The adsorption of quinine and quinidine to activated charcoal with and without magnesium sulfate

The effect of magnesium sulfate on the in vitro adsorption of quinine and quinidine to activated charcoal (AC) was studied. Solutions of quinine and quinidine were prepared at concentrations of 5 and 10 micrograms/ml and at simulated toxic concentrations of 62.5, 125 and 250 micrograms/ml in distilled water. Drug-charcoal slurries were vortex mixed, centrifuged and analysed for free drug in the supernatant. Quinine had adsorption capacities of 78.2 to 100% with 12.5 or 50 mg AC; 12.5 or 50 mg AC adsorbed 29.5-87.2% of the quinidine. Quinine (250 micrograms/ml) had adsorption capacities of 0.0, 21.1, 52.4, 78.3 or 93.8% to 12.5, 50, 125, 250 or 500 mg AC, respectively. There was a corresponding increase quinine and quinidine adsorption at increasing concentrations of AC. The adsorption of quinine and quinidine seemed dose dependent. Magnesium sulfate (7.5 mg/ml) enhanced the adsorption of quinine to AC, but increased the amount of AC required for quinidine-charcoal adsorption.