Toxicology of glycol ethers derived from propylene glycol: hematological, reproductive, and methodological evaluation (GEHRT1)

This study aims to determine the toxicokinetics (absorption, distribution, metabolism, and elimination [ADME]), as well as potential hematological changes (Part 1) and reproductive toxicity effects (Part 2), in humans exposed to two propylene glycol ethers for which human data are lacking.

Healthy female and male participants are exposed via inhalation for 2 hours to low concentrations of these compounds, both individually and as mixtures. Exposure is fully controlled using a 12 m³ exposure chamber specifically designed for this purpose. Blood and urine samples are collected before, during, and after exposure. Blood uptake, internal dose, and maximum blood concentration are thus determined, along with potential hematological changes. In addition, the ability of propylene glycol ethers to bind to hormonal receptors is assessed using CALUX (Chemical-Activated Luciferase gene eXpression) bioassays.

Glycol ethers are used as solvents in the manufacture of paints, adhesives, inks, cosmetics, cleaning products, and varnishes, for example. Their presence in consumer goods, in both occupational and domestic settings, can be considered ubiquitous, chronically exposing millions of people to potential health effects. Hematological effects—such as decreases in white blood cell, red blood cell, and platelet counts, as well as hemoglobin concentration and hematocrit—have been observed in rodents exposed to ethylene glycol ethers. Respiratory effects, such as shortness of breath and asthma, have also been reported in workers potentially exposed to glycol ethers.

Many ethylene glycol ether derivatives have been banned from household products and subjected to restrictions on industrial use because of their toxicity. As a result, the marketing of propylene glycol ethers has increased, as they are considered non-toxic. In Switzerland, there are no occupational exposure limits for many of these propylene glycol derivatives, meaning that workers may be exposed to high concentrations for unlimited periods of time.