Polysorbate 80 has low-grade toxicity in both mice and rats when administered by the intraperitoneal and oral routes, producing mild to moderate depression of the central nervous system, significant reductions in locomotor activity and rectal temperatures, demonstration of ataxia and paralysing activity, and enhancement of pentobarbital sleep duration.
It had a dose-dependent antihypertensive effect in dogs administered intravenously.
Polysorbate 80 had no direct stimulatory or relaxant effect on the guinea-pig ileum or rat uterus, but it antagonised contractions induced by acetylcholine, histamine, barium, 5-hydroxytryptophan and carbachol in a dose-dependent manner.
A direct relaxant effect was observed on rabbit jejunum. Dose-dependent myocardial inhibition was observed on guinea pig and rabbit paired atrial preparations. In electrically driven guinea pig left atrial preparations, it exhibited a dose-dependent negative inotropic effect. It does not induce diuresis in rats below a dose of 2.5 ml/kg.