BIOAVAILABILITY OF SILICON AND ALUMINUM FROM ZEOLITE-A IN DOGS

A study in beagle dogs was carried out to estimate the bioavailability of silicon and aluminum from Zeolite A administered as a capsule, ora l suspension, and oral solution relative to an intravenous bolus infus ion (i.v.) administered over a 1-1.5 min interval; Twelve dogs receive d single doses of Zeolite A after a 1 week control period ina randomiz ed five-way crossover design. Plasma samples were drawn at time 0 and for 36 h after dosing. The concentrations of silicon and aluminum were determined by graphite furnace atomic absorption at the University of North Carolina School of Medicine (Bioanalytical Laboratory, UNC). Th e plasma silicon and aluminum data from i.v. infusion were best descri bed by two-compartment and three-compartment: open models, respectivel y. The mean elimination half-life and clearance of silicon from the i. v. dose were 17.5 h and 0.221 +/- 0.0192 ml/min per kg. The mean exten t of absorption of silicon from the oral capsule, oral solution and or al suspension was 2.33%, 3.44% and 2.73%, respectively, relative to th e intravenous bolus. The mean elimination half-life and clearance of a luminum were 91.2 h and 0.0497 +/- 0.0082 ml/min per kg. The extent of absorption of aluminum from the oral dosage forms was less than 0.1%, relative to the intravenous infusion. The plasma aluminum AUC values from the oral capsule and suspension showed no statistical difference from those during the control period, but the aluminum AUC of the oral solution was statistically greater than the AUC of the corresponding control period.