Safety assessment on polyethylene glycols (PEGs) and their derivatives as used in cosmetic products

Metabolism of alcohol ethoxylates (AEs) in rat, hamster, and human hepatocytes and liver S9: a pilot study for metabolic stability, metabolic pathway, and metabolites identification in vitro and in silico

Alcohol ethoxylates (AEs) are a well-known class of non-ionic surfactants widely used by the personal care market. The aim of this study was to evaluate and characterize the in vitro metabolism of AEs and identify metabolites. Five selected individual homologue AEs (C8EO4, C10EO5, C12EO4, C16EO8, and C18EO3) were incubated using human, rat, and hamster liver S9 fraction and cryopreserved hepatocytes. LC-MS was used to identify metabolites following the incubation of AEs by liver S9 and hepatocytes of all three species. All AEs were metabolized in these systems with a half-life ranging from 2 to 139 min. In general, incubation of AE with human liver S9 showed a shorter half-life compared to rat liver S9. While rat hepatocytes metabolized AEs faster than human hepatocytes. Both hydrophobic alkyl chain and hydrophilic EO head group groups of AEs were found to be target sites of metabolism. Metabolites were identified that show primary hydroxylation and dehydrogenation, followed by O-dealkylation (shortening of EO head groups) and glucuronidation. Additionally, the detection of whole EO groups indicates the cleavage of the ether bond between the alkyl chain and the EO groups as a minor metabolic pathway in the current testing system. Furthermore, no difference in metabolic patterns of each individual homologue AE investigated was observed, regardless of alkyl chain length or the number of EO groups. Moreover, there is an excellent agreement between the in vitro experimental data and the metabolite profile simulations using in silico approaches (OECD QSAR Toolbox). Altogether, these data indicate fast metabolism of all AEs with a qualitatively similar metabolic pathway with some quantitative differences observed in the metabolite profiles. These metabolic studies using different species can provide important reference values for further safety evaluation.

Toxicity of water-soluble polymers polyethylene glycol and polyvinyl alcohol for fish and frog embryos

Personal Care Products (PCPs) have been one of the most studied chemicals in the last twenty years since they were identified as pseudo-persistent pollutants by the European Union in the early 2000s. The accumulation of PCPs in the aquatic environment and their effects on non-target species make it necessary to find new, less harmful, substances. Polyethylene glycol (PEGs) and polyvinyl alcohol (PVAs) are two polymers that have increased their presence in the composition of PCPs in recent years, but little is known about the effect of their accumulation in the environment on non-target species. Through embryotoxicity tests on two common models of aquatic organisms (Danio rerio and Xenopus laevis), this work aims to increase the knowledge of PEGs and PVAs' effects on non-target species. Animals were exposed to the pollutant for 96 h. The main embryotoxicity endpoint (mortality, hatching, malformations, heartbeat rate) was recorded every 24 h. The most significant results were hatching delay in Danio rerio exposed to both chemicals, in malformations (oedema, body malformations, changes in pigmentation and deformations of spine and tail) in D. rerio and X. laevis and significant change in the heartbeat rate (decrease or increase in the rate) in both animals for all chemicals tested.

Substituting Poly(ethylene glycol) Lipids with Poly(2-ethyl-2-oxazoline) Lipids Improves Lipid Nanoparticle Repeat Dosing

Poly(ethylene glycol) (PEG)-lipids are used in Food-and-Drug-Administration-approved lipid nanoparticle (LNP)-RNA drugs, which are safe and effective. However, it is reported that PEG-lipids may also contribute to accelerated blood clearance and rare cases of hypersensitivity; this highlights the utility of exploring PEG-lipid alternatives. Here, it is shown that LNPs containing poly(2-ethyl-2-oxazoline) (PEOZ)-lipids can deliver messenger RNA (mRNA) to multiple cell types in mice inside and outside the liver. In addition, it is reported that LNPs formulated with PEOZ-lipids show reduced clearance from the bloodstream and lower levels of antistealth lipid immunoglobulin Ms than LNPs formulated with PEG-lipids. These data justify further exploration of PEOZ-lipids as alternatives to PEG-lipids in LNP-RNA formulations.

From Personal Care to Coastal Concerns: Investigating Polyethylene Glycol Impact on Mussel's Antioxidant, Physiological, and Cellular Responses

Pharmaceutical and personal care products (PPCPs) containing persistent and potentially hazardous substances have garnered attention for their ubiquitous presence in natural environments. This study investigated the impact of polyethylene glycol (PEG), a common PPCP component, on Mytilus galloprovincialis. Mussels were subjected to two PEG concentrations (E1: 0.1 mg/L and E2: 10 mg/L) over 14 days. Oxidative stress markers in both gills and digestive glands were evaluated; cytotoxicity assays were performed on haemolymph and digestive gland cells. Additionally, cell volume regulation (RVD assay) was investigated to assess physiological PEG-induced alterations. In the gills, PEG reduced superoxide dismutase (SOD) activity and increased lipid peroxidation (LPO) at E1. In the digestive gland, only LPO was influenced, while SOD activity and oxidatively modified proteins (OMPs) were unaltered. A significant decrease in cell viability was observed, particularly at E2. Additionally, the RVD assay revealed disruptions in the cells subjected to E2. These findings underscore the effects of PEG exposure on M. galloprovincialis. They are open to further investigations to clarify the environmental implications of PPCPs and the possibility of exploring safer alternatives.

Benznidazole-Loaded Polymeric Nanoparticles for Oral Chemotherapeutic Treatment of Chagas Disease

Chagas disease (CD) is a worldwide public health problem. Benznidazole (BZ) is the drug used to treat it. However, in its commercial formulation, it has significant side effects and is less effective in the chronic phase of the infection. The development of particulate systems containing BZ is therefore being promoted. The objective of this investigation was to develop polymeric nanoparticles loaded with BZ and examine their trypanocidal impact in vitro. Two formulas (BNP1 and BNP2) were produced through double emulsification and freeze drying. Subsequent to physicochemical and morphological assessment, both formulations exhibited adequate yield, average particle diameter, and zeta potential for oral administration. Cell viability was assessed in H9C2 and RAW 264.7 cells in vitro, revealing no cytotoxicity in cardiomyocytes or detrimental effects in macrophages at specific concentrations. BNP1 and BNP2 enhanced the effect of BZ within 48 h using a treatment of 3.90 μg/mL. The formulations notably improved NO reduction, particularly BNP2. The findings imply that the compositions are suitable for preclinical research, underscoring their potential as substitutes for treating CD. This study aids the quest for new BZ formulations, which are essential in light of the disregard for the treatment of CD and the unfavorable effects associated with its commercial product.

