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Indoor Air Sep 2022Artificial fog is commonly employed in the entertainment industry and indoor household celebrations. The fog is generated from glycol-based solvents, which can also be...
Artificial fog is commonly employed in the entertainment industry and indoor household celebrations. The fog is generated from glycol-based solvents, which can also be found in e-cigarettes and personal care products. Although potential health impacts of glycol inhalation are frequently cited by studies of e-cigarette smoking, the dynamics and the chemical composition of glycol-based aerosols have never been studied systematically. The objective of this work is to investigate the impact of glycol-based aerosol on indoor air quality. Specifically, we targeted artificial fogs generated with common glycols, including propylene glycol (PG) and triethylene glycol (TEG). With the aid of a novel aerosol collecting and monitoring instrument setup, we obtained time-resolved aerosol profiles and their chemical compositions in an experimental room. Artificial fog has given rise to a significant amount of ultra-fine particulate matter, demonstrating its negative impact on indoor air quality. Additionally, we found a high concentration (9.75 mM) of formaldehyde and other carbonyls in fog machine fluids stored for months. These compounds are introduced to the indoor air upon artificial fog application. We propose that carbonyls have accumulated from the oxidative decomposition of glycols, initiated by OH radicals and singlet oxygens ( O ) and likely sustained by autooxidation. Oxidation of glycols by indoor oxidants has never been reported previously. Such chemical processes can represent an unrecognized source of toxic carbonyl compounds which is also applicable to other glycol-based solvents.
Topics: Aerosols; Air Pollutants; Air Pollution, Indoor; Electronic Nicotine Delivery Systems; Formaldehyde; Glycols; Oxidants; Particulate Matter; Propylene Glycol; Solvents; Weather
PubMed: 36168228
DOI: 10.1111/ina.13100 -
Journal of AOAC International Feb 2022Currently, there is no validated and available method internationally to determine the contents of nicotine and aerosolizing agents, namely glycerol and propylene...
A Simple Method to Simultaneously Determine the Level of Nicotine, Glycerol, Propylene Glycol, and Triacetin in Heated Tobacco Products by Gas Chromatography-Flame-Ionization Detection.
BACKGROUND
Currently, there is no validated and available method internationally to determine the contents of nicotine and aerosolizing agents, namely glycerol and propylene glycol, added onto the heatsticks for use in heated smoking devices.
OBJECTIVE
To determine the concentrations of nicotine, propylene glycol, glycerol and triacetin in heated tobacco products (HTPs) which is essential to understanding their health effects on smokers as well as secondhand smokers.
METHODS
A simple methodology was developed and validated to simultaneously determine nicotine, propylene glycol, glycerol, and triacetin concentrations present in heatsticks. The tobacco material was extracted with a mixture of methanol-acetonitrile (7 + 3, by volume) with 1,3-butanediol and n-heptadecane as internal standards and analyzed with gas chromatography with flame-ionization detection (GC-FID).
RESULTS
Good linearity was achieved over the following concentration ranges: 0.1-1.0 mg/mL for nicotine, 0.03-2.0 mg/mL for propylene glycol, 0.5-10.0 mg/mL for glycerol, and 0.1-4.0 mg/mL triacetin, with a coefficient of determination ≥0.995. The limits of detection and quantification were 0.0009 and 0.003 mg/mL for nicotine, 0.02 and 0.02 mg/mL for propylene glycol, 0.03 and 0.09 mg/mL for glycerol, and 0.005 and 0.02 mg/mL for triacetin, respectively. Good recoveries were obtained for nicotine at 89.8-102.0%, propylene glycol at 95.5-102.5%, glycerol at 95.2-102.6%, and triacetin at 90.6-103.1%.
CONCLUSION
This method provides an affordable and reliable technique for routine analysis of nicotine and aerosolizing chemicals present in HTPs which is necessary to assess their impact to public health.
