His paper did use “worst-case” assumptions, but we can’t ignore this point entirely. Underlying renal insufficiency and hepatic dysfunction raise risk for toxicity. I think for those of us with curly hair, propylene glycol's main benefit is the fact that it is a humectant, and a pretty effective one at that. All the usual cautions apply with regard to its capabilities to attract water to the hair from the environment or to draw water from the hair to itself. To review relevant content, see Mechanism of Toxicity in this section. Acidosis and acute renal failure may result from deposition of calcium oxalate crystals in the kidneys. It is a synthetic liquid substance that absorbs water and is used by the chemical, food, and pharmaceutical industries for a wide variety of reasons. Propylene glycol is used in air sanitization and hard surface disinfection and dipropylene glycol is used in air sanitization. Unmetabolized ethylene glycol contributes to CNS depression. Signs of metabolic acidosis due to the metabolites may become apparent late in stage 1. In April 2018, the New York Times reported on the presence of formaldehyde in e-cigarettes, "E-cigs often use propylene glycol or glycerol to help transport nicotine and flavors and to create the big vapor cloud. To review relevant content, see Table 1 in this section. Writer Tonya McKay Becker is a curly-haired polymer scientist and cosmetic chemist whose academic and industrial research experience have provided her with expertise in the fundamentals and applications of polymer science and colloid chemistry. Propylene glycol should not be a feared ingredient. After the glycoaldehyde forms (at 4-12 hours) and metabolic acidosis begins, CNS depression—if it is a serious intoxication—can lead to the following effects: An osmolal gap, without metabolic acidosis, or an anion gap may be seen before significant metabolism of ethylene glycol occurs. It is frequently used in deodorants and antiperspirants. But in larger doses, it can take a toll on your kidneys and liver. Even with prolonged direct exposure, there is little to no skin irritation or sensitization. As ethylene glycol is metabolized, the osmolal gap, if present, will decrease and an anion gap metabolic acidosis evolves. Propylene glycol → lactic acid → pyruvic acid → CO2 + water. A. oxidative phosphorylation and cellular respiration Conclusion: Propylene glycol toxicity is a potentially life-threatening iatrogenic complication that is common and preventable. I do not personally consider a petroleum-sourced product to be a bad thing, as I consider the final structure and its properties to be more relevant than the source (unless contamination is a concern). Propylene glycol (PG) is absorbed from the gastrointestinal tract following oral administration 2,3,4; Topical exposure is unlikely to produce toxic effect unless applied to open wounds or burn sites 5; Between 12% and 46% of PG is cleared unchanged by the kidney and the rest undergoes hepatic metabolism 6; Metabolism 7,8,9. Experimentally, propylene glycol administration in dogs at 2 g/kg/day has caused no adverse effects. While few chemicals are entirely without risk, propylene glycol is considered to be safe at the low concentrations, used in personal care products and even food products. Which of the following cellular biochemical reactions can be inhibited by acid and aldehyde metabolites of ethylene glycol? How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Toxicity from ingestion has been reported only once, when a man drank the contents of an ice pack containing propylene glycol, which most likely was not of a food-grade quality and may have contained other potentially harmful chemicals. Symptoms of Chemical poisoning - Propylene Glycol including 10 medical symptoms and signs of Chemical poisoning - Propylene Glycol, alternative diagnoses, misdiagnosis, and correct diagnosis for Chemical poisoning - Propylene Glycol signs or Chemical poisoning - Propylene Glycol symptoms. We’ve known for a long time that when we heat these so-called carrier fluids they can transform into formaldehyde." Unless you have the perfect atmospheric conditions, you may experience problems with this ingredient. Other organic solvents miscible with water such as ethyl alcohol and acetone have been used but are undoubtedly pharmacologically active besides being highly deleterious to the tissues they contact directly after injection. Gaunt, IF, Carpanini, FMB, Grasso, P and Lansdown, ABG, "Long-term toxicity of propylene glycol in rats, Food and Cosmetics Toxicology," April 1972, 10(2), pages 151-162. Propylene glycol toxicity is not expected in normal environmental or occupational exposures. In cats, ingestion of a diet containing 6%–12% PG can result in Heinz body formation and decreased RBC survival. D. All of the above. Lightly moisturizes: Herrmann adds that as a humectant, it also offers moisturizing benefits and