A COMPARATIVE STUDY ON HYPNOTICS OF THE BARBITURIC ACID SERIES

The extensive use of barbital as a hypnotic since its introduc-tion by Fischer and Von Mering (1) in 1904 has stimulated the investigation of other barbituric acid derivatives. As a result a number of new synthetics of this series have been prepared; several have been studied pharmacologically; some have already appeared on the market as substitutes for barbital. The present investigation was made upon the suggestion of Dr. E. H. Voiwiler who, with the main purpose in view of in-. vestigating the allyl barbituric acids, prepared a series of bar-bituric acid derivatives for comparison with barbital and other newer barbituric acid hypnotics of promising character. The relative toxicity and efficiency of these hypnotics were determined on one and the same species of animal under identical conditions, according to the methods described later. The margin between the toxicity (minimum fatal dose) and the efficiency (minimum effective dose), of each hypnotic, expressed in percentage of the minimum fatal dose, was chosen as an index for its safety. It is understood that the safety margin for albino rats may or may not correspond to that for the human. The following is a list of the hypnotics: Diethyl barbituric acid (Barbital) Isopropyl ethyl barbituric acid n-Butyl ethyl barbituric acid (Neonal) Isoamyl ethyl barbituric acid (Amytal) Phenyl ethyl barbituric acid (Luxninal) Benzyl ethyl barbituric acid n-Butyl isopropyl barbituric aci