Systemic availability of levonorgestrel after single oral administration of a norgestimate-containing combination oral contraceptive to 12 young women.
Contraception
; 49(3): 255-63, 1994 Mar.
Article
em En
| MEDLINE
| ID: mdl-8200219
ABSTRACT
Norgestimate is a novel progestin which undergoes both in vivo and in vitro metabolic conversions to a number of metabolites, of which the most important are levonorgestrel acetate, levonorgestrel oxime and levonorgestrel itself. It has been claimed that the progestogenic activity of norgestimate in clinical studies is almost exclusively based on the parent drug and its major metabolite, levonorgestrel oxime, and that levonorgestrel does not make an important contribution. However, to date, no data on the presence of levonorgestrel in the serum of women who have received oral doses of norgestimate have been presented. In the present study, 12 young female volunteers received single oral doses of 250 micrograms levonorgestrel in combination with 50 micrograms ethinylestradiol and 250 micrograms norgestimate in combination with 35 micrograms ethinylestradiol in an open, randomized, intraindividual comparison. Blood samples were taken at regular time intervals after each treatment, and the serum samples were analyzed for their content of levonorgestrel. Basic pharmacokinetic parameters of levonorgestrel were calculated and from the ratio of the AUC values obtained after both administrations, the bioavailability of norgestimate-derived levonorgestrel was calculated. About 22 +/- 6% of the dose of norgestimate administered became systemically available as levonorgestrel. Thus, it was concluded that levonorgestrel is a major metabolite of orally administered norgestimate, and that at least part of the pharmacologic activity of norgestimate in women is due to the presence of levonorgestrel.
Palavras-chave
Clinical Research; Contraception; Contraception Research; Contraceptive Agents; Contraceptive Agents, Estrogen; Contraceptive Agents, Female; Contraceptive Agents, Progestin; Contraceptive Methods--administraction and dosage; Ethinyl Estradiol; Examinations And Diagnoses; Family Planning; Human Volunteers--women; Laboratory Examinations And Diagnoses; Levonorgestrel; Norgestimate; Oral Contraceptives, Combined--administraction and dosage; Oral Contraceptives--administraction and dosage; Research Report
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Levanogestrel
/
Anticoncepcionais Orais Combinados
/
Etinilestradiol
/
Norgestrel
Tipo de estudo:
Clinical_trials
Limite:
Adolescent
/
Adult
/
Female
/
Humans
Idioma:
En
Revista:
Contraception
Ano de publicação:
1994
Tipo de documento:
Article
País de afiliação:
Alemanha