Lack of influence of etretinate on the intestinal absorption of D-xylose and of phytomenadione (vitamin K1) as representatives of hydrophilic and lipophilic compounds.

The possible influence of the aromatic retinoid etretinate (Tigason ) on the intestinal absorption of D-xylose and phytomenadione (vitamin K1) has been studied in 7 healthy male volunteers between 22 and 25 years of age. D-xylose and phytomenadione were selected as being representative of water-soluble and fat-soluble test compounds, respectively. Following an oral dose of 25 g D-xylose the plasma levels and urinary excretion pattern of the compound were followed over 6 h. The plasma concentrations of phytomenadione after an oral dose of 20 mg of the vitamin were measured over 14 h. These absorption tests were performed before (baseline) and at the end of a 3-week treatment period with 25 mg b.i.d. etretinate. In addition some parameters on the serum lipid status pre and post etretinate treatment were monitored. The pharmacokinetic and biochemical determinants after treatment with etretinate were referenced to the pretreatment values and nonparametric confidence intervals (a less than 0.05) for these ratios were calculated. With respect to the area, AUC, under the D-xylose plasma concentration--time curve (0.79 less than or equal to RAUC = 1.00 less than or equal to 1.17) as well as to the cumulative amount excreted into urine over 6 h (0.90 less than or equal to RSUM = 1.04 less than or equal to 1.28) and to renal clearance (0.91 less than or equal to Rcl = 1.05 less than or equal to 1.25), no effect of etretinate on absorption and/or renal handling of D-xylose was discernible.(ABSTRACT TRUNCATED AT 250 WORDS)