Influence of Silexan on pharmacokinetics and hormonal activity in females taking oral contraceptives

INTERVENTION: One capsule with 160 mg Silexan or placebo respectively per day in the morning for 2 times 28 days (56 consecutive days). CONDITION: Pharmacokinetics of ethinyl estradiol and levonorgestrel ; Not Applicable PRIMARY OUTCOME: Plasma levonorgestrel and ethinyl estradiol: AUCtau, at the PK profile days over 24 hours at day 19, 20 or 21 of the cycle. SECONDARY OUTCOME: 1. Hoogland score assessments at day 28 of the cycle; 2. Cmax and tmax of levonorgestrel and ethinyl estradiol profiles, assessed over 24 hours at day 19, 20 or 21 of the cycle; 3. Safety and tolerability INCLUSION CRITERIA: 1. Aged 18 ‐ 38 years 2. Signed informed consent 3. Healthy female volunteer 4. Body mass index between 18 and 30 kg/m^2 5. At least 3 months since delivery, abortion, or lactation before randomisation 6. Willingness to use non‐hormonal methods of contraception 7. Subjects must have taken oral contraceptive for at least two cycles before start of the first treatment cycle