-
Spectrochimica Acta. Part A, Molecular... Jan 2023Raman spectra of ethylene glycol (EG) and 1,3-propylene glycol (1,3-PG) aqueous solutions with the diol content from 10 to 90 mol% were measured. The diol content...
Raman spectra of ethylene glycol (EG) and 1,3-propylene glycol (1,3-PG) aqueous solutions with the diol content from 10 to 90 mol% were measured. The diol content weakly influences the EG and 1,3-PG Raman bands in the spectra of the solutions in the region 250-1800 cm. This fact means that the conformational compositions of both the diols do not change significantly with dissolving in water. The intensity of the OH stretching band with respect to the diol bands intensities is the linear function of the ratio of the mole contents of water and the diol in the solutions. The spectral region 2800-3800 cm can be used to evaluate the chemical composition of these binary solutions. DFT modeling of the Raman spectra of EG molecule in water shell confirms the prevalence of the gauche-conformation of EG in the aqueous solutions.
Topics: Ethylene Glycol; Spectrum Analysis, Raman; Water; Molecular Conformation; Propylene Glycol; Solutions
PubMed: 36209716
DOI: 10.1016/j.saa.2022.121927 -
Materials (Basel, Switzerland) May 2023Research on the use of biomass resources for the generation of energy and chemical compounds is of great interest worldwide. The development and growth of the biodiesel... (Review)
Review
Research on the use of biomass resources for the generation of energy and chemical compounds is of great interest worldwide. The development and growth of the biodiesel industry has led to a parallel market for the supply of glycerol, its main by-product. Its wide availability and relatively low cost as a raw material make glycerol a basic component for obtaining various chemical products and allows for the development of a biorefinery around biodiesel plants, through the technological integration of different production processes. This work proposes a review of one of the reactions of interest in the biorefinery environment: the hydrogenolysis of glycerol to 1,2-propylene glycol. The article reviews more than 300 references, covering literature from about 20 years, focusing on the heterogeneous catalysts used for the production of glycol. In this sense, from about 175 catalysts, between bulk and supported ones, were revised and discussed critically, based on noble metals, such as Ru, Pt, Pd, and non-noble metals as Cu, Ni, Co, both in liquid (2-10 MPa, 120-260 °C) and vapor phase (0.1 MPa, 200-300 °C). Then, the effect of the main operational and decision variables, such as temperature, pressure, catalyst/glycerol mass ratio, space velocity, and H flow, are discussed, depending on the reactors employed. Finally, the formulation of several kinetic models and stability studies are presented, discussing the main deactivation mechanisms of the catalytic systems such as coking, leaching, and sintering, and the presence of impurities in the glycerol feed. It is expected that this work will serve as a tool for the development of more efficient catalytic materials and processes towards the future projection of glycerol biorefineries.
PubMed: 37176434
DOI: 10.3390/ma16093551 -
Acta Otorhinolaryngologica Italica :... Oct 2021The aim of this study was to investigate the inhibitory effect of different doses of sodium-2-mercaptoethanesulphonate (MESNA) and 5-fluorouracil on cholesteatoma...
OBJECTIVE
The aim of this study was to investigate the inhibitory effect of different doses of sodium-2-mercaptoethanesulphonate (MESNA) and 5-fluorouracil on cholesteatoma formation.
METHODS
Fifty-six Wistar albino male rats were divided into seven groups with eight rats in each. On the first, eighth and fifteenth days, 0.2 ml of saline was administered to the group 1 (control group), and propylene glycol to induce cholesteatoma the other groups. On the 22 day of the study, 0.2 ml saline was given to Group 1 and Group 2. Groups 3 to 7 were treated with 0.2 ml 100% MESNA, 0.2 ml 50% MESNA, 0.2 ml 20% MESNA, 0.2 ml 5-fluorouracil and 0.1 ml 100% MESNA plus 0.1 ml 5-fluorouracil, respectively, with all applications performed by intratympanic injection.
RESULTS
Significant differences were found between Group 1 and all other groups except Group 3. Significant differences were also found between Group 3 and Groups 2, 5 and 6 (P < 0.05).
CONCLUSIONS
According to the results of this study, experimental cholesteatoma induced with propylene glycol may be inhibited by MESNA at 100% concentration.
