Tolerability and Steady-state Pharmacokinetics of BIA 6-512

Inclusion Criteria: * Male or female subjects aged between 18 and 45 years, inclusive. * Subjects of body mass index (BMI) between 19 and 30 kg/m2, inclusive. * Subjects who were healthy as determined by pre-study medical history, physical examination, vital signs, complete neurological examination and 12-lead ECG. * Subjects who had clinical laboratory test results clinically acceptable at screening and admission. * Subjects who had negative tests for HBsAg, anti-HCVAb and HIV-1 and HIV-2 Ab at screening. * Subjects who had a negative screen for alcohol and drugs of abuse at screening and admission. * Subjects who were non-smokers or who smoke ≤ 10 cigarettes or equivalent per day. * Subjects who were able and willing to give written informed consent. * (If female) 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. * (If female) She had a negative urine pregnancy test at screening and admission. 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, endocrine, 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 drug or food hypersensitivity. * Subjects who had a history of alcoholism or drug abuse. * Subjects who consumed more than 21 units of alcohol a week. * Subjects who had a significant infection or known inflammatory process on screening or admission. * Subjects who had acute gastrointestinal symptoms at the time of screening or admission (e.g., nausea, vomiting, diarrhoea, heartburn). * Subjects who had used medicines within 2 weeks of first admission that, in the opinion of the investigator, may affect the safety or other study assessments. * Subjects who had used any investigational drug or participated in any clinical trial within 2 months of their admission. * Subjects who had donated or received any blood or blood products within the previous 2 months prior to screening. * Subjects who were vegetarians, vegans or have medical dietary restrictions. * Subjects who cannot communicate reliably with the investigator. * Subjects who were unlikely to co-operate with the requirements of the study. * Subjects who were unwilling or unable to give written informed consent. * (If female) She was pregnant or breast-feeding. * (If female) She was of childbearing potential and she did not use an approved effective contraceptive method (double-barrier, intra-uterine device or abstinence) or she used oral contraceptives.