Participate in product testing surveys discussions etc. For this reason, some items on this page will be unavailable. We’ve known for a long time that when we heat these so-called carrier fluids they can transform into formaldehyde." 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. 8. Unmetabolized ethylene glycol contributes to CNS depression. B. stage 2 (12 – 24 hr) Even with prolonged direct exposure, there is little to no skin irritation or sensitization. However, I hesitate to support marketing materials that use this as a selling point. The concern arises when propylene glycol is heated up and inhaled. 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. The toxicity of propylene glycol is very low. Federal Agency for Toxic Substances and Disease Registry. The application of propylene glycol that is most relevant to those of us with curly hair is as a humectant. A few rare incidents have occurred where a person ingested a large quantity of propylene glycol and suffered some liver and neurological effects as a result, but these were short-lived and subsided once the material was metabolized and excreted. It is found in hand cleansers and disinfecting gels. As an inert ingredient, propylene glycol is formulated into end- 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). 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. It is a common additive in shaving creams and gels. These metabolites inhibit. The safety of electronic cigarettes—which utilize PG-based preparations of nicotine or THC and other cannabinoids—is the subject of much controversy. The following cardiorespiratory symptoms may appear 12-24 hours after ingestion, The following conditions may develop in this stage, Formation of oxalic acid may lead to deposition of calcium oxalate crystals in. 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. In cats, ingestion of a diet containing 6%–12% PG can result in Heinz body formation and decreased RBC survival. Propylene glycol This ingredient has many functions, including acting as a humectant, preservative, and more. The FDA classifies propylene glycol as an additive that is “generally recognized as safe” for use in food – not exactly a ringing endorsement. However, some manufacturers have recently made the decision to no longer include propylene glycol in their products. Experimentally, propylene glycol administration in dogs at 2 g/kg/day has caused no adverse effects. Propylene glycol is used as an organic solvent and diluent in pharmaceuticals and many other industrial applications. Severe ethylene glycol poisoning may go through three stages: CNS depression, cardiopulmonary toxicity, and renal toxicity (Table 1) aerosols, propylene glycol may be considered as a solvent with acceptable toxicity. The oral LD 50 of PG in dogs is ~9 mL/kg. It is used as a solvent for pigments in cosmetics. But high doses of the chemical are added to many IV medications. This depression appears similar to ethanol intoxication, but without the characteristic odor of alcohol. oxidative phosphorylation and cellular respiration, gastrointestinal irritation (nausea and vomiting). 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. Most deaths from ethylene glycol poisoning occur during stage 2. Propylene glycol is a completely water-soluble material that will not build up on the hair. This depression appears similar to ethanol intoxication, but without the characteristic odor of alcohol. Propylene glycol is a common ingredient in antifreeze, lubricants, and products of plasticity. Ethylene glycol itself is toxic, but its harmful effects mainly result from the accumulation of its more toxic metabolites. To review relevant content, see Table 1 in this section. 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. Large doses and unusual circumstances are necessary for the development of propylene glycol toxicity. 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. The oral median lethal dose (LD50) of propylene glycol in dogs has been reported to be ~9 ml/kg body weight. The oral LD 50 of PG in dogs is ~9 mL/kg. 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." You won’t get a large enough dose in your food to cause this problem. Propylene glycol (also known as 1,2 propanediol) is a relatively small molecule with two alcohol (hydroxyl) groups (-OH). CNS depression begins soon after exposure, lasting for up to 12 hours after ingestion. 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. Unless you have the perfect atmospheric conditions, you may experience problems with this 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. Patients who present late may have renal failure with normal osmolal and anion gaps and no acidosis or measurable ethylene glycol levels (Ford M 1991). The manifestations of propylene glycol toxicity include central nervous system depression, seizures, cardiac arrhythmias, respiratory arrest, hemolysis, and renal failure (2). Although less toxic than EG, ingestion of propylene glycol (PG) may be associated with a toxic syndrome similar to the acute phase of EG toxicosis. The following conditions characterize the third phase, Prolonged, rarely permanent, kidney failure is distinguished by. Lightly moisturizes: Herrmann adds that as a humectant, it also offers moisturizing benefits and smoothes the skin with a light, non … Acute oral toxicity studies on polypropylene glycols of various molecular weights (300 to 3900 Da) have indicated LD50 values (rats) ranging from 0.5 to >40g/kg. 