Efficacy and Safety of Neauvia Intense in Correcting Moderate-to-Severe Nasolabial Folds: A Post-Market, Prospective, Open-Label, Single-Centre Study

Purpose

 This prospective, single-center study aims to evaluate the safety and effectiveness of NEAUVIA Intense, a PEG cross-linked polymeric hydrogel, in correcting moderate-to-severe nasolabial folds (NLF) in a routine clinical setting. The study investigates the aesthetic outcomes, patient satisfaction, and adverse events associated with the injectable filler.

Patients and Methods

Seventy patients were initially enrolled, with 60 meeting study parameters. The post-market study involved a single session treatment, employing NEAUVIA Intense on each side of the NLF. Assessments utilized the Modified Fitzpatrick Wrinkle Scale (MFWS), Global Aesthetic Improvement Scale (GAIS), and Visual Analogical Scale (VAS).

Results

 The study demonstrated a statistically significant improvement in tissue depression immediately post-injection (p < 0.001), with sustained effects up to 6 months. MFWS assessments revealed that responder patients were 96.6% immediately after treatment, 76.6% one month, 48.3% after 3 months, and 28.3% at 6 months (p < 0.001). Additionally, there was a significant change in the frequency distribution of MFWS scores post-treatment (p < 0.001), with the majority of patients experiencing improvement in tissue depression. Maximum improvement was observed at 30- and 90-days post-treatment based on GAIS assessments. Patient and physician satisfaction, measured by VAS, remained stable over time, with fluctuations at 4 and 24 weeks after treatment (p < 0.001, Anova; p < 0.05, Wilcoxon). Throughout the entire follow-up duration of the patients enrolled in the study, no adverse effects related to the use of the product were observed.

Conclusion

 NEAUVIA Intense proved to be an effective solution for correcting NLF, providing significant and lasting improvements in tissue depression and aesthetic outcomes. The study underscores the necessity for continuous assessment in aesthetic medicine to align outcomes with evolving patient expectations and optimize long-term results. The findings contribute to the understanding of this specific hydrogel filler and highlight the broader context of injectable fillers in comprehensive facial aesthetic strategies.

Treatment-induced and Pre-existing Anti-peg Antibodies: Prevalence, Clinical Implications, and Future Perspectives

Polyethylene glycol (PEG) is a versatile polymer that is used in numerous pharmaceutical applications like the food industry, a wide range of disinfectants, cosmetics, and many commonly used household products. PEGylation is the term used to describe the covalent attachment of PEG molecules to nanocarriers, proteins and peptides, and it is used to prolong the circulation half-life of the PEGylated products. Consequently, PEGylation improves the efficacy of PEGylated therapeutics. However, after four decades of research and more than two decades of clinical applications, an unappealing side of PEGylation has emerged. PEG immunogenicity and antigenicity are remarkable challenges that confound the widespread clinical application of PEGylated therapeutics - even those under clinical trials - as anti-PEG antibodies (Abs) are commonly reported following the systemic administration of PEGylated therapeutics. Furthermore, pre-existing anti-PEG Abs have also been reported in healthy individuals who have never been treated with PEGylated therapeutics. The circulating anti-PEG Abs, both treatment-induced and pre-existing, selectively bind to PEG molecules of the administered PEGylated therapeutics inducing activation of the complement system, which results in remarkable clinical implications with varying severity. These include increased blood clearance of the administered PEGylated therapeutics through what is known as the accelerated blood clearance (ABC) phenomenon and initiation of serious adverse effects through complement activation-related pseudoallergic reactions (CARPA). Therefore, the US FDA industry guidelines have recommended the screening of anti-PEG Abs, in addition to Abs against PEGylated proteins, in the clinical trials of PEGylated protein therapeutics. In addition, strategies revoking the immunogenic response against PEGylated therapeutics without compromising their therapeutic efficacy are important for the further development of advanced PEGylated therapeutics and drug-delivery systems.

Band Engineering versus Catalysis: Enhancing the Self-Propulsion of Light-Powered MXene-Derived Metal-TiO2 Micromotors To Degrade Polymer Chains

Light-powered micro- and nanomotors based on photocatalytic semiconductors convert light into mechanical energy, allowing self-propulsion and various functions. Despite recent progress, the ongoing quest to enhance their speed remains crucial, as it holds the potential for further accelerating mass transfer-limited chemical reactions and physical processes. This study focuses on multilayered MXene-derived metal-TiO2 micromotors with different metal materials to investigate the impact of electronic properties of the metal-semiconductor junction, such as energy band bending and built-in electric field, on self-propulsion. By asymmetrically depositing Au or Ag layers on thermally annealed Ti3C2Tx MXene microparticles using sputtering, Janus structures are formed with Schottky junctions at the metal-semiconductor interface. Under UV light irradiation, Au-TiO2 micromotors show higher self-propulsion velocities due to the stronger built-in electric field, enabling efficient photogenerated charge carrier separation within the semiconductor and higher hole accumulation beneath the Au layer. On the contrary, in 0.1 wt % H2O2, Ag-TiO2 micromotors reach higher velocities both in the presence and absence of UV light irradiation, owing to the superior catalytic properties of Ag in H2O2 decomposition. Due to the widespread use of plastics and polymers, and the consequent occurrence of nano/microplastics and polymeric waste in water, Au-TiO2 micromotors were applied in water remediation to break down polyethylene glycol (PEG) chains, which were used as a model for polymeric pollutants in water. These findings reveal the interplay between electronic properties and catalytic activity in metal-semiconductor junctions, offering insights into the future design of powerful light-driven micro- and nanomotors with promising implications for water treatment and photocatalysis applications.

Ultra-high-performance liquid chromatography with tandem mass spectrometry method for cellular toxicity and pharmacokinetic study of PEG1K polymers

Polyethylene glycol (PEG) is one of the most commonly used polymers in drug delivery systems. The investigation of the pharmacokinetic behavior of PEG is important for revealing the toxicity and efficiency of PEG-related Nano-drug delivery systems. A high through-put and selective ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) method coupled with collision-induced dissociation (CID) in source technique was developed and validated to determine PEG1K polymers in cellular samples in this study. The countless precursor ions of PEG1K are dissociated in the source to generate numerous product ions which have different numbers of subunits. The transition of [M+H]+ precursor ions → product ions at m/z 177.1 (four subunits)→89.1 (two subunits) was selected to determine PEG1K due to its high sensitivity. The UHPLC-MS/MS method coupled with CID in the source showed good linearity over the range of 0.1-10 μg/mL. Intra-day and inter-day accuracies and precisions of the assay were all within ± 12.39%. The assay was successfully applied to a cellular pharmacokinetic study of PEG1K in human breast cancer cells. The cytotoxicity of PEG1K polymers was also studied and the results indicated that the cytotoxicity of PEG1K was not significant in the range of 5-1200 μg/mL.

