Proabsorptive action of gum arabic in isotonic solutions orally administered to rats. II. Effects on solutes under normal and secretory conditions.

Gum arabic (GA) is a natural proteoglycan with proabsorptive capacity attributable to its physico-chemical properties. Previous experiments showed that in rats oral administration of GA in an isotonic solution had a generally positive effect. This study extends the investigation to include acetaminophen and to evaluate whether GA could also act under secretory conditions induced by theophylline. Test solutions were orally administered to rats under CO2 anesthesia and blood concentrations followed for 3 hr. The secretory effects of theophylline were clearly observed for sodium and zinc. Addition of GA resulted in a more rapid rate of glutamate absorption, under normal physiologic conditions, as indicated by the higher area under the curve (AUC). There were no differences in the presence of theophylline. Acetaminophen blood concentrations peaked about 30 min after administration, and the AUC in rats that received GA was higher than in those that got the solution without GA. AUCs for total body water distribution with time and those for glucose concentrations were indistinguishable whether the solutions contained or did not contain either GA or theophylline. The results confirm that oral administration of GA can accelerate absorption of some solutes, including pharmacologic agents.