The in vivo metabolism of Althesin (alphaxalone + alphadolone acetate) in man

Gas chromatograph-mass spectrometry has been used to study the metabolism of Althesin (alphaxalone and alphadolone acetate) in man. Two metabolites, 20 alpha-reduced alphaxalone and alphadolone, as well as the two parent steroids, have been detected in the plasma during and after an infusion of Althesin. The main urinary metabolites were alphaxalone and 20 alpha-reduced alphaxalone, with smaller amounts of alphadolone, all of which were excreted mainly as the glucuronide conjugates. No alphadolone acetate was detected in the urine. In 3 patients in whom bile was collected over the 1st 24 h post-operation from an indwelling T-tube, it has not been possible using the methods described to detect in bile the presence of the parent steroids, or any of their probable metabolites.