Distribution and elimination of RGH-5002 in rats.

In the present study distribution and elimination of RGH-5002--a new centrally acting muscle relaxant--were investigated in rats by using 14C-labelled compound. Whole-body autoradiography and quantitative determination of the radioactivity in various organs following single and repeated oral administration of [14C]RGH-5002 demonstrated extensive distribution of the drug with high levels in the gastrointestinal tract, kidneys, liver, endocrine and exocrine glands and lungs. Minimal accumulation was observed after repeated (8 days) administration. The same distribution characteristics were observed in both sexes. In pregnant rats radioactivity appeared in the placenta and fetal tissues. Elimination was investigated by measuring radioactivity in 24 h fractions of urine and faeces after single dose administration of the drug. The larger portion of radioactivity was excreted in the urine (81.67 +/- 1.61% of the dose). The faecal recovery was 11.12 +/- 1.19% of the administered dose. Approximately 80% of the excreted radioactivity was recovered within the first 24 hours.