smoothes the skin with a light, non … The oral LD50 in rats was 3089 and 9456 mg/kg EGPE and EGPEA, respectively. An ingredient found in many personal-care products like shampoo, hair conditioner, and styling product, propylene glycol is widely used because of its relatively low cost and versatile nature. Participate in product testing surveys discussions etc. Enhanced skin absorption, Use restrictions (low), Non-reproductive organ system toxicity (moderate), and Irritation (skin, eyes, or lungs) (high) This depression appears similar to ethanol intoxication, but without the characteristic odor of alcohol. The elimination half-life for propylene glycol is approximately four hours, and there is no bioaccumulation (buildup in the body over time). Propylene glycol is a commonly used solvent for oral, intravenous, and topical pharmaceutical preparations. Propylene glycol CASRN 57-55-6 | DTXSID0021206. The concern arises when propylene glycol is heated up and inhaled. C. stage 3 (24 – 72 hr) The MSDS recommends avoiding direct handling due to potential irritation, which is a smart recommendation for any chemical--this is not an indication of the level of toxicity. Propylene glycol has been designated by the FDA as “generally recognized as safe,” or GRAS, for consumption; however, according to the Federal Agency for Toxic Substances and Disease Registry, "We have little information about what happens to propylene glycol in the air." The salt accomplishes this by lowering the freezing point of water. Propylene glycol is safe in small doses. Kidney damage usually develops 24-72 hours after exposure. Moreover, there are … It will not evaporate easily (which may cause dry hair). The concentrations of propylene glycol used in this study are significantly higher It is used as a solvent for pigments in cosmetics. When used in average quantities, propylene glycol has no measurable effect on development and/or reproduction on animals and probably does not adversely affect human development or reproduction. (Friedman, Greenberg et al. Calcium oxalate crystals may appear in the urine as early as stage 1, but absence of these crystals does not rule out the diagnosis of ethylene glycol poisoning. They also may lead to hypocalcemia secondary to calcium oxalate precipitation. If product manufacturers are finding replacement ingredients to fulfill the same purposes in their formulas served by propylene glycol, I see no harm in that. Editor's Note: Since the original publication of this article discussing the use of propylene glycol in personal hair products and food, the popularity of e-cigarettes has brought increased attention to this ingredient. Delayed clinical toxicity results from conversion of ethylene glycol to metabolites of greater toxicity. A. stage 1 (0.5 – 12 hr) Unlike its dangerous and frequently lethal cousin, ethylene glycol, PG is easily metabolized by the liver into normal products of the citric acid metabolic cycle, which are completely nontoxic to the body. B. stage 2 (12 – 24 hr) 8. B. protein synthesis Propylene glycol is used as an organic solvent and diluent in pharmaceuticals and many other industrial applications. For this reason, some items on this page will be unavailable. oxidative phosphorylation and cellular respiration, gastrointestinal irritation (nausea and vomiting). There were no observable effects on their health or behavior. This is an example of a "safe" chemical being used as antifreeze. Dogs fed dietary doses of propylene glycol for two years (2,000 or 5,000 mg/kg/day) showed Archived IRIS Summary (PDF) (5 pp, 89 K) ... Additional EPA toxicity information may be available by visiting the following sites: Human Health Benchmarks for Pesticides (HHBP). 7. Propylene glycol (PG) is a commonly used solvent for oral, intravenous, and topical pharmaceutical agents. McKay, T. "Humidity, Humectants and Hair", online publication, Aug. 2007. Propylene Glycol is a propanediol that exists as a clear, colorless and hygroscopic liquid and consists of propane where the hydrogens at positions 1 and 2 are substituted by hydroxyl groups. CNS depression begins soon after exposure, lasting for up to 12 hours after ingestion. I am an avid supporter of using natural products, avoiding putting toxins into our bodies whenever possible or practical. describe the three stages of ethylene glycol toxicity. The main toxicity results from hepatic metabolism of ethylene glycol to glycoaldehyde, glycolate, glyoxylate, and oxalate. Propylene glycol is used as one of the three main ingredients in e-cigarettes, along with nicotine and flavoring. Propylene glycols have relatively low toxicity. Propylene glycol is a common ingredient in antifreeze, lubricants, and products of plasticity. CNS depression begins soon after exposure, lasting for up to 12 hours after ingestion. Propylene glycol (PG) is one of the least toxic glycols. 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