The Effect of Dose and Concentration on D‐Xylose Absorption in Healthy, Immature Dogs

Abstract
Nine combinations of dosages and concentrations of D‐xylose were given orally to eight clinically normal, immature dogs. The concentrations and dosages of D‐xylose consisted of 5%, 10%, and 20% at 250 mg/kg, 500 mg/kg, and 750 mg/kg. Serum samples were collected at 0, 30, 60, 90, 120, and 180 minutes. Serum xylose was quantitated using the phloroglucinol microassay technique. A peak in serum xylose concentration was seen for each treatment combination at 60 or 90 minutes after dosing. The dosage effect was important in influencing serum xylose values (P < 0.0001). As the test solution dosages increased from 250 mg/kg to 500 mg/kg and 750 mg/kg, serum xylose values (when dosage was analyzed over the length of the entire test) rose linearly (R2= 0.98). The treatment combinations of 5% and 20% xylose solutions dosed at 750 mg/kg produced the highest serum xylose values at the 60‐and 90‐minute peak intervals. The independent effect of concentration was significant (p < 0.001) but was overridden by the stronger dosage effect. Serum xylose concentrations varied little statistically (p > 0.05) when the 5%, 10%, and 20% solutions were compared at a specific dosage.