Online Bipolar Dual Spray for the Charge State Reduction and Characterization of Complex Synthetic Polymers

Charge reduction mass spectrometry (CR/MS) hyphenated to liquid chromatography (LC) couples liquid-phase compound separation and mass spectral decompression to resolve and characterize multicomponent systems. LC/CR/MS has proven to be effective for complex mixture analysis, particularly synthetic polymers. A newer charge manipulation approach called bipolar dual spray has previously been demonstrated to reduce the observed charge state distribution of ammoniated polyethene glycol. In this approach, two electrospray emitters, in close proximity and of opposite polarity, fuse droplets from their electrospray plumes, which allows the subsequent chemistry. In this work, we investigate the ability of bipolar dual spray to reduce the charge of synthetic polyols, thereby simplifying complex mixture analysis and generating new compositional information only available through the coupling of charge reduction with LC/MS analysis. This work also represents the first demonstration of online charge reduction via dual spray. Polyethylene glycol (PEG) 7.2K subjected to LC/MS with dual spray reduced the average charge state from 8.2+ to 4.4+. LC/MS with dual spray was also applied to the characterization of an end-group-modified PEG 10K (i.e., aminated) containing several reaction impurities. This approach allowed for the identification of low-level starting material, tosylated PEG, and PEG mono(amine), where both LC/MS and direct infusion dual spray did not detect the impurities. Overall, the results demonstrated that bipolar dual spray can be incorporated into an LC/MS analysis and affords the ability to reduce the charge state distribution of PEG cations, decompress the m/z axis, lower spectra complexity, and enable/simplify data interpretation.

An investigation into the cytotoxic effects of microbubbles and their constituents on osteosarcoma and bone marrow stromal cells

BACKGROUND

Ultrasound-responsive microbubbles offer a means of achieving minimally invasive, localised drug delivery in applications including regenerative medicine. To facilitate their use, however, it is important to determine any cytotoxic effects they or their constituents may have. The aim of this study was to test the hypothesis that phospholipid-shelled microbubbles are non-toxic to human bone-derived cells at biologically-relevant concentrations.

METHODS

Microbubbles were fabricated using combinations of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-dibehenoyl-sn-glycero-3-phosphocholine (DBPC), polyoxyethylene(40) stearate (PEG40S) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene-glycol)-2000] (DSPE-PEG2000). Microbubble size and concentration were measured as a function of time and temperature by optical microscopy. Effects on MG63 osteosarcoma and human bone marrow stromal cells (BMSCs) were measured for up to 72 h by assay for viability, metabolic activity and proliferation.

RESULTS

DBPC:DSPE-PEG2000 microbubbles were significantly more stable than DSPC:PEG40S microbubbles under all conditions tested. Serum-containing medium had no detrimental effect on microbubble stability, but storage at 37 °C compared to at 4 °C reduced stability for both preparations, with almost complete dissolution of microbubbles at times ≥24 h. DSPC:PEG40S microbubbles had greater inhibitory effects on cell metabolism and growth than DBPC:DSPE-PEG2000 microbubbles, with PEG40S found to be the principle inhibitory component. These effects were only evident at high microbubble concentrations (≥20% (v/v)) or with prolonged culture (≥24 h). Increasing cell-microbubble contact by inversion culture in a custom-built device had no inhibitory effect on metabolism.

CONCLUSIONS

These data indicate that, over a broad range of concentrations and incubation times, DBPC:DSPE-PEG2000 and DSPC:PEG40S microbubbles have little effect on osteoblastic cell viability and growth, and that PEG40S is the principle inhibitory component in the formulations investigated.

A guide to modern methods for poly(thio)ether synthesis using Earth-abundant metals

Polyethers and polythioethers have a long and storied history dating back to the start of polymer science as a distinct field. As such, these materials have been utilized in a wide range of commercial applications and fundamental studies. The breadth of their material properties and the contexts in which they are applied is ultimately owed to their diverse monomer pre-cursors, epoxides and thiiranes, respectively. The facile polymerization of these monomers, both historically and contemporaneously, across academia and industry, has occurred through the use of Earth-abundant metals as catalysts and/or initiators. Despite this, polymerization methods for these monomers are underutilized compared to other monomer classes like cyclic olefins, vinyls, and (meth)acrylates. We feel a focused review that clearly outlines the benefits and shortcomings of extant synthetic methods for poly(thio)ethers along with their proposed mechanisms and quirks will help facilitate the utilization of these methods and by extension the unique polymer materials they create. Therefore, this Feature Article briefly describes the applications of poly(thio)ethers before discussing the feature-set of each poly(thio)ether synthetic method and qualitatively scoring them on relevant metrics (e.g., ease-of-use, molecular weight control, etc.) to help would-be poly(thio)ether-makers find an appropriate synthetic approach. The article is concluded with a look ahead at the future of poly(thio)ether synthesis with Earth-abundant metals.

Anti-PEG antibodies enriched in the protein corona of PEGylated nanocarriers impact the cell uptake

Poly(ethylene glycol) (PEG) is the gold standard used to reduce unspecific protein adsorption and prolong nanocarrier circulation time. However, this stealth effect could be counteracted by the increasing prevalence of anti-PEG antibodies in the bloodstream. Up to now, the presence of anti-PEG antibodies in the protein corona and their effect on cell uptake has not been investigated yet. Our results showed a high concentration and prevalence of anti-PEG antibodies in the German population. PEGylated nanocarriers exhibited a higher level of anti-PEG antibodies in the protein corona compared to non-PEGylated, which lead to higher uptake in macrophages. Consequently, the anti-PEG antibodies in the protein corona could mitigate the stealth effect of PEG, leading to accelerated blood clearance and unwanted side effects.

