Assessment of the pharmacodynamic profile of the drug Ciclo 21 ®, marketed by União Química Farmacêutica Nacional S / A, compared to the drug Nordette ® Laboratory Wyeth Pharmaceutical Ltda. Through the modulation of hormonal response (inhibition of the pituitary) evidenced by measurement serum LH and FSH for 28 days, as well as by the absence of follicle formation demonstrated by transvaginal ultrasound examinations

secondary objective

• Evaluation of the safety aspects of medicines such as type, frequency and intensity of adverse events between groups during the 28 day trial.

exploratory objective

• Evaluation of the pharmacokinetics of the drug administered through the dosage of serum hormone levonorgestrel and ethinyl estradiol for 28 days.

Inclusion Criteria:

1. Comply with all study procedures, sign, initial and date back, of their own free will, the IC;
2. Women aged between 18 and 35 years, regardless of race and class;
3. Make use of safe non-hormonal method of contraception such as tubal ligation, non-hormonal IUDs or condoms, or be hysterectomised or be vasectomized sexual partner;
4. Examination of Beta-HCG negative;
5. with regular menstrual cycles every 24 to 32 days, at least the last three months;
6. present normal Pap test (current or during the past 02 years);
7. Present or vaginal examination found that the changes do not interfere in the study;
8. present levels of FSH, LH, estradiol and TT for the normal menstrual cycle, as well as normal transvaginal sonographic reports.

Exclusion Criteria:

1. Provide a contraindication to the use of steroids;
2. Use regular or prediction of drugs that interfere with the metabolism of the investigational products, such as antibiotics, anticonvulsants, anticoagulants and hypoglycemic drugs;
3. smokers or have stopped smoking less than 12 months;
4. Diabetic;
5. Toxic-dependent;
6. BMI <18 and> 25;
7. have made use of topical or systemic sex hormone for at least two months before the start of the study;
8. Background and personal or family history of thrombosis or bleeding disorders or vascular disorders or cardiovascular disease;
9. Laboratory tests, gynecological ultrasound or changed, the medical criteria;
10. Individuals with allergies or rheumatic diseases for which is indicated the use of cortico-steroid medication;
11. carry any endocrine changes, especially pituitary and gonadal and / or who are advised to use hormones;
12. with lesions or abnormalities suspected or confirmed in the gonads.
13. personal or family history of breast cancer or other hormone-dependent breast pathology;
14. with hypertension or diabetes mellitus (for drug interactions between the COC and hypoglycemic agents and antihypertensives);

a) History of nausea with oral use of COCs; p) Any condition that may interfere with the discretion of the investigator in the study data as well as being the measurement of the study be deleterious to the patient.

The study data will be maked available after journal's approbation. The manuscript contained all of data it has been submitted.