[Release of norfenefrine from sustained-release formulations by an in vitro dissolution model. Simulation of "drug levels" by calculation using pharmacokinetical constants and comparison with in vivo course of action (author's transl)].

Drug release and dissolution behaviour of 1-(3'-hydroxyphenyl)-2-amino-ethan-1-ol hydrochloride (norfenefrine-HCl) from a sustained-release norfenefrine preparation (Esbuphon) were tested by an in vitro dissolution model in comparison with other norfenefrine formulations. By using pharmacokinetical constants, relative "drug levels" were calculated and compared with the activity curves from animal experiments. Conformities in time course were shown. Variations are discussed. The application of the model is justified if determination of serum concentration of norfenefrine cannot be done.