HIGHLIGHTS
Many gaps remain in research on HTPs, in particular, country levels information on the content of the products are limited. This article contains information on a newly developed method to simultaneously determine nicotine, propylene glycol, glycerol and triacetin present in the tobacco material and butts of heatsticks for HTPs.
Topics: Chromatography, Gas; Glycerol; Nicotine; Propylene Glycol; Tobacco Products; Triacetin
PubMed: 34648035
DOI: 10.1093/jaoacint/qsab140 -
BioMed Research International 2022Plumbagin, a bioactive naphthoquinone, has demonstrated potent antitumor potential. However, plumbagin is a sparingly water-soluble compound; therefore, clinical...
Plumbagin, a bioactive naphthoquinone, has demonstrated potent antitumor potential. However, plumbagin is a sparingly water-soluble compound; therefore, clinical translation requires and will be facilitated by the development of a new pharmaceutical formulation. We have generated an oil-in-water nanoemulsion formulation of plumbagin using a low-energy spontaneous emulsification process with propylene glycol caprylate (Capryol 90) as an oil phase and Labrasol/Kolliphor RH40 as surfactant and cosurfactant excipients. Formulation studies using Capryol 90/Labrasol/Kolliphor RH40 components, based on pseudoternary diagram and analysis of particle size distribution and polydispersity determined by dynamic light scattering (DLS), identified an optimized composition of excipients for nanoparticle formulation. The nanoemulsion loaded with plumbagin as an active pharmaceutical ingredient had an average hydrodynamic diameter of 30.9 nm with narrow polydispersity. The nanoemulsion exhibited long-term stability, as well as good retention of particle size in simulated physiological environments. Furthermore, plumbagin-loaded nanoemulsion showed an augmented cytotoxicity against prostate cancer cells PTEN-P2 in comparison to free drug. In conclusion, we generated a formulation of plumbagin with high loading drug capacity, robust stability, and scalable production. Novel Capryol 90-based nanoemulsion formulation of plumbagin demonstrated antiproliferative activity against prostate cancer cells, warranting thus further pharmaceutical development.
Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Drug Carriers; Emulsions; Male; Mice; Nanoparticles; Naphthoquinones; Propylene Glycol; Prostatic Neoplasms
PubMed: 35047632
DOI: 10.1155/2022/3549061 -
International Journal of Environmental... Nov 2021To investigate passive vaping due to sub-ohm electronic cigarettes (e-cigs), aerosol number size distribution measurements (6 nm-10 µm) were performed during...
To investigate passive vaping due to sub-ohm electronic cigarettes (e-cigs), aerosol number size distribution measurements (6 nm-10 µm) were performed during volunteer-vaping sessions. E-liquids, with vegetable glycerin (VG) and propylene glycol (PG), with a VG/PG ratio of 50/50 (with nicotine) and 80/20 (without nicotine), were vaped with a double-coil, single aerosol exit hole at 25-80 W electric power, corresponding to 130-365 kW m heat fluxes and with an octa-coil, four aerosol exit holes atomizers, at 50-150 W electric power, corresponding to 133-398 kW m heat fluxes. At the lowest heat flux, lower particle number concentrations (N) were observed for the nicotine-liquid than for the nicotine-free liquid, also due to its higher content of PG, more volatile than VG. For the octa-coil atomizer, at 265 and 398 kW m, N decreased below the first-generation e-cig, whereas volume concentrations greatly increased, due to the formation of super micron droplets. Higher volume concentrations were observed for the 80/20 VG/PG liquid, because of VG vaporization and of its decomposition products, greater than for PG. For the double coil atomizer, increasing the electric power from 40 W (208 kW m) to 80 W (365 kW m) possibly led to a critical heat flow condition, causing a reduction of the number concentrations for the VG/PG 50/50 liquid, an increase for the 80/20 VG/PG liquid and a decrease of the volume concentrations for both of them. Coherently, the main mode was at about 0.1 µm on both metrics for both liquids. For the other tests, two main modes (1 and 2 µm) were observed in the volume size distributions, the latter becoming wider at 100 and 150 W (265 and 398 kW m), suggesting the increased emission of light condensable decomposition products. The lower aerosol emissions observed at 150 W than at 100 W suggest the formation of gas-phase decomposition products. The observation of low-count high-volume aerosols addresses the relevance of the volume metric upon measuring the second-hand concentration of the aerosols released by sub-ohm e-cigarettes.
