Iatrogenic Microplastic Exposure: A Possible and Underrecognized Healthcare-Associated Exposure Framework in Human Medicotoxicological Risk.

Microplastics (MPs) are emerging environmental contaminants detected not only in water, soil, and air but also in human biological samples. To date, three main exposure routes have been identified. Currently, the principal exposure routes examined in scholarly works are oral, inhalational, and dermal. This paper explores iatrogenic microplastic exposure (IME) as an underrecognized healthcare-associated source of exposure and suggests that, in certain clinical contexts involving invasive, device-mediated, or direct systemic contact, IME may be considered a possible fourth route of exposure. IME is the introduction of microplastics into the human body through medical interventions. A literature-based conceptual review was conducted focusing on the materials and additives used in pharmaceutical formulations, intravenous systems, and medical devices. Particular attention was given to polymer-based excipients and plasticizers (e.g., phthalates, PEG, triacetin) found in enteric drug coatings and infusion packaging. Findings suggest that polymer-derived particles may enter systemic circulation via intravenous fluids, implantable devices, or oral medications, especially under conditions of heat, pressure, or prolonged contact. Such materials, though deemed biocompatible, may contribute to nanoplastic load and chronic exposure risks. Vulnerable groups such as neonates, oncology patients, and ICU populations may face disproportionate exposure. This calls for re-evaluation of plastic use in medical practice, improved regulatory oversight of pharmaceutical excipients, and innovation in plastic-free biomedical materials. Integrating this route into toxicological and epidemiological frameworks will enrich our understanding of microplastic-related health risks and broaden the scope of environmental health strategies.