ACTION OF CENTRAL NERVOUS SYSTEM STIMULANT AND DEPRESSANT DRUGS IN INTACT ANIMAL .4. SURFACE ACTIVITY OF DRUGS WITH CENTRAL STIMULANT DEPRESSANT, OR DUAL STIMULANT-DEPRESSANT ACTION

Air-solution surface tension isotherms have been determined for selected drugs with CNS stimulant action (bemegride, diethadione, pentylenetetrazol, picrotoxin and β-spirocyclopentaneglutarimide), depressant action (amylobarbitone sodium, hydroxydione, β-methyl-β-n-amylglutarimide, β-methyl-β-n-butylglutarimide, pentobarbitone sodium and trimethadione) or dual stimulant-depressant action (β-methyl-β-n-propylglutarimide, sodium 5,5-dipenylhydantoinate (Dilantin) and sodium 5-ethyl-5-(1,3-dimethylbutyl)barbiturate). The stimulant drugs tend to populate the aqueous bulk phase while the depressant drugs tend to accumulate at the air-solution interface. The surface activities of the drugs with dual central action appear to be related to the depressant activities of these substances. Thus, a general trend has been found for this limited series of drugs suggesting a possible correlation between their surface activities and pharmacological effects; a hypothesis of drug action which is consistent with such a correlation has been discussed. © 1969.