Production of Feline Universal Erythrocytes with Methoxy Polyethylene Glycol

Blood group mismatch in veterinary medicine is a significant problem in blood transfusion, sometimes leading to severe transfusion reactions and even patient death. Blood groups vary from species to species and there are three known blood groups in cats: A, B and AB. While A-type cats are most common, there is a shortage of feline B-type blood groups in cats. By using methoxy polyethylene glycol (mPEG) to protect antigenic epitopes on red blood cells (RBCs), we aimed to find the optimal conditions for the production of feline universal RBCs. The surfaces of feline A-type RBCs were treated with mPEG at various molecular weights and concentrations. Agglutination tests showed that the coating of feline A-type RBCs with mPEG of 20 kDa and 2 mM blocked hemagglutination to feline anti-A alloantibodies over 8 h. While no differences in RBC size and shape between intact and mPEG-treated RBCs were seen, coating RBCs with mPEG inhibited the binding of feline anti-A alloantibodies. Furthermore, the mPEG-treated RBCs did not cause spontaneous hemolysis or osmotic fragility, compared to control RBCs. According to a monocyte monolayer assay, mPEG treatment significantly reduced feline anti-A antibody-mediated phagocystosis of RBCs. These results confirm the potential of using activated mPEG on feline A-type RBC to create universal erythrocytes for transfusion to B-type cats.

Efficacy of Pegylated Hyaluronic Acid Filler Enriched with Calcium Hydroxyapatite: A 24-Week Post-Market, Observational, Prospective, Open-Label, Single-Center Study

Recently, thanks to the greater discovery of the mechanisms of facial aging, an alternative to invasive plastic surgery has found space with less invasive aesthetic procedures, also based on an increasingly pressing request. We are specifically referring to dermal filler injection into or under the skin which leads to immediate rejuvenation and aesthetic improvements. In this study, we wanted to analyze the results obtained through the use of NEAUVIA Organic Stimulate, particularly with regard to its effectiveness, which is a cross-linked polymeric hydrogel, containing stabilized sodium hyaluronate 26 mg/mL and calcium hydroxyapatite (1%), glycine and L-proline in buffer pyrogen-free water, in its main indication, namely, the temporary correction of congenital and acquired deficiencies of the soft tissues of the face by intradermal injection. Initially, 70 patients were enrolled, but 10 did not complete the study due to non-observance of the investigation rules, so they were excluded from the protocol. The collected data demonstrate an efficient mechanical effect of the pegylated polymeric acid matrix enriched with low concertation of calcium hydroxyapatite and in accordance with other evidence in vitro and in vivo, and the mechanical support of the interstitial connective space improves the homestays of the anatomical layer rebalancing the physiological activity of the dermis cells.

Tailoring thermoresponsiveness of biocompatible polyethers: copolymers of linear glycerol and ethyl glycidyl ether

Linear polyglycerol is known as a highly hydrophilic and biocompatible polymer that is currently considered for numerous medical applications. Derived from this well-known structure, the synthesis of highly biocompatible, thermoresponsive polyether copolymers via statistical anionic ring-opening copolymerization of ethyl glycidyl ether (EGE) and ethoxy ethyl glycidyl ether (EEGE) is described. Subsequent deprotection of the acetal groups of EEGE yields copolymers of linear glycerol (linG) and EGE, P(linG-co-EGE). These copolymers showed monomodal and narrow molecular weight distributions with dispersities Đ ≤ 1.07. The microstructure was investigated via in situ¹H NMR kinetics experiments, revealing reactivity ratios of r_EEGE = 1.787 ± 0.007 and r_EGE = 0.560 ± 0.002, showing a slightly favored incorporation of EEGE over EGE. Due to the deliberate incorporation of rather hydrophobic EGE units into the water soluble linPG, tunable thermoresponsive behavior is achieved with cloud point temperatures T_cp between 9.0-71.4 °C. Besides the commonly utilized method turbidimetry, temperature-dependent ¹H NMR measurements were used for more accurate and reproducible results. The change of the hydrodynamic radii r_H of the copolymers and their aggregates upon reaching T_cp was investigated via DOSY NMR spectroscopy. To explore possible biomedical applications, as an example, the cell viability and immunology of an exemplary P(linG-co-EGE) copolymer sample was investigated. Since both, cell viability and immunology are comparable to the gold standard PEG, the herein presented copolymers show high potential as biocompatible and thermoresponsive alternatives to PEG for biomedical applications.

One to one comparison of cell-free synthesized erythropoietin conjugates modified with linear polyglycerol and polyethylene glycol

With more than 20 Food and Drug Administration (FDA)-approved poly (ethylene glycol) (PEG) modified drugs on the market, PEG is the gold standard polymer in bioconjugation. The coupling improves stability, efficiency and can prolong blood circulation time of therapeutic proteins. Even though PEGylation is described as non-toxic and non-immunogenic, reports accumulate with data showing allergic reactions to PEG. Since PEG is not only applied in therapeutics, but can also be found in foods and cosmetics, anti-PEG-antibodies can occur even without a medical treatment. Hypersensitivity to PEG thereby can lead to a reduced drug efficiency, fast blood clearance and in rare cases anaphylactic reactions. Therefore, finding alternatives for PEG is crucial. In this study, we present linear polyglycerol (LPG) for bioconjugation as an alternative polymer to PEG. We report the conjugation of LPG and PEG by click-chemistry to the glycoprotein erythropoietin (EPO), synthesized in a eukaryotic cell-free protein synthesis system. Furthermore, the influence of the polymers on EPOs stability and activity on a growth hormone dependent cell-line was evaluated. The similar characteristics of both bioconjugates show that LPGylation can be a promising alternative to PEGylation.

Formulation and evaluation of the antimalarial N-89 as a transdermal drug candidate

The discovery of new effective and safe antimalarial drugs is mandatory. In this report, we formulate and evaluate transdermal (td) 1,2,6,7-tetraoxaspiro[7.11]nonadecane (N-89) using the Plasmodium berghei rodent malaria parasite in vivo model. The selected solvent for the ointment type of td N-89 was polyethylene glycol (PEG) [PEG400:PEG 4000 = 8:1 (v/w)]. We tested different application areas of 4, 6, and 8 cm² on the shaved backs of mice. Pharmacokinetic (PK) analysis of N-89 parameters after a single 4 cm² transdermal application revealed that the T_max was 2 h, the T_1/2 was 1.9 h, and the AUC was 1951.1 ng^.h/mL. More than 10 ng/mL of plasma concentration was maintained for 12 h. The ED₅₀ values for the 4, 6, and 8 cm² application areas in a 4-day suppressive test were 18.9, 25.1, and 26.8 mg/kg, respectively. We additionally tested the cure effect of td N-89 in mice at a dose of 60 mg/kg, twice daily for 4 days at 0.2% parasitemia. Parasites disappeared following day 7 post-treatment in all td N-89 treated groups. Mice were cured without any parasite recurrence or dermal irritation. In conclusion, this study determined for the first time the PK parameters and effect of a new ointment type of td N-89. This suggests that transdermal treatment with N-89 is an effective and safe alternative route for the treatment of malaria, especially in children.