Topics: Animals; Cholesteatoma, Middle Ear; Fluorouracil; Humans; Mesna; Propylene Glycols; Rats; Rats, Wistar
PubMed: 34734585
DOI: 10.14639/0392-100X-N1392 -
Dermatitis : Contact, Atopic,...Both active and inactive ingredients in topical ophthalmic agents may cause allergic contact dermatitis. Here, we examined ingredients in prescription topical ophthalmic...
BACKGROUND/OBJECTIVE
Both active and inactive ingredients in topical ophthalmic agents may cause allergic contact dermatitis. Here, we examined ingredients in prescription topical ophthalmic medications available in the United States.
METHODS
A comprehensive list of topical ophthalmic medications was generated using AccessPharmacy. Categories included antiglaucoma, antibiotic, antibiotic/corticosteroid, corticosteroid, antiviral, antifungal, mydriatic, and miotic agents. For each formulation, ingredients were investigated using the National Institutes of Health US National Library of Medicine database and/or manufacturer websites. Counts and proportions were calculated for inactive ingredients, including those in the American Contact Dermatitis Society (ACDS) Core 90 Allergen Series.
RESULTS
Two hundred sixty-four unique prescription ophthalmic medications met the inclusion criteria. The most common ACDS Core 90 allergen/cross-reactor inactive ingredient was benzalkonium chloride (68.1%, 180/264), followed by sorbates (11.7%, 31/264), parabens (6.8%, 18/264), sodium metabisulfite (3.8%, 10/264), propylene glycol (3.0%, 8/264), and lanolin (3.0%, 8/264). Approximately 21% (20.8%, 55/264) of products had no ACDS Core 90 allergens/cross-reactor inactive ingredients. The most common ACDS Core 90 allergen/cross-reactor active ingredients were aminoglycoside antibiotics, bacitracin/polymyxin B, and corticosteroids. Important non-ACDS Core 90 allergens included inactive ingredients, such as EDTA 28.0% and thimerosal 2.7%, as well as active ingredients, especially β-blockers.
CONCLUSIONS
Benzalkonium chloride, sodium metabisulfite, propylene glycol, and lanolin were common inactive ingredient allergens. Most ophthalmic categories had low allergen formulations available for patients with contact allergy.
Topics: Allergens; Dermatitis, Allergic Contact; Drug Hypersensitivity; Humans; Lanolin; Ophthalmology; Patch Tests; Prescriptions; Propylene Glycol; Sulfites; United States
PubMed: 34115664
DOI: 10.1097/DER.0000000000000751 -
Molecules (Basel, Switzerland) Dec 2023Binary ethosome vesicles have been developed as flexible lipid vesicles for the enhanced physicochemical stability and skin delivery of drugs. This work aimed to prepare...
Binary ethosome vesicles have been developed as flexible lipid vesicles for the enhanced physicochemical stability and skin delivery of drugs. This work aimed to prepare phloretin-loaded propylene glycol ethosomes (PHL-PGEs) to improve their stability, skin permeability and antioxidant activity. PHL-PGEs were prepared via the ethanol injection method and optimized using different weight ratios of ethanol to propylene glycol (PG). When the ethanol/PG mass ratio changed from 10:0 to 0:10, the encapsulation efficiency and stability of ethosomes increased. At a PHL concentration of 1mg/mL, the EE% was 89.42 ± 2.42 and the DL% was 4.21 ± 0.04, which exhibited their highest values. The encapsulation of the PHL in the PHL-PGEs was strengthened via XRD analysis and FTIR analysis. The results of the in vitro percutaneous permeability test demonstrated that the combined use of ethanol and PG exhibited a notable enhancement in skin permeability, and the skin retention of PHL-PGEs was 1.06 times that of PHL-ethosomes (PHL-Es) and 2.24 times that of the PHL solution. An in vitro antioxidant activity study indicated that solubility and antioxidant activity was potentiated via the nanoencapsulation of phloretin. Therefore, these results confirm the potential of this nanocarrier to enhance physicochemical stability, skin permeability and antioxidant activity.
Topics: Antioxidants; Ethanol; Permeability; Phloretin; Propylene Glycol
PubMed: 38202649
DOI: 10.3390/molecules29010066 -
Inhalation Toxicology May 2020E-cigarettes are electronic devices containing a liquid that usually consists of a mixture of glycerol, propylene glycol and nicotine, with or without flavorings, in...