Topics: Aerosols; Electronic Nicotine Delivery Systems; Humans; Nicotine; Propylene Glycol; Vaping
PubMed: 34770123
DOI: 10.3390/ijerph182111606 -
Dental Materials : Official Publication... Feb 2016To determine the effects of various monomers on conversion and cytocompatibility of dental composites and to improve these properties without detrimentally affecting...
OBJECTIVES
To determine the effects of various monomers on conversion and cytocompatibility of dental composites and to improve these properties without detrimentally affecting mechanical properties, depth of cure and shrinkage.
METHODS
Composites containing urethane dimethacrylate (UDMA) or bisphenol A glycidyl methacrylate (Bis-GMA) with poly(propylene glycol) dimethacrylate (PPGDMA) or triethylene glycol dimethacrylate (TEGDMA) were characterized using the following techniques: conversion (FTIR at 1 and 4mm depths), depth of cure (BS EN ISO 4049:2009 and FTIR), shrinkage (BS EN ISO 17304:2013 and FTIR), strength and modulus (biaxial flexural test) and water sorption. Cytocompatibility of composites and their liquid phase components was assessed using three assays (resazurin, WST-8 and MTS).
RESULTS
UDMA significantly improved conversion, BFS and depth of cure compared to Bis-GMA, without increasing shrinkage. UDMA was cytotoxic at lower concentrations than Bis-GMA, but extracts of Bis-GMA-containing composites were less cytocompatible than of those containing UDMA. PPGDMA improved conversion and depth of cure compared to TEGDMA, without detrimentally affecting shrinkage. TEGDMA was shown by all assays to be highly toxic. Resazurin, but not WST-8 and MTS, suggested that PPGDMA exhibited improved cytocompatibility compared to TEGDMA.
SIGNIFICANCE
The use of UDMA and PPGDMA results in composites with excellent conversion, depth of cure and mechanical properties, without increasing shrinkage. Composites containing UDMA appear to be slightly more cytocompatible than those containing Bis-GMA. These monomers may therefore improve the material properties of dental restorations, particularly bulk fill materials. The effect of diluent monomer on cytocompatibility requires further investigation.
Topics: Biocompatible Materials; Bisphenol A-Glycidyl Methacrylate; Composite Resins; Elastic Modulus; Light-Curing of Dental Adhesives; Materials Testing; Methacrylates; Phase Transition; Polyethylene Glycols; Polymerization; Polymethacrylic Acids; Polyurethanes; Propylene Glycol; Surface Properties; Tensile Strength
PubMed: 26764174
DOI: 10.1016/j.dental.2015.11.017 -
Inhalation Toxicology Jan 2021The use of vaping pens for inhalation of cannabinoid derived products is rising and has become a popular alternative to smoking combustible products. For efficient...
The use of vaping pens for inhalation of cannabinoid derived products is rising and has become a popular alternative to smoking combustible products. For efficient product delivery, additives are sometimes added and vaping pens often may include compounds like Phytol or Propylene Glycol as thinning agents. This study aimed at comparing Phytol and Propylene Glycol with respect to potential toxicity and safe use in vaping products. Male and female Sprague Dawley rats were exposed to 5 mg/L of Phytol or Propylene Glycol for up to 6 hours over up to 14 days and monitored for clinical signs and changes in body weight. Gross necropsy and histopathology of respiratory tissue was performed to assess potential adverse effects. Phytol exposed animals expressed severe clinical signs, body weight loss and mortality after one or two exposure days, leading to termination of all dose groups for this compound. Lung weights were increased and respiratory tissue was severely affected, demonstrating dose-responsive tissue degeneration, necrosis, edema, hemorrhage and inflammation. Propylene Glycol exposed animals did not show any adverse reactions after 14 days of high dose exposure. For Phytol, a low observed adverse effect level (LOAEL) was determined at ≤109.0/10.9 mg/kg/day presented/deposited dose and therefore its use as excipient in vaping product is not recommend; a safe exposure range was not established for Phytol. Propylene Glycol, in contrast, is considered safe with a no observed adverse effect level (NOAEL) at 1151.7/115.2 mg/kg/day presented/deposited dose in rats.
