POLYMERS BEYOND MICROPLASTICS: A COMPUTATIONAL TOXICOLOGY PERSPECTIVE

The improper management of plastic waste poses a significant environmental challenge, particularly
due to the persistence of microplastic debris across various ecosystems. These particles exhibit
ecotoxicological potential, causing adverse effects on both aquatic and terrestrial organisms with
possible bioaccumulation and associated risks to human health. According to the literature,
microplastics derived from disposable items such as cups and cutlery often contain polymers like
polyethylene terephthalate (PET), polylactic acid (PLA), polybutylene succinate (PBS), polyvinyl
chloride (PVC), and polystyrene (PS). Characterizing the toxicokinetic and toxicodynamic profiles of
these polymers is essential for evaluating their biological and environmental impacts. In this context,
in silico approaches have emerged as powerful tools for predicting pharmacokinetic (absorption,
distribution, metabolism, excretion) and toxicological (ADMETox) properties, enabling rapid, reliable,
and cost-effective analyses. This study aimed to assess the ADMETox profiles of PET, PLA, PBS,
PVC, and PS using computational methodologies combined with a literature review. Chemical
structures were retrieved in SMILES format from the PubChem database and submitted to
SwissADME, ADMETlab 3.0, and pkCSM platforms for the prediction of physicochemical,
pharmacokinetic, and toxicological parameters. A consensus analysis was conducted across the
different algorithms employed. The results revealed substantial differences among the polymers. PLA
and PBS exhibited greater water solubility (LogS: 1.27 and -0.019, respectively), higher excretion
potential, and limited central nervous system permeability. PET showed an intermediate profile, with
moderate lipophilicity (LogP: 1.62), high intestinal absorption, and notable metabolic stability.
Conversely, PS and PVC demonstrated elevated toxicological potential, including the ability to cross
the blood–brain barrier, increased lipophilicity (LogP: 3.06 and 1.52), and strong plasma protein
binding (>90%), along with signs of carcinogenicity—suggesting a heightened systemic risk. All
polymers displayed low dermal permeability (LogKp < -2), indicating minimal risk through cutaneous
exposure. These findings highlight the need for greater vigilance regarding the toxicological risks of
PS and PVC. Moreover, the ADMETox characterization supports the urgency of developing effective
biodegradation strategies. Future efforts will focus on identifying and optimizing biodegrading
enzymes to mitigate the environmental and health impacts, fostering sustainability through
eco-compatible solutions.