaminant concentrations used were 2, 470, 950, and 1900 μg L^-1 in acute (96 h) and 2 μg L^-1 in subchronic (10 days) bioassays. An environmentally relevant concentration of atrazine (2 μg L^-1) presented toxic and lethal effects towards the larvae. The nanoparticles loaded with atrazine showed toxic effects similar to free atrazine, causing mortality and biochemical alterations on the larvae. The nanoparticle without atrazine caused biochemical alterations and mortality, indicating a possible toxic effect of the formulation on the larvae. In the acute bioassay, most concentrations of nanoparticles loaded with atrazine were not dose dependent for the endpoint mortality. Only the atrazine concentration of 470 μg L^-1 was statistically significant to endpoint mentum deformity. The atrazine and nanoparticles (with and without atrazine) did not affect larval development. The results indicate that Chironomus sancticaroli was sensitive to monitor nanoatrazine, presenting potential to be used in studies of toxicity of nanopesticides.

In vitro and in vivo anti-inflammatory activity and chemical composition of Renealmia petasites Gagnep

The study aimed to investigate the chemical composition and the anti-inflammatory activity of the hydroethanolic rhizomes, stems, and leaf extracts of Renealmia petasites using in vitro and in vivo assays. The chemical composition of the extracts was characterized in a linear iron trap mass spectrometer. Total phenolic, flavonoid, and tannin content were determined by spectrophotometry analyses. In vitro anti-inflammatory activity was investigated in lipopolysaccharide-stimulated macrophages evaluating the influence on the production of superoxide anion (O₂^-), nitric oxide (NO), and the pro-inflammatory cytokines tumor necrosis factor (TNF-α) and interleukin-6 (IL-6). In vivo effects were determined using the air pouch model in which were inoculated carrageenan and thereafter treated with 50 mg/kg of the hydroethanolic extracts of R. petasites. After 4 and 24 h, the cellular influx, protein exudation, cytokines, and nitric oxide were evaluated. Eight compounds were tentatively identified in the R. petasites extracts, suggesting five diarylheptanoids, one flavonoid, and two fatty alcohols. The in vitro results showed that the extracts were capable of blocking free radicals and/or inhibiting their intracellular actions by inhibiting the production of important mediators of the inflammatory process, such as NO, O₂^-, TNF-α, and IL-6. In vivo, R. petasites significantly decrease the influx of leukocytes, mainly neutrophils, protein exudation, NO, TNF-α, and IL-6 concentration in the air pouch model. The results evidenced that R. petasites can be considered a promising alternative therapy for the treatment and management of osteoarthritis and other inflammatory diseases.

Phenolic compounds and antioxidant activity in vitro and in vivo of Butia and Opuntia fruits

Despite the consumption recommendations and the potential health benefits, Brazilian biodiversity has a large number of fruit species that are still unexplored, such as Butia catarinensis (Butiá da Praia), Butia eriospatha (Butiá da Serra) and Opuntia elata (Arumbeva). The phenolic compounds of these fruits were determined by HPLC-DAD-MS/MS. Morever, in vitro assays of antioxidant capacity on hydroethanolic extracts against hydrogen peroxide (H₂O₂), hydroxyl (OH), peroxyl (ROO) and ABTS radicals were evaluated. In vivo assays evaluating the survival of worms and reactive oxygen species (ROS) generation were performed using the nematode Caenorhabditis elegans. Eighteen, twenty-eight and seventeen phenolic compounds were identified in Butiá da Praia, Butiá da Serra and Arumbeva, respectively. The main groups of phenolic compounds found in the fruits were hydroxybenzoic acids (60.5, 26.5 and 96.1% of the total phenolic compounds for Butiá da Praia, Butiá da Serra and Arumbeva, respectively), flavan-3-ols (23.6 and 61.2% of the total phenolic compounds for Butiá da Praia and Butiá da Serra) and flavonols (2.6% of the total phenolic compounds for Arumbeva). The hydroethanolic extracts of these fruits were free radical scavenger, sources of phenolic compounds and did not cause toxic effects in vivo. In hydroethanolic extracts of Butiá da Praia and Arumbeva, the total phenolic content increased by around 67% and 35%, respectively. Besides the health benefits, these proved to be promising sources of natural antioxidants, with phenolic composition variating among species and collection site. The obtained results enable future applications of studied fruits extracts in food and/or pharmaceutical products, encouraging and valuing the sustainable use of biodiversity.

