Comparative Bioavailability Between Two Tramadol Formulations: Study of the Better Controlled Release of a New 200 mg Once A Day (OAD) Formulation Versus Zytram® 200 mg

Inclusion Criteria: * Healthy subjects of either gender * Age between 18 and 45 years * Body mass index between 19 and 27kg/m2 * Normal medical history * Normal or no clinically significant physical examination findings * Normal or no clinically significant findings in analytical tests * Negative hepatitis B, hepatitis C or HIV serology * Negative drugs of abuse in urine * Negative pregnancy test in females * The subject understands and accepts the study procedures and grants in writing his/her informed consent Exclusion Criteria: * Did not fulfill the inclusion criteria * Organic disorders or underwent major surgery, within 90 days before study screening * Psychiatric history * Alcohol drink intake greater than 30gr/day * Cigarette smoking greater than 10 cigarettes/day * Excessive consumption of food or beverages containing xanthines (more than five units of coffee, tea or cola per day) * Medical treatment within 30 days before screening, and/or any medication 7 days before starting the study * Participation in other clinical study or donate blood within 90 days before starting this study * Antecedents of gastric, hepatic, renal and other kind of disorder that could affect ADME (absorption, distribution, metabolism or excretion of the study drug) * Hepatitis B, hepatitis C or HIV positive serology * Pregnant or breastfeeding * Clinically relevant hypersensitivities (in particular to drugs) * Woman taking oral contraceptive drugs * Incapable of communicating and cooperating with investigators