Further studies of the relative rates of absorption of drugs from the lymph sac and the muscles of the frog

Abstract

Previously it has been shown that members of the digitalis group as measured by their intensity of action upon the heart, are absorbed more rapidly and evenly from intramuscular injections than from the lymph sac. Strychnine was also found to be more rapidly absorbed from the muscles. These facts led us to suggest that in the official assay of the digitalis group of drugs the substitution of intramuscular injections be made. The present paper deals with further studies of this question.

Epinephrin has been chosen for study because of the readily measurable changes it induces in the diameter of the frog's pupil. The time from injection of the drug to beginning dilatation has been designated as the latent period and has been made the basis of comparison of the rates of absorption by the two methods. As the tables and curves (Figures I and II) show the latent period after intramuscular injection is always shorter. It is felt that this finding further substantiates the above results.