To investigate the pharmacokinetic effect of a vaginally administered antimycotic (miconazole), antibiotic (clindamycin), spermicide (nonoxynol-9) or the concomitant use of tampons during the use of an intravaginal ring releasing anastrozole and levonorgestrel

Inclusion Criteria:

• Healthy pre-menopausal female subject.
• Age: 18 - 50 years (inclusive) at the first screening visit. For the subject > 45 years follicle stimulating hormone (FSH) will be investigated at the second screening visit to confirm the pre-menopausal status (FSH < 40 IU/L in serum).
• Body mass index (BMI ) above or equal 18, and below or equal 30 kg / m² at the first screening visit.
• Adequate venous access.
• Ability to understand and follow study-related instructions
• Agreement to use adequate non-hormonal contraception.
• Confirmation of the subject's health insurance coverage prior to the first screening examination/visit.

Exclusion Criteria:

• Incompletely cured pre-existing diseases for which it can be assumed that the absorption, distribution, metabolism, elimination and effects of the study drugs will not be normal.
• Thrombophlebitis, venous / arterial thromboembolic diseases (particularly deep vein thrombosis, pulmonary embolism, stroke, myocardial infarction).
• Presence or history of prodromata of thrombosis (e.g. transient ischemic attack, angina pectoris).
• Known hypersensitivity to the study medications (active substances or excipients of the preparations).
• Regular intake of medication other than hormonal contraceptives.
• Use of systemic or topical medication or substances which oppose the study objectives or which might influence them within 4 weeks before first administration of the study medication,
• Smoking of more than 10 cigarettes daily; if the subject is a smoker: subject is older than 35 years
• Suspicion of or known current drug, medicine or alcohol abuse (including anabolics, high-dose vitamins).
• Abnormal cervical smear
• Previous ectopic pregnancy.