Pioneer Use of Antimalarial Transdermal Combination Therapy in Rodent Malaria Model

We have previously reported 1,2,6,7-tetraoxaspiro [7.11]nonadecane (N-89) as a promising antimalarial compound. In this study, we evaluated the effect of transdermal therapy (tdt) of N-89 in combination (tdct) with other antimalarials as an application for children. We prepared ointment formulas containing N-89 plus another antimalarial drug, specifically, mefloquine, pyrimethamine, or chloroquine. In a 4-day suppressive test, the ED50 values for N-89 alone or combined with either mefloquine, pyrimethamine, or chloroquine were 18, 3, 0.1, and 3 mg/kg, respectively. Interaction assays revealed that N-89 combination therapy showed a synergistic effect with mefloquine and pyrimethamine, but chloroquine provoked an antagonistic effect. Antimalarial activity and cure effect were compared for single-drug application and combination therapy. Low doses of tdct N-89 (35 mg/kg) combined with mefloquine (4 mg/kg) or pyrimethamine (1 mg/kg) gave an antimalarial effect but not a cure effect. In contrast, with high doses of N-89 (60 mg/kg) combined with mefloquine (8 mg/kg) or pyrimethamine (1 mg/kg), parasites disappeared on day 4 of treatment, and mice were completely cured without any parasite recurrence. Our results indicated that transdermal N-89 with mefloquine and pyrimethamine provides a promising antimalarial form for application to children.

Investigation of anti-PEG antibody response to PEG-containing cosmetic products in mice

Polyethylene glycol (PEG), a polyether compound, is available in molecular weights from ∼300 g/mol to ∼10,000,000 g/mol. In the molecular weight range of ∼750 to ∼5000, PEG is commonly used in bioconjugation technology and nano-formulations to improve the circulation half-life of the formulations and increase their stability. In cosmetics, lower molecular weight PEG compounds such as PEG 60 or PEG 100 are widely used as emulsifiers and skin penetration enhancers. PEG polymers are generally recognized as biologically inert and non-immunogenic. However, it is recently reported that the "pre-existing" anti-PEG antibodies have been detected in high percentages of healthy individuals who have never received treatment with parenteral PEGylated formulations. To the best of our knowledge, we are the first to attempt to find an explanation for the source of pre-existing anti-PEG antibodies in healthy individuals. In a murine study, we demonstrated that topically applied PEG derivatives, present in two commercially available cosmetic products, could efficiently penetrate the stratum corneum and reach the systemic circulation. The skin penetration of PEG derivatives was further enhanced in injured or otherwise compromised skin. Daily application of cosmetic PEG derivatives primed the immune system, inducing anti-PEG IgM production. Anti-PEG IgM was detected by Day 14 in mice with normal skin, while anti-PEG IgM was detected as early as day 7 in mice with compromised skin. In addition, in mice with pre-induced circulating levels of anti-PEG IgM, topically applied PEG derivatives from cosmetic products appeared to bind to the pre-induced anti-PEG IgM, lowering blood levels. Current results indicate that PEG derivatives in cosmetic products may be an important contributor to the source of the "pre-existing" anti-PEG antibodies that have been detected in healthy individuals.

Alternative Excipients for Protein Stabilization in Protein Therapeutics: Overcoming the Limitations of Polysorbates

Given their safety and efficiency in protecting protein integrity, polysorbates (PSs) have been the most widely used excipients for the stabilization of protein therapeutics for years. In recent decades, however, there have been numerous reports about visible or sub-visible particles in PS-containing biotherapeutic products, which is a major quality concern for parenteral drugs. Alternative excipients that are safe for parenteral administration, efficient in protecting different protein drugs against various stress conditions, effective in protein stabilization in high-concentrated liquid formulations, stable under the storage conditions for the duration of the product's shelf-life, and compatible with other formulation components and the primary packaging are highly sought after. The aim of this paper is to review potential alternative excipients from different families, including surfactants, carbohydrate- and amino acid-based excipients, synthetic amphiphilic polymers, and ionic liquids that enable protein stabilization. For each category, important characteristics such as the ability to stabilize proteins against thermal and mechanical stresses, current knowledge related to the safety profile for parenteral administration, potential interactions with other formulation components, and primary packaging are debated. Based on the provided information and the detailed discussion thereof, this paper may pave the way for the identification or development of efficient excipients for biotherapeutic protein stabilization.

Suspect and non-targeted screening-based human biomonitoring identified 74 biomarkers of exposure in urine of Slovenian children

Human exposure to organic contaminants is widespread. Many of these contaminants show adverse health effects on human population. Human biomonitoring (HBM) follows the levels and the distribution of biomarkers of exposure (BoE), but it is usually done in a targeted manner. Suspect and non-targeted screening (SS/NTS) tend to find BoE in an agnostic way, without preselection of compounds, and include finding evidence of exposure to predicted, unpredicted known and unknown chemicals. This study describes the application of high-resolution mass spectrometry (HRMS)-based SS/NTS workflow for revealing organic contaminants in urine of a cohort of 200 children from Slovenia, aged 6-9 years. The children originated from two regions, urban and rural, and the latter were sampled in two time periods, summer and winter. We tentatively identified 74 BoE at the confidence levels of 2 and 3. These BoE belong to several classes of pharmaceuticals, personal care products, plasticizers and plastic related products, volatile organic compounds, nicotine, caffeine and pesticides. The risk of three pesticides, atrazine, amitraz and diazinon is of particular concern since their use was limited in the EU. Among BoE we tentatively identified compounds that have not yet been monitored in HBM schemes and demonstrate limited exposure data, such as bisphenol G, polyethylene glycols and their ethers. Furthermore, 7 compounds with unknown use and sources of exposure were tentatively identified, either indicating the entry of new chemicals into the market, or their metabolites and transformation products. Interestingly, several BoE showed location and time dependency. Globally, this study presents high-throughput approach to SS/NTS for HBM. The results shed a light on the exposure of Slovenian children and raise questions on potential adverse health effects of such mixtures on this vulnerable population.

