The pharmacokinetic assessment of sodium cromoglycate

Abstract

The plasma concentration of sodium cromoglycate (SCG) was measured in four healthy subjects by radioimmunoassay after a 4 mg intravenous dose and after inhaling from 20 mg capsules, and from 10 and 30 mg ml−1 nebulizer solutions. The mean absorption constant (K1) after inhalation was 0·43 h−1. The mean elimination constant from the plasma (Kelim) after intravenous administration was 11·5 h−1, and that after inhalation was similar. The apparent volume of distribution of SCG (Vdβ) was 0·2 litre kg−1 and the mean plasma clearance was 0·35 litre h−1kg−1. The amount of SCG absorbed after inhalation varied according to the method of inhalation and dose. After the inhalation of powder from 20 mg capsules, 1·30–3·96 mg reached the plasma, after inhalation of SCG produced by nebulizing a 10 mg ml−1 solution for 5 min at 10 psi using a Minineb nebulizer 0·19—0·31 mg reached the plasma and when the solution was increased to 30 mg ml−1 the figure was 0·33—0·45 mg.