E-cigarettes are electronic devices containing a liquid that usually consists of a mixture of glycerol, propylene glycol and nicotine, with or without flavorings, in various concentrations. A vapor or aerosol is produced, and inhaled from the user, when this liquid is heated by a heating coil. This work examines the impact of three parameters (e-liquid composition, nicotine content and air flow) on the transfer of metals' from the heating coils to the e-liquids. A distillation unit was used, where 20ml of an e-liquid were boiled with two commercial heating elements. Four e-liquids: 100% Propylene Glycol, 100% Glycerol, 50/50% Propylene Glycol/Glycerol, 33.3/33.3/33.3% Propylene Glycol/Glycerol/Water, three nicotine contents: 0, 0.4 and 0.8% per volume and three air flows: 0, 0.5 and 1.0 L/min, were used. The liquids were analyzed by Total Reflection X-Ray Fluorescence spectrometry to determine the final content of metals. Five metals, Fe, Ni, Cu, Zn, and Pb, were found to be transferred from the heating coils to the e-liquids. The transfer of those metals increases with air flow and nicotine concentration, while e-liquid composition also has a significant impact. Glycerol enhances the transfer of metals compared to propylene glycol and their mixtures. The boiling temperature of the e-liquids increases significantly the transfer of metals in the e-liquids. There is a transfer of metals from the heating coils to the e-liquids. This transfer depends on the e-liquid composition and on the boiling temperature.
Topics: Electronic Nicotine Delivery Systems; Glycerol; Hot Temperature; Metals, Heavy; Nicotine; Propylene Glycol; Water
PubMed: 32538207
DOI: 10.1080/08958378.2020.1776801 -
Epigenetics 2022Increasing use of non-combusted forms of nicotine such as e-cigarettes poses important public health questions regarding their specific risks relative to combusted...
Increasing use of non-combusted forms of nicotine such as e-cigarettes poses important public health questions regarding their specific risks relative to combusted tobacco products such as cigarettes. To fully delineate these risks, improved biomarkers that can distinguish between these forms of nicotine use are needed. Prior work has suggested that methylation status at cg05575921 may serve as a specific biomarker of combusted tobacco smoke exposure. We hypothesized combining this epigenetic biomarker with conventional metabolite assays could classify the type of nicotine product consumption. Therefore, we determined DNA methylation and serum cotinine values in samples from 112 smokers, 35 e-cigarette users, 19 smokeless tobacco users, and 269 controls, and performed mass spectroscopy analyses of urine samples from all nicotine users and 22 verified controls to determine urinary levels of putatively nicotine product-specific substances; propylene glycol, 2-cyanoethylmercapturic acid (CEMA), and anabasine. 1) Cigarette smoking was associated with a dose dependent demethylation of cg05575921 and increased urinary CEMA and anabasine levels, 2) e-cigarette use did not demethylate cg05575921, 3) smokeless tobacco use also did not demethylate cg05575921 but was positively associated with anabasine levels 4) CEMA and cg05575921 levels were highly correlated and 5) propylene glycol levels did not reliably distinguish use groups. Cg05575921 assessments distinguish exposure to tobacco smoke from smokeless sources of nicotine including e-cigarettes and smokeless tobacco, neither of which are associated with cg05575921 demethylation. A combination of methylomic and metabolite profiling may allow for accurate classification use status of a variety of nicotine containing products.
Topics: DNA Methylation; Electronic Nicotine Delivery Systems; Nicotine; Nicotiana; Tobacco Products; Vaping
PubMed: 33588690
DOI: 10.1080/15592294.2021.1890875 -
Current Allergy and Asthma Reports Mar 2021This article aims to summarize some recent trends in occupational allergic contact dermatitis (ACD), including dermatitis related to pandemic-level personal protective... (Review)
Review
PURPOSE OF REVIEW
This article aims to summarize some recent trends in occupational allergic contact dermatitis (ACD), including dermatitis related to pandemic-level personal protective equipment in healthcare workers, hazards patients may experience when working from home, and occupational perspectives on the recent American Contact Dermatitis Society (ACDS) allergens of the year and ACDS Core Allergen Series updates.
