Comparative hydrolytic stability of alternative PVC plasticisers under accelerated conditions: a worst-case approach for material–formulation compatibility
Abstract
Poly(vinyl chloride) (PVC) medical devices increasingly use alternative plasticisers such as di(2ethylhexyl) terephthalate (DEHT), tris(2-ethylhexyl) trimellitate (TOTM) and diisononyl cyclohexane-1,2-dicarboxylate (DINCH) following restrictions on di(2-ethylhexyl) phthalate (DEHP). Although migration of these compounds has been widely investigated, their intrinsic solution-phase stability after release remains poorly documented. This study established a unified chromatographic and kinetic framework to directly compare DEHT, TOTM, and DINCH under identical accelerated conditions. A worst-case model was developed using methanolic media adjusted over an apparent pH range of 2.1-11.9 at 35 °C. Parent-plasticiser disappearance was monitored by RP-HPLC-DAD, while additional chromatographic peaks were followed qualitatively. Detailed kinetic model comparison focused on apparent pH 11.9. No measurable parent-compound disappearance was observed under acidic or neutral conditions. DEHT and TOTM began to degrade under moderately alkaline conditions, with the greatest discrimination observed at an apparent pH of 11.9. Under this condition, the apparent half-lives were approximately 12.1 min for TOTM, 161.6 min for DEHT and 18.62 days for DINCH. The TOTM value was treated as a descriptive estimate due to its rapid disappearance, whereas first-order kinetics were strongly supported for DEHT and DINCH. The temporal evolution of additional peaks was compatible with consecutive transformation pathways, although the corresponding compounds were not structurally confirmed. These pHdependent differences may partly reflect molecular architecture and the local environment of J o u r n a l P r e -p r o o f Journal Pre-proof 2 ester functions, but the structure-reactivity interpretation remains qualitative. Because methanol-assisted transesterification could not be excluded, the term "hydrolysis" was used operationally. This solution-phase model complements, rather than replaces, migration, toxicological, material-performance and regulatory assessments.
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BibTeX
@article{benali2026comparative,
title = {{Comparative hydrolytic stability of alternative PVC plasticisers under accelerated conditions: a worst-case approach for material–formulation compatibility}},
author = {Wiam Benali and Lionel Tortolano and Tahar Sif Eddine Bouchema and Lynda Chibane and Katia Manerlax and Mustapha Touati and Johanna Saunier and Najet Yagoubi},
journal = {Results in Chemistry},
year = {2026},
month = sep,
doi = {10.1016/j.rechem.2026.103766},
url = {https://univ-paris-dauphine.hal.science/hal-05742176v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Comparative hydrolytic stability of alternative PVC plasticisers under accelerated conditions: a worst-case approach for material–formulation compatibility
AU - Wiam Benali
AU - Lionel Tortolano
AU - Tahar Sif Eddine Bouchema
AU - Lynda Chibane
AU - Katia Manerlax
AU - Mustapha Touati
AU - Johanna Saunier
AU - Najet Yagoubi
PY - 2026
DA - 2026/09/08
JO - Results in Chemistry
DO - 10.1016/j.rechem.2026.103766
UR - https://univ-paris-dauphine.hal.science/hal-05742176v1
AB - Poly(vinyl chloride) (PVC) medical devices increasingly use alternative plasticisers such as di(2ethylhexyl) terephthalate (DEHT), tris(2-ethylhexyl) trimellitate (TOTM) and diisononyl cyclohexane-1,2-dicarboxylate (DINCH) following restrictions on di(2-ethylhexyl) phthalate (DEHP). Although migration of these compounds has been widely investigated, their intrinsic solution-phase stability after release remains poorly documented. This study established a unified chromatographic and kinetic framework to directly compare DEHT, TOTM, and DINCH under identical accelerated conditions. A worst-case model was developed using methanolic media adjusted over an apparent pH range of 2.1-11.9 at 35 °C. Parent-plasticiser disappearance was monitored by RP-HPLC-DAD, while additional chromatographic peaks were followed qualitatively. Detailed kinetic model comparison focused on apparent pH 11.9. No measurable parent-compound disappearance was observed under acidic or neutral conditions. DEHT and TOTM began to degrade under moderately alkaline conditions, with the greatest discrimination observed at an apparent pH of 11.9. Under this condition, the apparent half-lives were approximately 12.1 min for TOTM, 161.6 min for DEHT and 18.62 days for DINCH. The TOTM value was treated as a descriptive estimate due to its rapid disappearance, whereas first-order kinetics were strongly supported for DEHT and DINCH. The temporal evolution of additional peaks was compatible with consecutive transformation pathways, although the corresponding compounds were not structurally confirmed. These pHdependent differences may partly reflect molecular architecture and the local environment of J o u r n a l P r e -p r o o f Journal Pre-proof 2 ester functions, but the structure-reactivity interpretation remains qualitative. Because methanol-assisted transesterification could not be excluded, the term "hydrolysis" was used operationally. This solution-phase model complements, rather than replaces, migration, toxicological, material-performance and regulatory assessments.
SN - 2211-7156
ER -