Single dose pharmacokinetics of 5 formulations of lithium: a controlled comparison in healthy subjects

The single dose pharmacokinetics of 4 lithium preparations (Camcolit-400, Priadel, Liskonum, Litarex) and a new micro-encapsulated formulation were compared in normal volunteers using a balanced cross-over design. The data show an inverse relationship between rate of release and bioavailability. The pharmacokinetic characteristics of Camcolit-400 and Priadel were similar; both showed earlier and greater peak serum concentrations than the other 3. The new formulation, which accounted for most of the significant variance, had the slowest rate of release and the lowest bioavailability. Statistical analysis showed significant differences between the 5 preparations for C-max, T-max, 12-h serum levels, AUC and urinary excretion, but not for the 24-h serum levels. No serious untoward side-effects were noted.