Dose-Finding Study of PDC31 in Patients With Primary Dysmenorrhea

Inclusion Criteria: * Otherwise healthy females with a history of primary dysmenorrhea * Using effective birth control excluding intrauterine contraceptive device (IUCD) * Must be 18 years of age or older * Must give written informed consent to participate in this study Exclusion Criteria: * Patients with an intrauterine contraceptive device or using oral contraceptives within 3 months of treatment in this study * Patients with confirmed pelvic inflammatory disease, endometriosis or adenomyosis * Patients who are pregnant or who test positive at baseline or are at risk of becoming pregnant while on study * Patients who are breastfeeding * Patients with hepatic or renal function tests greater than the upper limit of normal and deemed clinically significant by the Investigator at screening * Patients with a clinically significant medical or psychiatric disorder or a serious medical conditions within the past 6 months which in the opinion of the investigator, should prohibit participation in this study * Patients who have been exposure to any investigational drug within 4 weeks prior to screening