Pharmacokinetic Study of Zeolite A, Sodium Aluminosilicate, Magnesium Silicate, and Aluminum Hydroxide in Dogs

Abstract

Zeolite A is a synthetic zeolite which may have therapeutic utility in osteoporotic individuals because of its ability to stimulate bone formation. A study of Zeolite A (30 mg/kg), sodium aluminosilicate (16 mg/kg), magnesium trisilicate (20 mg/kg), and aluminum hydroxide (675 mg) was designed in beagle dogs. The purpose of this study was to compare the oral bioavailability of silicon and aluminum from Zeolite A, sodium aluminosilicate, magnesium trisilicate, and aluminum hydroxide in dogs. Twelve female dogs received each compound as a single dose separated by one week in a randomized, 4-way, crossover design. Plasma samples were drawn at time 0 and for 24 hours after dosing. The concentrations of silicon and aluminum were determined by graphite furnace atomic absorption. The mean plasma silicon AUC values (±S.D.) were 9.5 ± 4.5, 7.7 ± 1.6, 8.8 ± 3.0, 6.1 ± 1.9 mg · hr/L and the mean plasma silicon Cmax values (±S.D.) were 1.07 ± 1.06, 0.67 ± 0.27, 0.75 ± 0.31, 0.44 ± 0.17 mg/L for Zeolite A, sodium aluminosilicate, magnesium trisilicate, and aluminum hydroxide respectively. Although mean silicon AUC and Cmax values were elevated when compared to baseline after administration of the silicon containing compounds, only the AUC from Zeolite A reached statistical significance (p = 0.041). The mean plasma silicon Tmaxvalues (±S.D.) were 7.9 ± 6.4, 5.8 ± 4.6, 6.9 ± 6.3 and 8.5 ± 3.4 hrs for Zeolite A, sodium aluminosilicate, magnesium trisilicate and aluminum hydroxide respectively. These values were not statistically different. The mean plasma aluminum AUC values for Zeolite A, sodium aluminosilicate, magnesium trisilicate and aluminum hydroxide (±S.D.) were 342 ± 111, 338 ± 167, 315 ± 69, 355 ± 150 µg · hr/L and the mean aluminum Cmax values (±S.D.) were 29 ± 9, 27 ± 14, 24 ± 5 µg/L, 29 ± 11 respectively. The plasma aluminum Tmax values (±S.D.) were 3.5 ± 4.1, 4.2 ± 4.3, 5.7 ± 7.3 and 5.0 ± 4.7 hrs for Zeolite A, sodium aluminosilicate, magnesium trisilicate, and aluminum hydroxide respectively. There was no statistically significant absorption of aluminum from the aluminum containing treatments. © 1995, Plenum Publishing Corporation. All rights reserved.