Relative to phenazepam, 3-hydroxyphenazepam has diminished myorelaxant properties, but is about equivalent in most other regards. Also 3-hydroxyphenazepam behaves as a positive allosteric modulator of the benzodiazepine site of the GABAA receptor with an EC50 value. There are significant differences in the rate of phenazepam metabolism in different species, so that 3-hydroxy phenazepam can be detected shortly after oral administration of the parent compound in cats, rats, and dogs but not in humans. The physiological and toxicological properties of this compound are not known. This product is a qualified Reference Material (RM) that has been manufactured and tested to meet ISO17025 and Guide 34 guidelines.