Effect of Paracetamol on Opicapone Pharmacokinetics in Healthy Volunteers

Inclusion Criteria: * Subjects who are able and willing to give written informed consent. * Male or female subjects aged between 18 and 45 years, inclusive. * Subjects of body mass index (BMI) between 19.0 and 30.0 kg/m2, inclusive. * Subjects who are healthy as determined by pre-study medical history, physical examination, vital signs, complete neurological examination and 12-lead ECG. * Subjects who have negative tests for HBsAg, anti-HCVAb and HIV-1 and HIV-2 Ab at screening. * Subjects who have clinical laboratory test results clinically acceptable at screening and admission to each treatment period. * Subjects who have a negative screen for alcohol and drugs of abuse at screening and admission to each treatment period. * Subjects who are non-smokers or ex-smokers for at least 3 months. * (If female) She is not of childbearing potential by reason of surgery or, if of childbearing potential, she uses an effective non-hormonal method of contraception (intrauterine device or intrauterine system; condom or occlusive cap \[diaphragm or cervical or vault caps\] with spermicidal foam or gel or film or cream or suppository; true abstinence; or vasectomized male partner, provided that he is the sole partner of that subject) for all the duration of the study. * (If female) She has a negative serum pregnancy test at screening and a negative urine pregnancy test on Day -1 of each treatment period. Exclusion Criteria: * Subjects who have a clinically relevant history or presence of respiratory, gastrointestinal, renal, hepatic, haematological, lymphatic, neurological, cardiovascular, psychiatric, musculoskeletal, genitourinary, immunological, dermatological, endocrine, connective tissue diseases or disorders. * Subjects who have a clinically relevant surgical history. * Subjects who have any clinically relevant abnormality in the coagulation tests. * Subjects who have any clinically relevant abnormality in the liver function tests (a case-by-case decision for any abnormality must be discussed with the Sponsor before inclusion). * Subjects who have a history of relevant atopy or drug hypersensitivity, particularly to paracetamol or any COMT inhibitor. * Subjects who have a history of alcoholism or drug abuse. * Subjects who consume more than 14 units of alcohol a week. * Subjects who have a significant infection or known inflammatory process at screening or admission to each treatment period. * Subjects who have acute gastrointestinal symptoms (e.g., nausea, vomiting, diarrhoea, heartburn) at the time of screening or admission to each treatment period. * Subjects who have received paracetamol within 2 weeks of admission to the first period. * Subjects who have used any other medicines within 2 weeks of admission to first period that may affect the safety or other study assessments, in the investigator's opinion. * Subjects who have previously received OPC. * Subjects who have used any investigational drug or participated in any clinical trial within 90 days prior to screening. * Subjects who have participated in more than 2 clinical trials within the 12 months prior to screening. * Subjects who have donated or received any blood or blood products within the 3 months prior to screening. * Subjects who are vegetarians, vegans or have medical dietary restrictions. * Subjects who cannot communicate reliably with the investigator. * Subjects who are unlikely to co-operate with the requirements of the study. * Subjects who are unwilling or unable to give written informed consent. * (If female) She is pregnant or breast-feeding. * (If female) She is of childbearing potential and she does not use an approved effective contraceptive method or she uses oral contraceptives.