To further elucidate the distribution and differentiation of mofebutazone in comparison to phenylbutazone, 6 rats received 200 mg/kg 4-14C-mofebutazone corresponding to approx. 27 microCi/animal. 2 animals were sacrificed each time after 45 min, 6 h and 24 h. The 4-14C-plasma level was determined at the corresponding test periods and the radioactivity eliminated within 24 h in the urine was also determined. In addition autoradiograms of the whole animal were prepared for each animal. According to this study 4-14C-mofebutazone is distributed mainly in the metabolisation and elimination organs, a moderate activity was to be found under the skin and muscle tissue, but none, however, in the central nervous system and the bone marrow. Nearly 81% of the substance was eliminated after 24 h and with exception the colon the corresponding autoradiograms were practically free of activity. Because of the short half-life time and the rapid elimination mofebutazone does not lead to any accumulation.

Animals↗

PubMedDate not supplied

[Pharmacology, toxicology and pharmacokinetics of mofebutazone].

The difference between mofebutazone and phenylbutazone is shown by means of toxicological, pharmacological and pharmacokinetic studies as well as by the protein binding. In spite of a certain chemical similarity both substances differ distinctly. Mofebutazone is approx. 5-6 times less toxic than phenylbutazone but its analgesic and antiphlogistic effects are weaker than those of phenylbutazone. The half life time of mofebutazone of 1.9 h is considerably shorter than that of phenylbutazone (54-99 h). Mofebutazone, in contrast to phenylbutazone, is mainly glucuronidised and to 94% eliminated within 24 h, phenylbutazone on the other hand to only 88% within 21 days. In spite of a high plasma protein binding quota of 99%, mofebutazone is classed among those substances with a medium binding potential. Conclusions may only be drawn with great reservation with regard to a category of substances from the effect and side effects of one substance on the basis of the present studies.

Adult↗