In Vitro and In Vivo Models for Evaluating the Oral Toxicity of Nanomedicines

Toxicity studies for conventional oral drug formulations are standardized and well documented, as required by the guidelines of administrative agencies such as the US Food & Drug Administration (FDA), the European Medicines Agency (EMA) or European Medicines Evaluation Agency (EMEA), and the Japanese Pharmaceuticals and Medical Devices Agency (PMDA). Researchers tend to extrapolate these standardized protocols to evaluate nanoformulations (NFs) because standard nanotoxicity protocols are still lacking in nonclinical studies for testing orally delivered NFs. However, such strategies have generated many inconsistent results because they do not account for the specific physicochemical properties of nanomedicines. Due to their tiny size, accumulated surface charge and tension, sizeable surface-area-to-volume ratio, and high chemical/structural complexity, orally delivered NFs may generate severe topical toxicities to the gastrointestinal tract and metabolic organs, including the liver and kidney. Such toxicities involve immune responses that reflect different mechanisms than those triggered by conventional formulations. Herein, we briefly analyze the potential oral toxicity mechanisms of NFs and describe recently reported in vitro and in vivo models that attempt to address the specific oral toxicity of nanomedicines. We also discuss approaches that may be used to develop nontoxic NFs for oral drug delivery.

Ochratoxin A presence in Cabernet Sauvignon wine changes antioxidant activity in vitro and oxidative stress markers in vivo

Ochratoxin A (OTA) is a mycotoxin found in grape products and oxidative stress has been reported as an important mechanism involved in its toxicity, classified as possible carcinogenic to humans. Conversely, phenolics are known bioactive compounds in grapes and display great antioxidant properties. However, the biological effects of the concomitant presence of phenolic compounds and OTA remains unclear. The aim of this study was to evaluate, for the first time, the effect of OTA presence in Cabernet Sauvignon wine on antioxidant activity in vitro and on oxidative stress markers in vivo. In addition, the phenolic composition of wine was evaluated by LC-DAD-MS/MS. In vitro assays were based on spectrophotometric methods, while in vivo assays were performed evaluating oxidative stress markers in the nematode Caenorhabditis elegans, an alternative model to animal testing. A total of 23 phenolic compounds were identified in the Cabernet sauvignon red wine, including the anthocyanins delphinidin-3-O-glicoside and malvidin-3-O-glicoside, the flavonol quercetin-3-O-glucuronide and the phenolic acids caffeic, verbascoside and caftaric. Trans-resveratrol and trans-piceid were the only stilbenes found in the samples. OTA presence in the red wine was accompanied by reduction in GSH content and increase in hydroxyl radical generation in vitro. The presence of OTA in wine also increased lipoperoxidation and induced overexpression of the antioxidant enzymes superoxide dismutase and catalase in vivo. This study demonstrates that OTA presence in red wine can reduce its antioxidant potential in vitro and induces oxidative stress in vivo, without affecting the phenolic compounds levels in the samples. Thus, this work provides insights into the negative effects of the presence of OTA in wine, not only by its known toxicity, but also by prejudicing the antioxidant potential of wine. It is important to be aware of these effects when developing a complete description of OTA toxicity in humans.

The Protective Effect of Adenosine-Preconditioning on Paraquat-Induced Damage in Caenorhabditis elegans

Adenosine plays an important role in the physiological and pathological conditions of the body by combining different types of adenosine receptors widely distributed in various tissues in the body. In present study, an acute model for paraquat-poisoning in Caenorhabditis elegans was established for quantitative assessment via a time-dose-mortality (TDM) modeling technique with various paraquat doses over 8 hours. Adenosine was first used to precondition at high, medium, and low concentrations and the survival rate of C. elegans was recorded to evaluate adenosine antistress protection against paraquat damage. The results revealed that the TDM model was good for the quantitative assessment of paraquat-poisoning on C. elegans based on the Hosmer-Lemeshow test for homogeneity of modeling (P = .38). The survival rates of adenosine-preconditioned C. elegans have a dose-dependent association with adenosine concentration. At 3000 μM (high concentration) and 300 μM (medium concentration), adenosine-preconditioned C. elegans still had survival rates of 5.38% ± 1.68% and 5.0% ± 1.19% in the subsequent 8 hours observation period. On the contrary, the survival rates of those receiving 30 μM (low concentration) and the 0 μM (unpreconditioned treatment) were zero. To conclude, adenosine preconditioning had protective effects on C. elegans intoxicated with paraquat by decreasing its mortality rate.