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. Kidney damage usually develops 24-72 hours after exposure. It is a colorless, odorless liquid that is completely water-soluble. It subsides quickly once the area is flushed. CNS depression begins soon after exposure, lasting for up to 12 hours after ingestion. In cats, ingestion of a diet containing 6%–12% PG can result in Heinz body formation and decreased RBC survival. Its inclusion in a formula can fulfill a variety of purposes, which makes it a popular choice by the cosmetics chemist. 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. I am an avid supporter of using natural products, avoiding putting toxins into our bodies whenever possible or practical. (Friedman, Greenberg et al. 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. Propylene glycol CASRN 57-55-6 | DTXSID0021206. > Propylene glycol ingested at toxic doses can cause central nervous system depression and lactic acidosis, Brutlag says. A. stage 1 (0.5 – 12 hr) This is not relevant to consumers using a product by the teaspoonful, if that. CE Expiration Date: October 3, 2012 The elimination half-life for propylene glycol is approximately four hours, and there is no bioaccumulation (buildup in the body over time). Conclusion: Propylene glycol toxicity is a potentially life-threatening iatrogenic complication that is common and preventable. 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. 7. This process helps melt snow and ice and prevent development of dangerous icy conditions. Currently there is little research on the long-term effects of inhalation of propylene glycol through e-cigarettes. They also may lead to hypocalcemia secondary to calcium oxalate precipitation. The oral LD50 in rats was 3089 and 9456 mg/kg EGPE and EGPEA, respectively. The word is frequently used to alarm consumers, and is simply a scientific term used to describe the lowering or depression of the freezing point of a liquid. Acidosis and acute renal failure may result from deposition of calcium oxalate crystals in the kidneys. Ethylene glycol is a central nervous system (CNS) depressant that can produce acute effects similar to those of ethanol. Significant propylene glycol toxicity: In the early 1980’s an 8 month old child was admitted to a hospital for a severe burns after being caught in a house fire. Propylene glycol CASRN 57-55-6 | DTXSID0021206. Propylene glycol (PG) is a commonly used solvent for oral, intravenous, and topical pharmaceutical agents. In an interesting study, some rats were fed propylene glycol at amounts equal to 5% of all of their food intake every day for two years, which is a pretty huge volume over a large portion of their lifetime. Propylene glycol should not be a feared ingredient. Propylene glycol is used in air sanitization and hard surface disinfection and dipropylene glycol is used in air sanitization. In fact, Propylene glycol is one of the solvents included in the FDA inactive ingredients guide for various preparations including inhalation. There were no observable effects on their health or behavior. It should be considered whenever a patient has an unexplained anion gap, unexplained metabolic acidosis, hyperosmolality, and/or clinical deterioration. 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). 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. This is an example of a "safe" chemical being used as antifreeze. Delayed clinical toxicity results from conversion of ethylene glycol to metabolites of greater toxicity. PG is a synthetic product obtained from the hydration of propylene oxide, which is derived from petroleum products. Our website is made possible by displaying online advertisements to our visitors. It has not been found to cause cancer, damage genes or interfere with fertility or reproduction. 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. Use plenty of moisturizing products to help lock moisture into your hair shaft, which can help prevent any potential problems caused by a humectant. Propylene glycol is non-toxic when ingested, even in reasonably large amounts. sensitivity of cats to propylene glycol suggests that the effects on blood reported in studies involving this species are not relevant to the evaluation of propylene glycol toxicity in humans. Download Printer-Friendly version [PDF - 496 KB], Upon completion of this section, you should be able to. Propylene glycol is not as toxic as another common antifreeze ingredient known as ethylene glycol; however, it is still poisonous and dogs require medical treatment if ingested. It is also important to note that it is a diol with low volatility, meaning it will not evaporate easily and cause dry hair in the manner of low molecular weight alcohols such as SD alcohol and isopropyl alcohol. A. oxidative phosphorylation and cellular respiration An example is the application of salt to roads and walkways in a snowstorm. Propylene glycol → lactic acid → pyruvic acid → CO2 + water. According to S cholar Chemistry’s (now Ward’s Chemistry) material safety data sheet, problems associated with liquid GP include irritation and sensitivity to the eyes, skin, and mucous membranes. These deposits can cause tissue injury. Propylene glycol is safe in small doses. 