RECENT FINDINGS
Recent ACDS Allergens of the Year may be particularly relevant to healthcare workers, including isobornyl acrylate, which is present in glucose sensors and propylene glycol present in hand cleansers and disinfectants. Lavender, limonene, and linalool, all of which are new additions to the ACDS Core Allergen Series, have been reported as causes for occupational ACD in massage therapists and aromatherapists. Isothiazolinone allergy continues to rise in both consumer and occupational settings. Finally, the COVID-19 pandemic has resulted in a wave of occupational ACD in healthcare workers to personal protective equipment, and revealed new potential allergens for individuals working from home. Occupational allergic contact dermatitis continues to exert a significant occupational disease burden. Remaining aware of the current trends in allergens may allow for earlier recognition, diagnosis, and treatment, subsequently helping our patients to work in healthier and safer environments.
Topics: Acrylates; Acyclic Monoterpenes; Allergens; Allergy and Immunology; COVID-19; Camphanes; Dermatitis, Allergic Contact; Dermatitis, Occupational; Dermatology; Health Personnel; Humans; Lavandula; Limonene; Pandemics; Patch Tests; Propylene Glycol; Societies, Medical; United States
PubMed: 33779825
DOI: 10.1007/s11882-021-01000-3 -
Current Drug Delivery 2024Nicotine is a fat-soluble substance that is easily absorbed through the skin and mucosal tissues of the human body. However, its properties, such as light exposure, heat...
BACKGROUND
Nicotine is a fat-soluble substance that is easily absorbed through the skin and mucosal tissues of the human body. However, its properties, such as light exposure, heat decomposition, and volatilization, restrict its development and application in external preparations.
OBJECTIVE
This study focused on the preparation of stable nicotine-encapsulated ethosomes.
METHODS
During their preparation, two water-phase miscible osmotic promoters, ethanol and propylene glycol (PG), were added to obtain a stable transdermal delivery system. Skin nicotine delivery was enhanced through the synergistic action of osmotic promoters and phosphatidylcholine in binary ethosomes. Various characteristics of the binary ethosomes were measured, including the vesicle size, particle size distribution, and zeta potential. In order to optimize the ratio of ethanol and PG, the skin permeability test was performed on mice in vitro in a Franz diffusion cell to compare cumulative skin permeabilities. The penetration depth and fluorescence intensity of rhodamine-B-entrapped vesicles in isolated mouse skin samples were observed using laser confocal scanning microscopy.
RESULTS
When ethanol:PG was used in a ratio of 5:5 (w/w), binary ethosomes were found to be the most stable, had the highest encapsulation rate (86.13 ± 1.40), smallest particle size (106.0 ± 11.0) nm, maximum transdermal depth (180 μm), and maximum fluorescence intensity (160 AU). Nicotineencapsulated ethosomes (ethanol: PG = 5:5, w/w) were an efficient and stable transdermal delivery system.
CONCLUSION
The nicotine-encapsulated ethosomes containing ethanol and PG are considered to be safe and reliable as a transdermal administration agent, which does not irritate the skin.
Topics: Mice; Humans; Animals; Liposomes; Skin Absorption; Nicotine; Ethanol; Skin; Administration, Cutaneous; Propylene Glycol
PubMed: 37132146
DOI: 10.2174/1567201820666230428122845 -
International Journal of Pharmaceutics Jul 2020Tofacitinib citrate (TC) has recently gained interest in treating skin disorders such as psoriasis, atopic dermatitis and baldness. Unfortunately, the oral...
Tofacitinib citrate (TC) has recently gained interest in treating skin disorders such as psoriasis, atopic dermatitis and baldness. Unfortunately, the oral administration shows side effects, such as decreased neutrophil counts. To this end, the topical delivery of TC can be used to reduce the risk associated with systemic exposure. However, TC shows minimal absorption via skin. Hence, the objective of this study is to enhance the skin delivery of TC using a non-invasive approach. The liposomes based on propylene glycol, named as proposomes, carrying TC, were studied. The vesicle characteristics and in vitro skin permeation were assessed. The proposomes enhanced the skin permeability of TC by 4-11 folds. The composition of proposomes was found to affect the skin permeation and deposition of TC. The proposomes were stable for at least 6 months. Overall, proposomes were effective for targeted topical drug delivery.
Topics: Administration, Cutaneous; Cadaver; Chemistry, Pharmaceutical; Drug Delivery Systems; Drug Stability; Humans; Liposomes; Male; Middle Aged; Particle Size; Piperidines; Propylene Glycol; Protein Kinase Inhibitors; Pyrimidines; Skin Absorption
PubMed: 32565283
DOI: 10.1016/j.ijpharm.2020.119558