Antihypoxic effect of the hydroxylamine derivative HB-7

The antihypoxic effect of the newly-synthesized hydroxylamine barbiturate HB-7, compared with the effects of phenobarbital and pentobarbital, was studied in experiments on albino mice, using the following models of hypoxia: hypobaric, anoxic, asphyctic and haemic. A dose-effect dependence was established when the survival of the mice was prolonged under the effects of the barbiturates tested, applying the asphyctic and haemic hypoxy tests. The latter two tests were also used to determine the average effective doses (ED60) of the barbiturates. HB-7 was superior in its action to phenobarbital and pentobarbital, manifesting higher protective indices (PI-LD50: ED50): for HB-7 PI is 4.2, for phenobarbital--3.2 and for pentobarbital--2.5, using the haemic hypoxy test. It is concluded that HB-7, i.e. 2-hydroxylamine-5-ethyl-5-sec, pentylbarbituric acid, manifests a marked protective effect in the hypoxy tests used, exceeding in some cases the effects of phenobarbital and pentobarbital.