Effect of BIA 5 1058 on Cardiac Repolarization

This will be a Phase 1, randomized, double-blind, placebo-controlled and open-label, active controlled, 4 period, crossover study in healthy male and female subjects under fed conditions. The study will be double blinded for BIA 5-1058 and placebo and open label for moxifloxacin. The central ECG laboratory and ECG readers will be blinded to study treatment sequence, timepoint, and subject. All subjects will receive each of the following 4 treatments: * 400 mg BIA 5 1058 * 1200 mg BIA 5 1058 * placebo * 400 mg moxifloxacin Potential subjects will be screened to assess their eligibility to enter the study between 28 and 3 days prior to the first treatment administration. For each treatment period, subjects will be admitted into the Clinical Research Unit (CRU) on Day 2 and be confined to the CRU until Discharge on Day 4. Each subject will receive a single dose of study medication on Day 1 of each treatment period. There will be a washout of at least 10 days between doses, and subjects will return to the CRU for a Follow-up visit 14 ± 2 days after Period 4 Discharge. The total duration of study participation for each subject from Screening through Follow-up visit) is anticipated to be approximately 80 days. The start of the study is defined as the date the first enrolled subject signs an Informed Consent Form (ICF). The point of enrollment occurs at the time of subject number allocation. The end of the study is defined as the date of the last subject's last assessment (scheduled or unscheduled).