Silicon Catalyzed C-O Bond Ring Closing Metathesis of Polyethers

The Lewis superacid bis(perchlorocatecholato)silane catalyzes C-O bond metathesis of alkyl ethers with an efficiency outperforming all earlier reported systems. Chemoselective ring contractions of macrocyclic crown ethers enable substrate-specific transformations, and an unprecedented ring-closing metathesis of polyethylene glycols allows polymer-selective degradation. Quantum chemical computations scrutinize a high Lewis acidity paired with a simultaneous low propensity for polydentate substrate binding as critical for successful catalysis. Based on these mechanistic insights, a second-generation class of silicon Lewis superacid with enhanced efficacy is identified and demonstrated.

mRNA-1273 but not BNT162b2 induces antibodies against polyethylene glycol (PEG) contained in mRNA-based vaccine formulations

Two messenger RNA (mRNA)-based vaccines are widely used globally to prevent coronavirus disease 2019 (COVID-19). Both vaccine formulations contain PEGylated lipids in their composition, in the form of polyethylene glycol [PEG] 2000 dimyristoyl glycerol for mRNA-1273, and 2 [(polyethylene glycol)-2000]-N,N-ditetradecylacetamide for BNT162b2. It is known that some PEGylated drugs and products for human use which contain PEG are capable of eliciting immune responses that lead to to detectable PEG-specific antibodies in serum. In this study, we determined if any of the components of mRNA-1273 or BNT162b2 formulations elicited PEG-specific antibody responses in serum by enzyme linked immunosorbent assay (ELISA). We detected an increase in the reactivity to mRNA vaccine formulations in mRNA-1273 but not BNT162b2 vaccinees' sera in a prime-boost dependent manner. Furthermore, we observed the same pattern of reactivity against irrelevant lipid nanoparticles from an influenza virus mRNA formulation and found that the reactivity of such antibodies correlated well with antibody levels against high and low molecular weight PEG. Using sera from participants selected based on the vaccine-associated side effects experienced after vaccination, including delayed onset, injection site or severe allergic reactions, we found no obvious association between PEG antibodies and adverse reactions. Overall, our data shows a differential induction of anti-PEG antibodies by mRNA-1273 and BNT162b2. The clinical relevance of PEG reactive antibodies induced by administration of the mRNA-1273 vaccine, and the potential interaction of these antibodies with other PEGylated drugs remains to be explored.

Polyethylene glycol (PEG): The nature, immunogenicity, and role in the hypersensitivity of PEGylated products

Polyethylene glycol (PEG) is a versatile polymer that is widely used as an additive in foods and cosmetics, and as a carrier in PEGylated therapeutics. Even though PEG is thought to be less immunogenic, or perhaps even non-immunogenic, with a variety of physicochemical properties, there is mounting evidence that PEG causes immunogenic responses when conjugated with other materials such as proteins and nanocarriers. Under these conditions, PEG with other materials can result in the production of anti-PEG antibodies after administration. The antibodies that are induced seem to have a deleterious impact on the therapeutic efficacy of subsequently administered PEGylated formulations. In addition, hypersensitivity to PEGylated formulations could be a significant barrier to the utility of PEGylated products. Several reports have linked the presence of anti-PEG antibodies to incidences of complement activation-related pseudoallergy (CARPA) following the administration of PEGylated formulations. The use of COVID-19 mRNA vaccines, which are composed mainly of PEGylated lipid nanoparticles (LNPs), has recently gained wide acceptance, although many cases of post-vaccination hypersensitivity have been documented. Therefore, our review focuses not only on the importance of PEGs and its great role in improving the therapeutic efficacy of various medications, but also on the hypersensitivity reactions attributed to the use of PEGylated products that include PEG-based mRNA COVID-19 vaccines.

Synthetic polymers in personal care and cosmetics products (PCCPs) as a source of microplastic (MP) pollution

Intentionally added MPs in PCCPs have created concerning threats to the environment. Therefore, this study aimed to screen synthetic polymers having MPs favoring chemical properties in PCCPs while estimating the theoretical emission into the environment and the level of awareness on the availability of MPs in PCCPs. A questionnaire survey was conducted via Google form using a complete random sampling method (n = 312). Next, a market survey was conducted and theoretical estimations were calculated for the products that recorded the highest MPs favoring polymers. Toothpaste products were identified as mostly used (95.8 %) and face cleanser (20.8 %) as least used. Of those MP ingredients, many chemical ingredients (11) were acrylate copolymers, and dimethicone polymers (5). A total of 21.4 trillion MP particles are released to the environment annually from considered four PCCPs. This study evidenced the availability of MP favoring chemicals in PCCPs in the Sri Lankan market that need further assessments.

Multiparametric cytotoxicity assessment: the effect of gold nanoparticle ligand functionalization on SKOV3 ovarian carcinoma cell death

Gold nanoparticles (AuNP) are promising anti-cancer agents because of their modifiable properties and high biocompatibility. This study used multiple parallel analyses to investigate the cytotoxic properties of 5 nm AuNP conjugated to four different ligands with distinct surface chemistry: polyethylene glycol (PEG), trimethylammonium bromide (TMAB), 4-dimethylaminopyridine (DMAP), and carboxyl (COOH). We used a range of biochemical and high-content microscopy methods to evaluate the metabolic function, oxidative stress, cell health, cell viability, and cell morphology in SKOV3 ovarian cancer cells. Each AuNP displayed a distinct cytotoxicity profile. All AuNP species assessed exhibited signs of dose-dependent cytotoxicity when morphology, clonogenic survival, lysosomal uptake, or cell number were measured as the marker of toxicity. All particles except for AuNP-COOH increased SKOV3 apoptosis. In contrast, AuNP-TMAB was the only particle that did not alter the metabolic function or induce significant signs of oxidative stress. These results demonstrate that AuNP surface chemistry impacts the magnitude and mechanism of SKOV3 cell death. Together, these findings reinforce the important role for multiparametric cytotoxicity characterization when considering the utility of novel particles and surface chemistries.

