Effect of Three Multiple-dose Regimens of BIA 9 1067 at Steady-state on the Levodopa Pharmacokinetics

Inclusion Criteria: * able to participate and willing to give written informed consent; * male and female subjects; * aged 18 to 45 years, inclusive; * body mass index (BMI) between 18 and 30 kg/m2; * healthy as determined by the Investigator on the basis of medical history, physical examination, clinical laboratory test results, vital signs, complete neurological examination and 12-lead electrocardiogram (ECG); * negative tests for hepatitis B surface (HBs) antigen, anti-hepatitis C virus (HCV), human immunodeficiency virus-1 (HIV-1) and HIV-2 antibodies at screening; * negative screen for drugs of abuse and alcohol at screening and admission to the treatment period; * non-smokers or ex-smokers for at least 3 months; * if sexually active, agreed to use a medically acceptable form of contraception throughout the study; * if female of childbearing potential, had a negative human chorionic gonadotropin (HCG) beta serum pregnancy test at screening and admission to the treatment period. Exclusion Criteria: * who did not conform to the above inclusion criteria, or in case of volunteers who had a clinically relevant surgical history, a clinically relevant family history; or who had a history of relevant atopy; * who had a significant infection or known inflammatory process at screening or admission to the treatment period; acute gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea, heartburn) at the time of screening or admission to the treatment period; * who were vegetarians, vegans or had medical dietary restrictions; * who could not communicate reliably with the Investigator; * who were unlikely to co-operate with the requirements of the study; history of hypersensitivity to BIA 9 1067, tolcapone, entacapone, levodopa, carbidopa, benserazide or any related products (including excipients of the formulations) as well as severe hypersensitivity reactions (like angioedema) to any drugs; * any significant cardiovascular (e.g. hypertension), hepatic, renal, respiratory (e.g. childhood asthma), gastrointestinal, endocrine (e.g. diabetes, dyslipidemia), immunologic, dermatological, haematological, neurologic, or psychiatric disease; * any clinically significant illness in the previous 28 days before day 1 of this study; history of drug abuse within 1 year before study day 1; history of alcoholism within 1 year before day 1. * Consumption of more than 50 g of ethanol per day (12.5 cL glass of 10° \[10%\] wine = 12 g; 4 cL of aperitif, 42° \[42%\] whiskey = 17 g; 25 cL glass of 3° \[3%\] beer = 7.5 g; 25 cL glass of 6° \[6%\] beer = 15 g); * poor motivation, intellectual problems likely to limit the validity of consent to participate in the study or limit the ability to comply with the protocol requirements or inability to cooperate adequately, inability to understand and to observe the instructions of the physician; * donation of blood (i.e., 450 mL) within 60 days before study day 1; * positive urine screening of ethyl alcohol or drugs of abuse upon admission to the treatment period; * any history of tuberculosis and/or prophylaxis for tuberculosis; positive results to HIV, hepatitis B surface antigen (HBsAg) or anti-HCV tests; * participation in any previous clinical study with BIA 9 1067; * if female, being pregnant or breast-feeding.