Pharmacokinetic-Pharmacodynamic Interaction Between Four Different Single Doses of BIA 3-202 and a Single Dose of Levodopa/Carbidopa (100/25 mg)

Inclusion Criteria: * Male and female subjects aged between 18 and 45 years, inclusive. * Subjects of body mass index (BMI) between 19 and 28 kg/m2, inclusive. * Subjects who were healthy as determined by pre study medical history, physical examination, and 12- lead ECG. * Subjects who had clinical laboratory tests acceptable to the investigator. * Subjects who were negative for HBsAg, anti-HCV Ab and HIV-1 and HIV-2 Ab tests at screening. * Subjects who were negative for drugs of abuse at screening and admission. * Subjects who were non-smokers or who smoked less than 10 cigarettes or equivalent per day. * Subjects who were able and willing to give written informed consent. * (If a woman) She was not of childbearing potential by reason of surgery or, if of childbearing potential, she used one of the following methods of contraception: double barrier, intrauterine device or abstinence. Exclusion Criteria: * Subjects who did not conform to the above inclusion criteria, OR * Subjects who had a clinically relevant history or presence of respiratory, gastrointestinal, renal, hepatic, haematological, lymphatic, neurological, cardiovascular, psychiatric, musculoskeletal, genitourinary, immunological, dermatological, connective tissue diseases or disorders. * Subjects who had a clinically relevant surgical history. * Subjects who had a clinically relevant family history. * Subjects who had a history of relevant atopy. * Subjects who had a history of relevant drug hypersensitivity. * Subjects who had a history of alcoholism or drug abuse. * Subjects who consumed more than 28 units of alcohol a week. * Subjects who had a significant infection or known inflammatory process on screening and/or admission. * Subjects who had acute gastrointestinal symptoms at the time of screening and/or admission (e.g., nausea, vomiting, diarrhoea, heartburn). * Subjects who had an acute infection such as influenza at the time of screening and/or admission. * Subjects who had used prescription drugs within 4 weeks of first dosing. * Subjects who had used oral contraceptives or over the counter medication excluding oral routine vitamins but including mega dose vitamin therapy within one week of first dosing. * Subjects who had used any investigational drug and/or participated in any clinical trial within 3 months of their first admission to the study. * Subjects who had previously received BIA 3-202. * Subjects who had donated and/or received any blood or blood products within the previous 3 months prior to screening. * Subjects who were vegetarians, vegans and/or had medical dietary restrictions. * Subjects who could not communicate reliably with the investigator. * Subjects who were unlikely to co-operate with the requirements of the study. * (If woman) She was pregnant or breast-feeding. * (If woman) She was at childbearing potential and she did not use an approved effective contraceptive method or she used oral contraceptives. * Subjects who were unwilling or unable to give written informed consent.