Effect of aluminum phosphate on the bioavailability of ranitidine

The effect of aluminum phosphate on the bioavailability of ranitidine has been investigated in 10 young, healthy volunteers. Following a random cross over design, each subject took at a 1 week interval 150 mg ranitidine alone or with 11 g aluminum phosphate. Plasma and urine ranitidine levels were measured by HPLC. The antacid reduced both the maximum plasma ranitidine concentration by 40% and the area under the curve by 30%. Elimination of ranitidine was not changed. The results indicate that aluminum phosphate significantly diminished the bioavailability of ranitidine.