A Versatile Hydrophilic and Antifouling Coating Based on Dopamine Modified Four-Arm Polyethylene Glycol by One-Step Synthesis Method

A versatile hydrophilic and antifouling coating was designed and prepared based on catechol-modified four-arm polyethylene glycol. The dopamine (DA) molecules were grafted onto the end of the four-arm polyethylene glycol carboxyl (4A-PEG-COOH) through the amidation reaction, which was proven by ¹H NMR and FTIR analysis, assisting the strong adhesion of PEG on the surface of various types of materials, including metallic, inorganic, and polymeric materials. The reduction of the water contact angle and the bacteria-repellent and protein-repellent effects indicated that the coating had good hydrophilicity and antifouling performance. Raman spectroscopy analysis demonstrated the affinity between the polymeric surface and water, which further confirmed the hydrophilicity of the coating. Finally, in vitro cytotoxicity assay demonstrated good biocompatibility of the coating layer.

The preparation of phytosteryl succinyl sucrose esters and improvement of their water solubility and emulsifying properties

Phytosterols have gained much attention due to their outstanding cholesterol-reducing effect, while the insolubility in water limits their application. The aim of this study was to synthesize a novel hydrophilic phytosteryl derivatives-phytosteryl succinyl sucrose esters (PSSEs) and investigated their water solubility and emulsifying properties. PSSEs were synthesized by esterifying phytosterol hemisuccinates with sucrose through a mild chemical reaction. PSSEs were characterized by fourier transform infrared spectroscopy, mass spectroscopy, and nuclear magnetic resonance spectroscopy. The yield of PSSEs exceeded 84% in N,N-dimethylformamide for 36 h of reaction under the selected conditions: 100 mmol/L phytosteryl hemisuccinates, 150 mmol/L sucrose, 110 mmol/L 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochlide, 10 mmol/L 4-dimethylaminopyridine and 10 mmol/L p-toluenesulfonic acid. The water insolubility of phytosterols was overcome and the water solubility of PSSEs achieved 2.13 mg/mL. The emulsifying activity of PSSEs was 2.5 times that of phytosterols, reaching 0.95 mg/mL. PSSEs with better water solubility and emulsification properties could facilitate the widespread use of phytosterols in foods.

Physico-Chemical Characteristics and Posterolateral Fusion Performance of Biphasic Calcium Phosphate with Submicron Needle-Shaped Surface Topography Combined with a Novel Polymer Binder

A biphasic calcium phosphate with submicron needle-shaped surface topography combined with a novel polyethylene glycol/polylactic acid triblock copolymer binder (BCP-EP) was investigated in this study. This study aims to evaluate the composition, degradation mechanism and bioactivity of BCP-EP in vitro, and its in vivo performance as an autograft bone graft (ABG) extender in a rabbit Posterolateral Fusion (PLF) model. The characterization of BCP-EP and its in vitro degradation products showed that the binder hydrolyses rapidly into lactic acid, lactide oligomers and unaltered PEG (polyethylene glycol) without altering the BCP granules and their characteristic submicron needle-shaped surface topography. The bioactivity of BCP-EP after immersion in SBF revealed a progressive surface mineralization. In vivo, BCP-EP was assessed in a rabbit PLF model by radiography, manual palpation, histology and histomorphometry up to 12 weeks post-implantation. Twenty skeletally mature New Zealand (NZ) White Rabbits underwent single-level intertransverse process PLF surgery at L4/5 using (1) autologous bone graft (ABG) alone or (2) by mixing in a 1:1 ratio with BCP-EP (BCP-EP/ABG). After 3 days of implantation, histology showed the BCP granules were in direct contact with tissues and cells. After 12 weeks, material resorption and mature bone formation were observed, which resulted in solid fusion between the two transverse processes, following all assessment methods. BCP-EP/ABG showed comparable fusion rates with ABG at 12 weeks, and no graft migration or adverse reaction were noted at the implantation site nor in distant organs.

Toxicity of high-molecular-weight polyethylene glycols in Sprague Dawley rats

Polyethylene glycol (PEG) is present in a variety of products. Little is known regarding the accumulation of high-molecular-weight PEGs or the long-term effects resulting from PEG accumulation in certain tissues, especially the choroid plexus. We evaluated the toxicity of high-molecular-weight PEGs administered to Sprague Dawley rats. Groups of 12 rats per sex were administered subcutaneous injections of 20, 40, or 60 kDa PEG or intravenous injections of 60 kDa PEG at 100 mg PEG/kg body weight/injection once a week for 24 weeks. A significant decrease in triglycerides occurred in the 60 kDa PEG groups. PEG treatment led to a molecular-weight-related increase in PEG in plasma and a low level of PEG in cerebrospinal fluid. PEG was excreted in urine and feces, with a molecular-weight-related decrease in the urinary excretion. A higher prevalence of anti-PEG IgM was observed in PEG groups; anti-PEG IgG was not detected. PEG treatment produced a molecular-weight-related increase in vacuolation in the spleen, lymph nodes, lungs, and ovaries/testes, without an inflammatory response. Mast cell infiltration at the application site was noted in all PEG-treated groups. These data indicate that subcutaneous and intravenous exposure to high-molecular-weight PEGs produces tissue vacuolation without inflammation and anti-PEG IgM antibody responses.

Biological fate and interaction with cytochromes P450 of the nanocarrier material, D-α-tocopheryl polyethylene glycol 1000 succinate

d-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS, also known as vitamin E-TPGS) is a biodegradable amphiphilic polymer prepared by esterification of vitamin E with polyethylene glycol (PEG) 1000. It is approved by the US Food and Drug Administration (FDA) and has found wide application in nanocarrier drug delivery systems (NDDS). Fully characterizing the in vivo fate and pharmacokinetic behavior of TPGS is important to promote the further development of TPGS-based NDDS. However, to date, a bioassay for the simultaneous quantitation of TPGS and its metabolite, PEG1000, has not been reported. In the present study, we developed such an innovative bioassay and used it to investigate the pharmacokinetics, tissue distribution and excretion of TPGS and PEG1000 in rat after oral and intravenous dosing. In addition, we evaluated the interaction of TPGS with cytochromes P450 (CYP450s) in human liver microsomes. The results show that TPGS is poorly absorbed after oral administration with very low bioavailability and that, after intravenous administration, TPGS and PEG1000 are mainly distributed to the spleen, liver, lung and kidney before both being slowly eliminated in urine and feces as PEG1000. In vitro studies show the inhibition of human CYP450 enzymes by TPGS is limited to a weak inhibition of CYP3A4. Overall, our results provide a clear picture of the in vivo fate of TPGS which will be useful in evaluating the safety of TPGS-based NDDS in clinical use and in promoting their further development.

