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Acta Endocrinol (Copenh). 1980 Mar;93(3):375-9.

Metabolism of a new synthetic progestagen, Org 2969, in female volunteers. The distribution and excretion of radioactivity after an oral dose of the labelled drug.

Abstract

The metabolism of a new synthetic progestagen, Org 2969 was studied in 4 healthy female volunteers. During the first part of the study (Phase I), the volunteers ingested 50 microgram (about 0.1 mCi) of [16-3H5Org 2969 together with 50 microgram of ethinyloestradiol as a single dose. During the second part of the study (Phase II), a 10-day pre-treatment with the same dosage of non-radioactive compound preceded the administration of the radioactive steroid. A peak level of total radioactivity, representing 3.16-5.02% of the dose given/l of serum, was achieved within 2-3 h in Phase I. During Phase II, the corresponding figures were 4.54-5.13% after 1.5-3 h. The difference was mainly due to an increase of freely-extractable steroids during Phase II. The difference can at least partly be explained by assuming a change in the kinetics of the metabolism of Org 2969 by pre-treatment with Org 2969 and ethinyloestradiol. The mean recovery of radio activity in urine and faeces was 83.0%/48.1%/34.9% (total/urine/faeces) of the total dose in Phase I and 76.1%/45.2%/30.9% during Phase II. The differences in the total excretion and in the radioactivity excreted in the faeces were significant.

PIP:

Org 2969, a newly synthesized progestin from the laboratory of Organon Int B.V., Oss, the Netherlands, was ingested by women volunteers in an oral, radioactive dose to learn more about the drug's metabolism in humans. 4 female volunteeers were studied. The study was conducted in 2 phases, the first had volunteers ingesting about .1 mCi (50 mcg) of tritiated Org 2969 along with 50 mg of ethinylestradiol (as a single dose), and the second phase was a 10-day treatment with the same (50 mcg) dose of Org 2969 without radiolabel followed by administration of tritiated Org 2969. In Phase 1, peak level of total radioactivity occurred within 2-3 hours; this peak represented 3.16-5.02% of the dose administered per liter of serum. The corresponding figures for Phase 2 were 1.5-3 hours and 4.54-5.13%. Phase 2 samples had increased levels of freely-extractable steroids compared with Phase 1, which explains the difference in measurements. Another aspect of the difference in metabolism of the 2 doses must result from a change in kinetics of the metabolism of Org 2969 by pretreatment with Org 2969 (Phase 2) or simultaneous administration with ethinylestradiol (Phase 1). 1 level was significantly different between Phase 1 and 2 and that was amount of drug excreted in feces. In Phase 1, mean recoveries of radioactivity in urine and feces were 83%/48.1%/34.9% (total/urine/feces) and for Phase 2 the same recoveries were 76.1%/45.2%/30.9%.

PMID:
7376796
[Indexed for MEDLINE]

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