Effects of oral administration of a high-molecular-weight crosslinked polyacrylate in rats

Oral feeding studies of a crosslinked, high-molecular-weight polyacrylate polymer (PA) were conducted to (1) characterize the biological effects following exposure to either 0, 300, 1000, or 3000 mg PA/kg/day for 93 days; (2) characterize the fecal and urinary mineral excretion at these same dose levels; and (3) monitor the absorption, distribution, and excretion (ADE) of radiolabeled PA following a single oral exposure. The subchronic study results indicate that dietary intake of up to 3000 mg/kg/day PA had no adverse histopathology, hematology, body weight, or clinical chemistry effects in rats. Dietary exposure to PA did, however, result in an elevation in urinary excretion of sodium and phosphorus, whereas excretion of magnesium, calcium, and potassium was lowered. A more detailed study demonstrated that although the urinary excretion of these minerals was changed, total recovery of the minerals (feces + urine), except for sodium, was not different from that for controls. An increase in sodium excretion was expected since PA was in the form of a sodium salt. The ADE studies following a single oral dose of PA indicate that the majority of dosed PA (91.9%) was excreted in the feces. As expected, a small percentage (approximately 3.5%) was absorbed, possibly metabolized, and excreted. In summary, the oral administration of high levels of PA resulted in (1) no histological, hematological, or clinical chemistry changes; (2) no alteration in the overall mineral excretion (feces + urine) with the exception of sodium; and (3) primarily fecal excretion of orally administered PA.