To PEGylate or not to PEGylate: Immunological properties of nanomedicine's most popular component, polyethylene glycol and its alternatives

Polyethylene glycol or PEG has a long history of use in medicine. Many conventional formulations utilize PEG as either an active ingredient or an excipient. PEG found its use in biotechnology therapeutics as a tool to slow down drug clearance and shield protein therapeutics from undesirable immunogenicity. Nanotechnology field applies PEG to create stealth drug carriers with prolonged circulation time and decreased recognition and clearance by the mononuclear phagocyte system (MPS). Most nanomedicines approved for clinical use and experimental nanotherapeutics contain PEG. Among the most recent successful examples are two mRNA-based COVID-19 vaccines that are delivered by PEGylated lipid nanoparticles. The breadth of PEG use in a wide variety of over the counter (OTC) medications as well as in drug products and vaccines stimulated research which uncovered that PEG is not as immunologically inert as it was initially expected. Herein, we review the current understanding of PEG's immunological properties and discuss them in the context of synthesis, biodistribution, safety, efficacy, and characterization of PEGylated nanomedicines. We also review the current knowledge about immunological compatibility of other polymers that are being actively investigated as PEG alternatives.

Overcoming hydrolytic degradation challenges in topical delivery: non-aqueous nano-emulsions

INTRODUCTION

Non-aqueous nano-emulsions (NANEs) are colloidal lipid-based dispersions with nano-sized droplets formed by mixing two immiscible phases, none of which happens to be an aqueous phase. Their ability to incorporate water and oxygen sensitive drugs without any susceptibility to degradation makes them the optimum dosage form for such candidates. In NANEs, polar liquids or polyols replace the aqueous phase while surfactants remain same as used in conventional emulsions. They are a part of the nano-emulsion family albeit with substantial difference in composition and application.

AREAS COVERED

The present review provides a brief insight into the strategies of loading water-sensitive drugs into NANEs. Further advancement in these anhydrous systems with the use of solid particulate surfactants in the form of Pickering emulsions is also discussed.

EXPERT OPINION

NANEs offer a unique platform for delivering water-sensitive drugs by loading them in anhydrous formulation. The biggest advantage of NANEs vis-à-vis the other nano-cargos is that they can also be prepared without using equipment-intensive techniques. However, the use of NANEs in drug delivery is quite limited. Looking at the small number of studies available in this direction, a need for further research in this field is required to explore this delivery system further.

Polyethylene Glycol Immunogenicity: Theoretical, Clinical, and Practical Aspects of Anti-Polyethylene Glycol Antibodies

Polyethylene glycol (PEG) is a flexible, hydrophilic simple polymer that is physically attached to peptides, proteins, nucleic acids, liposomes, and nanoparticles to reduce renal clearance, block antibody and protein binding sites, and enhance the half-life and efficacy of therapeutic molecules. Some naïve individuals have pre-existing antibodies that can bind to PEG, and some PEG-modified compounds induce additional antibodies against PEG, which can adversely impact drug efficacy and safety. Here we provide a framework to better understand PEG immunogenicity and how antibodies against PEG affect pegylated drug and nanoparticles. Analysis of published studies reveals rules for predicting accelerated blood clearance of pegylated medicine and therapeutic liposomes. Experimental studies of anti-PEG antibody binding to different forms, sizes, and immobilization states of PEG are also provided. The widespread use of SARS-CoV-2 RNA vaccines that incorporate PEG in lipid nanoparticles make understanding possible effects of anti-PEG antibodies on pegylated medicines even more critical.

Thermoresponsive Polymers Based on Tertiary Amine Moieties

Thermoresponsive polymers exhibiting unique reversible phase transition properties in aqueous solution in response to temperature stimuli have been extensively investigated. In the past two decades, thermoresponsive polymers based on tertiary amine moieties have achieved considerable progress and become an important family of thermoresponsive polymers, including tertiary amine functionalized poly((meth)acrylamide)s, poly((meth)acrylate)s, poly(styrene)s, poly(vinyl alcohol)s, and poly(ethylene oxide)s, which exhibit lower critical solution temperature and/or upper critical solution temperature in water or aliphatic alcohols. Their phase transition behavior can be modulated by the solution pH and CO₂ due to the protonation of tertiary amine moieties in acidic condition and deprotonation in alkaline condition and the charged ammonium bicarbonate formed by the tertiary amine moieties and CO₂ . The aim of this review is to summarize the recent progress in the thermoresponsive polymers based on tertiary amine moieties.

Overview of polyethylene glycol-based materials with a special focus on core-shell particles for drug delivery application

Polyethylene glycols (PEG) are water-soluble nonionic polymeric molecules. PEG and PEG-based materials are used for various important applications such as solvents, adhesives, adsorbents, drug delivery agents, tissue engineering scaffolds, etc. The coating of nanoparticles with PEG forms core-shell nanoparticles. The PEG-based core-shell nanoparticles are synthesized for the development of high-quality drug delivery systems. In the present review, we first explained the basics and various applications of PEGs and PEG-based composites materials and then concentrated on the PEG-based core-shell nanoparticles for biomedical applications specifically their use in drug delivery.

Polyethylene glycol acute and sub-lethal toxicity in neotropical Physalaemus cuvieri tadpoles (Anura, Leptodactylidae)

Although many polymers are known by their toxicity, we know nothing about the impact of polyethylene glycol (PEG) on anurofauna. Its presence in different products and disposal in aquatic environments turn assessments about its impact on amphibians an urgent matter. Accordingly, we tested the hypothesis that short-time exposure (72 h) of tadpoles belonging to the species Physalaemus cuvieri (Anura, Leptodactylidae) to PEG induces oxidative stress and neurotoxicity on them. We observed that polymer uptake in P. cuvieri occurred after exposure to 5 and 10 mg/L of PEG without inducing changes in their nitrite levels neither at the levels of substances reactive to thiobarbituric acid. However, hydrogen peroxide and reactive oxygen species production was higher in animals exposed to PEG, whose catalase and superoxide dismutase levels were not enough to counterbalance the production of these reactive species. Therefore, this finding suggests physiological changes altering REDOX homeostasis into oxidative stress. In addition, the increased activity of acetylcholinesterase and butyrylcholinesterase, and reduction in superficial neuromasts, confirmed PEG's neurotoxic potential. To the best of our knowledge, this is the first report on PEG's biological impact on a particular amphibian species. The study has broadened the understanding about ecotoxicological risks associated with water pollution by these polymers, as well as motivated further investigations on its impacts on amphibians' health and on the dynamics of their natural populations.