The effect of adsorbed poloxamer 188 and 407 surfactants on the intestinal uptake of 60-nm polystyrene particles after oral administration in the rat

The surface properties of 60-nm polystyrene particles were modified by the adsorption of poloxamer 188 and 407 surfactants, and the effect of this change on the intestinal uptake of the particles studied. In comparison to uncoated polystyrene particles, the surfactant-coated particles had an increased particle diameter, as measured by photon correlation spectrometry, and lower zeta potential. Uptake of the coated polystyrene particles by gut epithelial tissue was studied in female Sprague-Dawley rats (180 g, 9 weeks old) after 5 days oral dosing by gavage. The small and large intestine was divided into lymphoid and non-lymphoid tissue, prior to analysis for polystyrene by gel permeation chromatography and visualization of particle uptake using fluorescent microscopy. The adsorption of poloxamer surfactants onto the polystyrene particles appeared to completely inhibit particle uptake in the small intestine. Polystyrene uptake was shunted to the large intestine, with the detection in this region of approximately 3% and 1.5% of the dose of poloxamer 407 and 188 coated particles, respectively. This uptake was less than the 10% uptake across the entire GI tract (5.1% uptake in the large intestine) determined for uncoated polystyrene particles.