Bioavailability and pharmacokinetics of a new, slow-release potassium chloride capsule

The bioavailability of a new, slow-release potassium chloride product consisting of coated beads in a hard gelatin capsule was compared with the bioavailability of two marketed products, an elixir and a slow-release tablet, by determining the urinary excretion of potassium. Twelve healthy male volunteers were dosed with a total of 80 mEq of potassium, in a single dose for the capsule and tablet and in three 26.6-mEq doses at 6-hr intervals for the elixir. Mean recoveries in 24-hr urine potassium levels from all three dosage forms after subtracting normal urine potassium excretion levels were 50.8% from the capsule, 53.9% from the elixir, and 63.1% from the tablet. Maximum excretion rates were reached at 2.0 hr for the elixir, 6.8 hr for the capsule, and 4.0 hr for the tablet. Fewer side effects were reported with the capsule than with the elixir and tablet.