Hydrogen extends Caenorhabditis elegans longevity by reducing reactive oxygen species

At present, a large number of studies have reported that hydrogen has antioxidant functions and prevents oxidative stress damage. However, it is not clear whether hydrogen can prolong longevity based on these effects. Therefore, we studied and explored the antiaging potential of exogenous hydrogen and its ability to extend longevity using Caenorhabditis elegans (C. elegans) as an animal model. Our results showed that the lifespans of the N2, sod-3 and sod-5 mutant strains were extended by approximately 22.7%, 9.5%, and 8.7%, respectively, after hydrogen treatment, but hydrogen had no effect on the lifespans of the daf-2 and daf-16 mutant strains. Meanwhile, the level of reactive oxygen species (ROS) in the hydrogen treatment group was significantly lower than that in the control group. At the transcript level, the expression of age-1 and let-363 was obviously decreased, while the expression of ins-18 was increased at the same time point (14 d). Compared with the control group, paraquat (PQ) could reduce the lifespan of the N2 and sod-5 mutant strains. Importantly, the longevity of these mutant strains recovered to normal levels when the animals were treated with exogenous hydrogen. According to these results, the lifespan of C. elegans is closely related to oxidative stress and can be significantly prolonged by reducing oxidative stress damage. Taken together, our data showed that hydrogen is a valuable antioxidant that can significantly reduce the body’s ROS levels and extend the lifespan of C. elegans. This study also laid a foundation for the subsequent application of hydrogen in antiaging studies.

Toxicity of nonylphenol and nonylphenol ethoxylate on Caenorhabditis elegans

Among the most used chemicals in the world are nonionic surfactants. One of these environmental pollutants is nonylphenol ethoxylate (NP-9), also known as Tergitol, and its degradation product, nonylphenol (NP). The objective of this work was to determine the toxicity of NP and NP-9 in Caenorhabditis elegans. Wild-type L4 larvae were exposed to different concentrations of the surfactants to measure functional endpoints. Mutant strains were employed to promote the activation of toxicity signaling pathways related to mtl-2, gst-1, gpx-4, gpx-6, sod-4, hsp-70 and hsp-4. Additionally, stress response was also assessed using a daf-16::GFP transgenic strain. The lethality was concentration dependent, with 24-h LC₅₀ of 122 μM and 3215 μM for NP and NP-9, respectively. Both compounds inhibited nematode growth, although NP was more potent; and at non-lethal concentrations, nematode locomotion was reduced. The increase in the expression of tested genes was significant at 10 μM for NP-9 and 0.001 μM for NP, implying a likely role for the activation of oxidative and cellular stress, as well as metabolism pathways. With the exception of glutathione peroxidase, which has a bimodal concentration-response curve for NP, typical of endocrine disruption, the other curves for this xenobiotic in the strains evaluated were almost flat for most concentrations, until reaching 50-100 μM, where the effect peaked. NP and NP-9 induced the activation and nuclear translocation of DAF-16, suggesting that transcription of stress-response genes may be mediated by the insulin/IGF-1 signaling pathway. In contrast, NP-9 induced a concentration-dependent response for the sod-4 and hsp-4 mutants, with greater fluorescence induction than NP at similar levels. In short, NP and NP-9 affect the physiology of C. elegans and modulate gene expression related to ROS production, cellular stress and metabolism of xenobiotics.

Melatonin-loaded lipid-core nanocapsules protect against lipid peroxidation caused by paraquat through increased SOD expression in Caenorhabditis elegans

BACKGROUND

Melatonin has been described in the literature as a potent antioxidant. However, melatonin presents variable, low bioavailability and a short half-life. The use of polymeric nanoparticulated systems has been proposed for controlled release. Thus, the purpose of this study was to investigate the action of melatonin-loaded lipid-core nanocapsules (Mel-LNC) in the antioxidant system of Caenorhabditis elegans, and the possible protective effect of this formulation against lipid peroxidation caused by paraquat (PQ).