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. The salt accomplishes this by lowering the freezing point of water. Both experimental and anecdotal evidence to date indicate PG to be completely non-carcinogenic, despite its "petroleum-based" origin. The Truth About Propylene Glycol, According to a Chemist. The accumulation of organic acid metabolites, especially glycolic acid, results in anion gap metabolic acidosis which affects many cellular functions. His paper did use “worst-case” assumptions, but we can’t ignore this point entirely. It applies like a humectant (attracts water to the hair). It can be used as a preservative due to its antifungal and antimicrobial properties. Note: Javascript is disabled or is not supported by your browser. These CNS effects predominate during the first hours after exposure. The main toxicity results from hepatic metabolism of ethylene glycol to glycoaldehyde, glycolate, glyoxylate, and oxalate. Enhanced skin absorption, Use restrictions (low), Non-reproductive organ system toxicity (moderate), and Irritation (skin, eyes, or lungs) (high) As a curly, it would be wise to be aware if you are using products that contain this ingredient, just in case you observe increased frizz or dryness. Which of the following cellular biochemical reactions can be inhibited by acid and aldehyde metabolites of ethylene glycol? D. stages 2 and 3 ( 12 – 72 hr). Propylene glycol is a commonly used solvent for oral, intravenous, and topical pharmaceutical preparations. /LABORATORY ANIMALS: Acute Exposure/ Propylene glycol was relatively harmless (LD50 = 21 g/kg) in acute oral toxicity studies involving rats. 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. Dogs fed dietary doses of propylene glycol for two years (2,000 or 5,000 mg/kg/day) showed How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Signs of metabolic acidosis due to the metabolites may become apparent late in stage 1. Forms a loose “S” very easily straightened, Forms a definite “S” shaped like a corkscrew, Very tight curl when stretched creates an “S”, Hair intentionally matted to form "ropes", Guides and resources for easy product selection, Learn how to read your hair product labels, Easy-to-make recipes for all your haircare needs, Community member favorites make up this coveted list, Chat with curl friends about your favorite curly topics. 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. This database provides human health benchmarks for pesticides that may be present in drinking water. As ethylene glycol is metabolized, the osmolal gap, if present, will decrease and an anion gap metabolic acidosis evolves. Sign up for our newsletter to get more tips and tricks. Do not be alarmed by the term antifreeze or by the chemical, propylene glycol. Propylene glycol toxicity is metabolized to compounds that are normal constituents of the citric acid cycle. B. protein synthesis Ethylene glycol ingestion results initially in CNS effects. Although less toxic than EG, ingestion of propylene glycol (PG) may be associated with a toxic syndrome similar to the acute phase of EG toxicosis. The acute toxicity of ethylene glycol monopropyl ether (EGPE) and ethylene glycol monopropyl ether acetate (EGPEA) was determined in a series of standardized tests. Tachypnea generally appears in which of the following stages: Although it is considered safe, large intravenous doses given over a short period of time can be toxic. Propylene glycol poisoning in dogs is caused by ingesting propylene glycol. The concentrations of propylene glycol used in this study are significantly higher Propylene glycol is used as one of the three main ingredients in e-cigarettes, along with nicotine and flavoring. Estimated levels of exposure to propylene glycol and glycerine are close enough to [workplace limits] to warrant concern. Propylene glycol toxicity is not expected in normal environmental or occupational exposures. Moreover, there are … The child was treated with silver sulfadiazine topically, propylene glycol is the solvent in this therapeutic . It is a solvent for fragrances and preservatives. It will not evaporate easily (which may cause dry hair). Approximately 45 percent of any ingested PG is excreted directly from the body and never even comes into contact with the liver. This is possibly due to misinformation and propaganda circulated on the Internet in the interest of marketing "natural" products. For more information about this message, please visit this page: Agency for Toxic Substances & Disease Registry, Environmental Health and Medicine Education, Ethylene Glycol and Propylene Glycol Toxicity, Download Printer-Friendly version [PDF - 496 KB], Agency for Toxic Substances and Disease Registry, Inebriation, euphoria, ataxia, slurred speech, drowsiness, irritation, restlessness, and disorientation, Mild hypertension, tachycardia, and shock, Tachypnea, adult respiratory distress syndrome, pulmonary edema, and pneumonitis, Metabolic acidosis with elevated anion gap and decreased osmolal gap, possible tetany from hypocalcemia, and hyperventilation, Flank pain, costovertebral angle tenderness, oliguric renal failure, hyperkalemia, and hypocalcemia, explain the mechanism of ethylene glycol toxicity and. Of ethylene glycol to metabolites of ethylene glycol itself is toxic, but we can ’ get. 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