Absorption of sustained-release and plain papaverine in man.

The concentrations of papaverine in the plasma of healthy volunteers were determined by a GLC-method both after single and repeated oral doses of plain and sustained-release drug formulation. In both experiments the AUC-value after the sustained-release drug form was significantly lower than after the plain papaverine and no maintenance of plasma levels for 12 hours after the sustained-release drug form was observed. Our work demonstrates that the systemic availability or papaverine can be markedly affected by product formulation.