METHODS

The suspensions were prepared by interfacial deposition of the polymer and were physiochemically characterized. C. elegans N2 wild type and transgenic worm CF1553, muls84 [sod-3p::gfp; rol6(su1006)] were obtained from the Caenorhabditis Genetics Center (CGC). The worms were divided into 5 groups: Control, PQ 0.5 mM, PQ 0.5 mM + Mel-LNC 10 μg/mL, PQ + unloaded lipid-core nanocapsules (LNC), and PQ + free melatonin (Mel) 10 μg/mL. The lipid peroxidation was assessed through thiobarbituric acid (TBARS) levels and the fluorescence levels of the transgenic worms expressing GFP were measured.

RESULTS

The LNC and Mel-LNC presented a bluish-white liquid, with pH values of 5.56 and 5.69, respectively. The zeta potential was - 6.4 ± 0.6 and - 5.2 ± 0.2, respectively. The mean particle diameter was 205 ± 4 nm and 203 ± 3 nm, respectively. The total melatonin content was 0.967 mg/ml. The TBARS levels were significantly higher in the PQ group when compared to the control group (p < 0.001). Mel-LNC reduced TBARS levels to similar levels found in the control group. Moreover, only Mel-LNC significantly enhanced the SOD-3 expression (p < 0.05). Mel-LNC was capable of protecting C. elegans from lipid peroxidation caused by PQ and this was not observed when free melatonin was used. Moreover, Mel-LNC increased the fluorescence intensity of the transgenic strain that encodes the antioxidant enzyme SOD-3, demonstrating a possible mechanism of protection from PQ-induced damage.

CONCLUSION

These findings demonstrated that melatonin, when associated with nanocapsules, had improved antioxidant properties and the protective activity against PQ-induced lipid peroxidation could be associated with the activation of antioxidant enzymes by Mel-LNC in C. elegans.

Caenorhabditis elegans as a complete model organism for biosafety assessments of nanoparticles

The number of biosafety evaluation studies of nanoparticles (NPs) using different biological models is increasing with the rapid development of nanotechnology. Thus far, nematode Caenorhabditis elegans (C. elegans), as a complete model organism, has become an important in vivo alternative assay system to assess the risk of NPs, especially at the environmental level. According to results of qualitative and quantitative analyses, it can be concluded that studies of nanoscientific research using C. elegans is persistently growing. However, the comprehensive conclusion and analysis of toxic effects of NPs in C. elegans are limited and chaotic. This review focused on the effects, especially sublethal ones, induced by NPs in C. elegans, including the development, intestinal function, immune response, neuronal function, and reproduction, as well as the underlying mechanisms of NPs causing these effects, including oxidative stress and alterations of several signaling pathways. Furthermore, we presented some factors that influence the toxic effects of NPs in C. elegans. The advantages and limitations of using nematodes in the nanotoxicology study were also discussed. Finally, we predicted that the application of C. elegans to assess long-term impacts of metal oxide NPs in the ecosystem would become a vital part of the nanoscientific research field, which provided an insight for further study.

Co-nanoencapsulation of antimalarial drugs increases their in vitro efficacy against Plasmodium falciparum and decreases their toxicity to Caenorhabditis elegans

Drugs used for the treatment and prevention of malaria have resistance-related problems, making them ineffective for monotherapy. If properly associated, many of these antimalarial drugs may find their way back to the treatment regimen. Among the therapeutic arsenal, quinine (QN) is a second-line treatment for uncomplicated malaria but has side effects that limit its use. Curcumin (CR) is a natural compound with anti-plasmodial activities and low bioavailability. In this context, the aim of this work was to develop and characterize co-encapsulated QN + CR-loaded polysorbate-coated polymeric nanocapsules (NC-QC) to evaluate their activity on Plasmodium falciparum and the safety of the nanoformulations for Caenorhabditis elegans. NC-QC displayed a diameter of approximately 200 nm, a negative zeta potential and a slightly basic pH. The drugs are homogeneously distributed in the NCs in the amorphous form. Co-encapsulated NCs exhibited a significant reduction in P. falciparum parasitemia, better than QN/CR. The worms exposed to NC-QC showed higher survival and longevity and no decrease in their reproductive capacity compared to free and associated drugs. It was possible to prove that the NCs were absorbed orally by the worms using fluorescence microscopy. Co-encapsulation of QN and CR was effective against P. falciparum, minimizing the toxic effects caused by chronic exposure of the free drugs in C. elegans.

