Abstract
The absorption, distribution and excretion of $^{14}C$ labeled YH1885 {5,6-Dimethyl-2(4-fluorophenylamino)-4-(1-methyl-1,2,3,4-tetrahydroisoquinolin-2-yl)pyrimidine hydroc hloride), a new proton pumpinhibitor, were investigated in rats after a single administration of $^{14}C$-YH1885. 1. After intravenous administration of 5mg/kg, the blood level of radioactivity declined in a biphasic fashion with the mean terminal elimination half-life of 12.4hr. 2. After oral administration of 20mg/kg, the maximum blood level of radioactirity was reached at 4.0hr in female rats. The blood level of radioactivity-time profiles in male and female rats were similar, and the absorptionof $^{14}C$-YH1885 was not affected by food. 3. Appproximately 89% and 1% of radioactivity of the total dose were excreted in feces and urine, respectively. 4. Biliary excretion of radioactivity was 47.9% of the dose. Enterohepatic circulation of radioactivity was 49.6%. 5. Radioactivity was excreted maily into feces via bile. 6. The concentration of radioactivity in most tissues reached the peak level at 4.0hr after dosing, and then declined. Autoradiograms of male rats showed that the radioactivity levlels in the fat, harder's gland, liver and G-Itract were higher than those in the other tissues and the elimination of radioactivity from fat and liver was slow. 7. Autoradiograms of a pregnant rat showed that radioactivity was transferred to mammary gland, placenta and fetus. The radioactivity level in the mammary gland was higher than that in the blood.
