Bioavailability Study of BIA 5-453

Inclusion Criteria:

• aged between 18 and 45 years, inclusive.

• had a body mass index (BMI) between 19 and 30 kg/m2, inclusive.

• were healthy as determined by pre-study medical history, physical examination, vitalsigns, complete neurological examination and 12-lead ECG.

• had negative tests for HBsAg, anti-HCVAb and HIV-1 and HIV-2 Ab at screening

• had clinical laboratory test results clinically acceptable at screening and admissionto the first treatment period.

• had negative screen for alcohol and drugs of abuse at screening and admission to thefirst treatment period.

• were non-smokers or smoked ≤ 10 cigarettes or equivalent per day.

• was able and willing to give written informed consent.

Exclusion Criteria:

• had a clinically relevant history or presence of respiratory, gastrointestinal, renal,hepatic, haematological, lymphatic, neurological, cardiovascular, psychiatric,musculoskeletal, genitourinary, immunological, dermatological, endocrine, connectivetissue diseases or disorders.

• had a clinically relevant surgical history.

• had a clinically relevant family history.

• had a history of relevant atopy or drug hypersensitivity.

• had a history of alcoholism or drug abuse.

• consumed more than 14 units of alcohol a week.

• had a significant infection or known inflammatory process at screening or admission tothe first treatment period.

• had acute gastrointestinal symptoms (e.g., nausea, vomiting, diarrhoea, heartburn) atthe time of screening or admission to the first treatment period.

• used medicines within 2 weeks of admission to first period that affected the safety orother study assessments, in the investigator's opinion.

• used any investigational drug or participated in any clinical trial within 3 monthsprior to screening.

• participated in more than 2 clinical trials within the 12 months prior to screening.

• donated or received any blood or blood products within the 3 months prior toscreening.

• was a vegetarian, vegan or with medical dietary restrictions.

• could not communicate reliably with the investigator.

• was unlikely to co-operate with the requirements of the study.

• was unwilling or unable to give written informed consent.