Use of nanoparticle concentration as a tool to understand the structural properties of colloids

Elucidation of the structural properties of colloids is paramount for a successful formulation. However, the intrinsic dynamism of colloidal systems makes their characterization a difficult task and, in particular, there is a lack of physicochemical techniques that can be correlated to their biological performance. Nanoparticle tracking analysis (NTA) allows measurements of size distribution and nanoparticle concentration in real time. Its analysis over time also enables the early detection of physical instability in the systems not assessed by subtle changes in size distribution. Nanoparticle concentration is a parameter with the potential to bridge the gap between in vitro characterization and biological performance of colloids, and therefore should be monitored in stability studies of formulations. To demonstrate this, we have followed two systems: extruded liposomes exposed to increasing CHCl₃ concentrations, and solid lipid nanoparticles prepared with decreasing amounts of poloxamer 188. NTA and dynamic light scattering (DLS) were used to monitor changes in nanoparticle number and size, and to estimate the number of lipid components per particle. The results revealed a strong negative correlation between particle size (determined by DLS) and concentration (assessed by NTA) in diluted samples, which should be adopted to monitor nanocolloidal stability, especially in drug delivery.

Arginylglycylaspartic Acid-Surface-Functionalized Doxorubicin-Loaded Lipid-Core Nanocapsules as a Strategy to Target Alpha(V) Beta(3) Integrin Expressed on Tumor Cells

Doxorubicin (Dox) clinical use is limited by dose-related cardiomyopathy, becoming more prevalent with increasing cumulative doses. Previously, we developed Dox-loaded lipid-core nanocapsules (Dox-LNC) and, in this study, we hypothesized that self-assembling and interfacial reactions could be used to obtain arginylglycylaspartic acid (RGD)-surface-functionalized-Dox-LNC, which could target tumoral cells overexpressing αvβ3 integrin. Human breast adenocarcinoma cell line (MCF-7) and human glioblastoma astrocytoma (U87MG) expressing different levels of αvβ3 integrin were studied. RGD-functionalized Dox-LNC were prepared with Dox at 100 and 500 mg·mL-1 (RGD-MCMN (Dox100) and RGD-MCMN (Dox500)). Blank formulation (RGD-MCMN) had z-average diameter of 162 ± 6 nm, polydispersity index of 0.11 ± 0.04, zeta potential of +13.2 ± 1.9 mV and (6.2 ± 1.1) × 1011 particles mL-1, while RGD-MCMN (Dox100) and RGD-MCMN (Dox500) showed respectively 146 ± 20 and 215 ± 25 nm, 0.10 ± 0.01 and 0.09 ± 0.03, +13.8 ± 2.3 and +16.4 ± 1.5 mV and (6.9 ± 0.6) × 1011 and (6.1 ± 1.0) × 1011 particles mL-1. RGD complexation was 7.73 × 10⁴ molecules per nanocapsule and Dox loading were 1.51 × 10⁴ and 7.64 × 10⁴ molecules per nanocapsule, respectively. RGD-functionalized nanocapsules had an improved uptake capacity by U87MG cells. Pareto chart showed that the cell viability was mainly affected by the Dox concentration and the period of treatment in both MCF-7 and U87MG. The influence of RGD-functionalization on cell viability was a determinant factor exclusively to U87MG.

Microcystin-LR exposure induces oxidative damage in Caenorhabditis elegans: Protective effect of lutein extracted from marigold flowers

Microcystin-LR (MIC-LR) is a hepatotoxin, with toxicity mechanisms linked to oxidative stress. Besides, neurotoxic effects of MIC-LR have recently been described. Herein, we evaluated the effects of environmentally important concentrations of MIC-LR (1, 10, 100, 250, and 500 μg/L) on oxidative stress markers and the survival rate of the nematode Caenorhabditis elegans (C. elegans). In addition, a possible protective effect of the carotenoid lutein (LUT) extracted from marigold flowers against MIC-LR toxicity was investigated. Higher concentrations (250 and 500 μg/L) of MIC-LR induced the generation of reactive oxygen species (ROS) and resulted in a survival loss in C elegans. Meanwhile, all MIC-LR concentrations caused an increase in the superoxide dismutase (SOD) expression, while catalase (CAT) expression was only affected at 500 μg/L. The carotenoid LUT prevented the ROS generation, impairment in the CAT expression, and the survival loss induced by MIC-LR in C. elegans. Our results confirm the toxicity of MIC-LR even in a liver-lacking invertebrate and the involvement of oxidative events in this response. Additionally, LUT appears to be able to mitigate the MIC-LR toxic effects.