Topics: Animals; Female; Inhalation Exposure; Lung Injury; Male; Phytol; Propylene Glycol; Rats; Rats, Sprague-Dawley
PubMed: 33441006
DOI: 10.1080/08958378.2020.1867260 -
Biomacromolecules Oct 2023In this work, isocyanate-free formulations for poly(propylene glycol) polyurethane elastomers are studied. These formulations are based on poly(propylene glycol)...
In this work, isocyanate-free formulations for poly(propylene glycol) polyurethane elastomers are studied. These formulations are based on poly(propylene glycol) end-capped by CO-sourced cyclic carbonate (bisCC PPG) macromonomers able to react with amines leading to poly(hydroxyurethane)s. In order to obtain covalent networks, two curing approaches are studied. First, the direct thermally activated cross-linking of bisCC PPG with a mixture of various aliphatic or aromatic diamines and a triamine is investigated, and in particular the nature of the diamine on the mechanical properties. In the second approach, UV-activated formulations are developed by reacting bisCC PPG with allylamine followed by the addition of a trithiol by photoactivated thiol-ene reaction. The swelling tests show that both systems provide highly cross-linked polymer networks and complementary characterizations highlighted excellent mechanical properties. Thanks to the fast curing and adapted viscosity of the developed photoactive formulation, the latter was found suitable for use as a photoresin for 3D printing as demonstrated by printing a vaginal ring by a nozzle-based photoprinter.
Topics: Elastomers; Propylene Glycol; Polymers; Polyurethanes; Isocyanates
PubMed: 36113039
DOI: 10.1021/acs.biomac.2c00860 -
International Journal of Hygiene and... Apr 2018Electronic cigarette (e-cigarette) conventions bring hundreds to thousands of e-cigarette users together socially regularly across the world. E-cigarette secondhand...
BACKGROUND
Electronic cigarette (e-cigarette) conventions bring hundreds to thousands of e-cigarette users together socially regularly across the world. E-cigarette secondhand exposures to chemicals in this environment, likely the public setting with the highest concentration of e-cigarette secondhand aerosol, have not been characterized.
METHODS
Air sampling for formaldehyde, acetaldehyde, acrolein, nicotine, and propylene glycol was conducted at three e-cigarette conventions and one smaller event from April 2016 to March 2017 in three states in the Southeastern United States. Volunteers attended the events as members of the public and wore backpacks containing air sampling pumps. Control sampling was conducted when venues were crowded for non-e-cigarette events. Additional control sampling was conducted in two venues when they were empty.
RESULTS
Formaldehyde and acetaldehyde concentrations during e-cigarette events were comparable to background concentrations. The median formaldehyde concentrations during events, crowded control events, and empty control events were 12.0, 10.5, and 12.5 μg/m, respectively. The median acetaldehyde concentrations during events, crowded control events, and empty control events were 9.7, 15.5, and 3.5 μg/m, respectively. Propylene glycol and nicotine were not detected during control sampling. The median nicotine concentration during events was 1.1 μg/m. The median propylene glycol concentration during events was 305.5 μg/m.
CONCLUSION
Results indicate e-cigarette secondhand exposures are sources of elevated nicotine and propylene glycol exposures. Secondhand exposures to e-cigarettes did not contain consistently elevated concentrations of formaldehyde or acetaldehyde. Additional research is needed to characterize exposures via inhalation to propylene glycol at concentrations measured in this study.
