Centrally acting muscle relaxant properties of
AD-2239 were compared with those of
tolperisone,
eperisone,
diazepam and
baclofen.
AD-2239 dose-relatedly depressed extensor reflex in
urethane-
chloralose anesthetized intact and spinal rats, the i.v. potencies being similar to those of
tolperisone and
eperisone. These effects of
AD-2239 were long-lasting. When orally administered,
AD-2239 was 4 times more potent than
eperisone.
Diazepam was without effect on the extensor reflex in spinal rats.
AD-2239 depressed the flexor reflex without affecting the patellar reflex in anesthetized cats.
Baclofen depressed the latter. When orally administered,
AD-2239, in a dose-related manner, depressed the flexor reflex in anesthetized cats, with a potency approximately 8 times that of
tolperisone or
eperisone.
AD-2239 produced a dose-related reduction of anemic
decerebrate rigidity (alpha-rigidity) in rats. The potency, at the minimum effective i.v. dose, was 4 times greater than that of
tolperisone or
eperisone, equal to that of
diazepam, and one-half of that of
baclofen.
AD-2239 neither affected spontaneous electroencephalogram (EEG) nor EEG arousal response in immobilized cats, while the other drugs, at comparatively low doses, depressed them. The results strongly suggest that
AD-2239 may have advantages over the existing
centrally acting muscle relaxants in the treatment of human clinical spasticity and
muscle spasm syndromes.