Toxicity-based toxicokinetic/toxicodynamic assessment of bioaccumulation and nanotoxicity of zerovalent iron nanoparticles in Caenorhabditis elegans

Elucidating the relationships between the toxicity-based-toxicokinetic (TBTK)/toxicodynamic (TD) properties of engineered nanomaterials and their nanotoxicity is crucial for human health-risk analysis. Zerovalent iron (Fe⁰) nanoparticles (NPs) are one of the most prominent NPs applied in remediating contaminated soils and groundwater. However, there are concerns that Fe⁰NP application contributes to long-term environmental and human health impacts. The nematode Caenorhabditis elegans is a surrogate in vivo model that has been successfully applied to assess the potential nanotoxicity of these nanomaterials. Here we present a TBTK/TD approach to appraise bioaccumulation and nanotoxicity of Fe⁰NPs in C. elegans. Built on a present C. elegans bioassay with estimated TBTK/TD parameters, we found that average bioconcentration factors in C. elegans exposed to waterborne and food-borne Fe⁰NPs were ~50 and ~5×10^-3, respectively, whereas 10% inhibition concentrations for fertility, locomotion, and development, were 1.26 (95% CI 0.19-5.2), 3.84 (0.38-42), and 6.78 (2.58-21) μg·g^-1, respectively, implicating that fertility is the most sensitive endpoint in C. elegans. Our results also showed that biomagnification effects were not observed in waterborne or food-borne Fe⁰NP-exposed worms. We suggest that the TBTK/TD assessment for predicting NP-induced toxicity at different concentrations and conditions in C. elegans could enable rapid selection of nanomaterials that are more likely to be nontoxic in larger animals. We conclude that the use of the TBTK/TD scheme manipulating C. elegans could be used for rapid evaluation of in vivo toxicity of NPs or for drug screening in the field of nanomedicine.

Safety assessment of nanopesticides using the roundworm Caenorhabditis elegans

The extensive use of pesticides is causing environmental pollution, affecting animal organisms in different habitats and also leading human health at risk. In this study, we present as an alternative the use of nanoparticles loaded with pesticides and report their toxicological assessment to a soil organism, Caenorhabditis elegans. Three nanoparticle formulations were analyzed: solid lipid nanoparticles loaded or not with atrazine and simazine, SLN; polymeric nanoparticles, NC_PCL loaded with atrazine; and chitosan/tripolyphosphate, CS/TPP, loaded or not with paraquat. All formulations, loaded or not with pesticides, increased lethality in a dose- dependent manner with similar LC50. Both loaded and unloaded NC_PCL were the most toxic formulations to developmental rate, significantly reducing worms length, even at low concentrations. In contrast, both CS/TPP nanoparticles were the least toxic, not affecting reproduction and body length at higher concentrations, probably due to the biocompatibility of chitosan. The physico-chemical characterization of nanoparticles after incubation in saline solution (used in exposure of organisms) has shown that these colloidal systems are stable and remain with the same initial characteristics, even in the presence of saline environment. Notably, our results indicate that the observed effects were caused by the nanoparticles per se. These results suggest that the development of nanoparticles aiming agriculture applications needs more studies in order to optimize the composition and then reduce their toxicity to non-target organisms.

DNA damage in the elderly is associated with 5-MTHF levels: a pro-oxidant activity