Topics: Acetaldehyde; Aerosols; Air Pollutants; Air Pollution, Indoor; Electronic Nicotine Delivery Systems; Environmental Exposure; Environmental Monitoring; Formaldehyde; Humans; Nicotine; Propylene Glycol; Volatile Organic Compounds
PubMed: 29477829
DOI: 10.1016/j.ijheh.2018.02.003 -
Journal of Endodontics Mar 2016The aim of this study was to evaluate the physical, chemical, and biological properties of mineral trioxide aggregate (MTA) mixed with 80% distilled water and 20%...
INTRODUCTION
The aim of this study was to evaluate the physical, chemical, and biological properties of mineral trioxide aggregate (MTA) mixed with 80% distilled water and 20% propylene glycol (PG) compared with MTA mixed with distilled water only.
METHODS
Flowability, film thickness, and solubility were analyzed according to American National Standards Institute/American Dental Association specification 57/2000. Initial and final setting times were assessed according to American Society for Testing and Materials specification C266/08. Porosity was assessed by using mercury intrusion porosimetry after 1 and 28 days of hydration, and the pH and calcium ion release were assessed after 3, 24, 72, and 168 hours. For the tissue reaction, the cements were implanted in 24 albino rats (2 groups, n = 12). An analysis of the inflammatory infiltrate was performed after 15, 30, and 60 days.
RESULTS
MTA + PG exhibited lower film thickness and higher final setting time. No differences were verified for flowability (P > .05). MTA + PG showed high porosity at 1 day of hydration (P < .05). All the test cements demonstrated an alkaline pH. Microscopic analysis of the specimens revealed neoformation of connective tissue in contact with the cements.
CONCLUSIONS
The introduction of PG as a mixing vehicle alters the physical and chemical properties of MTA and is biologically acceptable.
Topics: Aluminum Compounds; Animals; Calcium Compounds; Connective Tissue; Drug Combinations; Implants, Experimental; Male; Materials Testing; Oxides; Porosity; Propylene Glycol; Rats; Root Canal Filling Materials; Silicates; Subcutaneous Tissue
PubMed: 26706789
DOI: 10.1016/j.joen.2015.10.014 -
Magnetic Resonance in Chemistry : MRC Nov 2016The variability of the electronic cigarette liquids (e-liquid) composition has the potential to influence not only the amount of nicotine delivered to the user, but also...
The variability of the electronic cigarette liquids (e-liquid) composition has the potential to influence not only the amount of nicotine delivered to the user, but also the type and amount of generated byproducts and subsequent health risks. For this reason, it is important to characterize all of the chemical components of e-liquids. We report the development and application of a single H NMR analysis method to identify and quantify the most abundant chemical components (nicotine, glycerol, 1,2-propylene glycol, and water) likely to be present as their influence on the composition of inhaled vapor is not know. For H NMR, the solvent has to dissolve the e-liquids at a concentration sufficient to readily determine the concentration of nicotine present, and the solvent and internal standard cannot possess exchangeable protons which would interfere with determining the concentrations of the analytes of interest. To fulfill these requirements, perdeuterated -dimethylformamide (DMF-) was selected as the solvent, with 1,2,4,5-tetrachloro-3-nitrobenzene as the internal standard. Nicotine concentrations from 58 different e-liquids obtained using H NMR were found to agree with the results from GC-MS analysis. Generally, the amount of nicotine present was close to that claimed by the manufacturer. In some cases, the proportions of 1,2-propylene glycol, glycerol, and water varied significantly between flavors within a brand and within flavors depending on the nicotine content. In one case, 1,2-propylene glycol was identified where the manufacturer had stated none should be present.
Topics: Electronic Nicotine Delivery Systems; Glycerol; Nicotine; Propylene Glycol; Proton Magnetic Resonance Spectroscopy; Solvents; Water
PubMed: 27495876
DOI: 10.1002/mrc.4498