Absorption of polyethylene glycol 400 administered orally to mature and senescent rats

Abstract

Absorption of polyethylene glycol 400 administered orally to mature and senescent rats. Lin, C.F., and Hayton, W.L. Polyethylene glycol 400 (PEG 400), a probe for studying GI absorptive capacity, is a mixture of homologous compounds differing in molecular weight (mw). The bio-availability of PEG 400 was studied in senescent (age 32–37 months) and mature (age 17–20 months) male Sprague-Dawley rats, by giving PEG 400 both orally and intravenously and measuring the amounts of the component molecular species excreted into the urine. After intravenous administration, urinary recovery of the various components increased with an increase in mw. The pattern of urinary recovery was similar in both groups, and led to the conclusion that the urinary disposition of PEG 400 was not affected by senescence. After oral administration, the extent of absorption of the low mw components was higher but that of the high mw components was lower in senescent rats than in the mature animals. These senescence-related alterations in the bioavailability of PEG 400 were attributed to age-dependent changes in intestinal transit rate and mucosal permeability. Similar results were observed in a preliminary longitudinal study.