The aging phenomenon is associated with oxidative stress damage in biomolecules, especially DNA. 5-Methyltetrahydrofolate (5-MTHF), the active folate form, plays a pivotal role in maintaining genomic integrity. However, recently it was associated with cancer development. In Brazil, there are folic acid enriched foods, such as flour, making the general population chronically exposed to folates. Therefore, the aim of this study was to investigate whether erythrocytes 5-MTHF levels were associated with age-related DNA damage in two groups (elderly and young subjects). Additionally, a study in Caenorhabditis elegans, an in vivo alternative model, was performed to verify if 5-MTHF presents a pro-oxidant effect. A total of 50 elderly and 25 young subjects participated in this study, which analyzed whole blood DNA damage, plasma carbonyl proteins (PCO), and erythrocytes 5-MTHF levels. In addition, ROS and RNS production, survival rate, and lifespan were performed in C. elegans exposed to 5-MTHF. Blood 5-MTHF levels and DNA damage were increased in the elderly compared to the young group. A positive association was found between 5-MTHF levels and DNA damage, and between DNA damage and PCO levels, suggesting an oxidative cause of damage associated with the active folate form. In an experimental study it was observed that 5-MTHF increased ROS production in C. elegans, in a dose dependent manner, while survival rate and life span were not affected at the test doses. These findings suggest that 5-MTHF, the active folate form, may be involved in DNA damage in the elderly. This damage could be a result of oxidative stress, as observed in the in vivo alternative model; however, more studies are necessary to prove our present results.

Liquid formulation containing doxorubicin-loaded lipid-core nanocapsules: Cytotoxicity in human breast cancer cell line and in vitro uptake mechanism

Cancer is a major public health problem in the world, being breast cancer the most frequent cancer affecting women. Despite advances in detection and treatment, mortality rates remain high. Therefore, new approaches for breast cancer treatments are necessary. In this study, our objective was to develop a liquid formulation containing doxorubicin-loaded lipid-core nanocapsules (DOX-LNC), to evaluate the in vitro antiproliferative activity and to determine the nanocapsules uptake by MCF-7 cells. Lipid-core nanocapsules (LNC), blank formulation, and DOX-LNC, proposed treatment, were prepared by self-assembling using the solvent displacement method. Hydrodynamic mean diameters (z-average) were respectively 191±31nm and 230±23nm presenting narrow size distributions. Drug content was 0.102±0.029mgmL^-1 with an encapsulation efficiency higher than 90%. Formulations were applied to semiconfluent MCF-7 cells. After 24h, LNC showed no cytotoxicity, while DOX-LNC showed an IC₅₀ of 4.49 micromolar. After 72h of incubation, DOX-LNC showed an IC₅₀ of 1.60 micromolar demonstrating a sustained effect. The nanocapsules were internalized by endocytosis mediated by caveolin and by fluid phase endocytosis, which are active transport mechanisms. In conclusion, the liquid formulation containing DOX-LNC showed to be a promising product for the breast cancer treatment opening new avenues for further in vivo studies.

Selective growth inhibition of cancer cells with doxorubicin-loaded CB[7]-modified iron-oxide nanoparticles

Cucurbit[7]uril-modified iron-oxide nanoparticles (CB[7]NPs) were loaded with doxorubicin hydrochloride (Dox) and tested as a drug delivery system.

In vitro toxicity assessment of oral nanocarriers

The fascinating properties of nanomaterials opened new frontiers in medicine. Nanocarriers are useful systems in transporting drugs to site-specific targets. The unique physico-chemical characteristics making nanocarriers promising devices to treat diseases may also be responsible for potential adverse effects. In order to develop functional nano-based drug delivery systems, efficacy and safety should be carefully evaluated. To date, no common testing strategy to address nanomaterial toxicological challenges has been generated. Different cell culture models are currently used to evaluate nanocarrier safety using conventional in vitro assays, but overall they have generated a huge amount of conflicting data. In this review we describe state-of-the-art approaches for in vitro testing of orally administered nanocarriers, highlighting the importance of developing harmonized and validated standard operating procedures. These procedures should be applied in a safe-by-design context with the aim to reduce and/or eliminate the uncertainties and risks associated with nanomedicine development.

Voltammetric determination of melatonin using a graphene-based sensor in pharmaceutical products

Melatonin can be sensitively detected in pharmaceuticals by cyclic voltammetry and fixed-potential amperometry using a graphene-based sensor. The sensor characterization of cyclic voltammetry constantly provides high values of electrode active area and heterogeneous rate constant. In optimal conditions, the sensor was applied for the determination of melatonin in different pharmaceutical samples. The sensitivity to melatonin was 0.0371 A M(-1), and the limit of detection was 0.87×10(-6) M. The data obtained by using the graphene-based sensor for the detection of melatonin in pharmaceutical products were in good agreement with the data provided by the producer. Since no interferences from the excipients were found, using a separation technique was not necessary. Additionally, the low price, ease of handling, small amount of sample, short time per analysis, and possibility of automation are the important advantages that recommend this methodology for quality control of pharmaceuticals.