Pharmacokinetics of ambenonium, a reversible cholinesterase inhibitor, in rats

The pharmacokinetics of ambenonium, a reversible cholinesterase inhibitor, in rats was investigated following intravenous administration of the drug. Mean residence time and steady state volume of distribution were 23–36 min and 0·20–0·311 kg−1, respectively, and were dose independent at the dose of 0·3–3 μmole kg−1. Total body clearance of 8·2 ml min−1 kg−1 over 0·3 μmole kg−1 was slightly increased to 11·3 ml min−1 kg−1 at 3 μmole kg−1. Renal clearance was also increased with the increase of the dose, while hepatobiliary clearance was substantially constant. Ambenonium was highly concentrated in the liver, kidney, spleen, and lung. About 30 per cent of the dose is concentrically stored in the liver at 6 h after administration, and had not disappeared after 24 h.