Bioequivalence of diclofenac sodium retard

INTERVENTION: Diclofenac Group Diclofenac sodium retard and then Voltaren Retard: Patients will receive a unique dose of 100mg (a tablet) of Diclofenac sodium retard by oral route between 8:00 and 9:00am. After a washout period of 15 days, they will receive a unique dose of 100mg (a tablet) of Voltaren Retard by oral route between 8:00 and 9:00am too. Group Voltaren Retard and then Diclofenac sodium retard: Patients will receive a unique dose of 100mg (a tablet) of Voltaren Retard by oral route between 8:00 and 9:00am. After a washout period of 15 days, they will receive a unique dose of 100mg (a tablet) of Diclofenac sodium retard by oral route between 8:00 and 9:00am too. Voltaren Retard Diclofenac sodium retard CONDITION: Arthritis, Rheumatoid Rheumatoid Arthritis PRIMARY OUTCOME: Pharmacokinetic variable ‐ Plasma levels of diclofenac sodium (values expressed in ng/mL): Measuring time: At the beginning and at 0.5; 0.75; 1; 1.33; 1.66; 2; 2.50; 3; 4; 6; 8; 10; 12 and 24 hours after oral administration. SECONDARY OUTCOME: Clinical safety Vital signs (body temperature in degrees centigrade, heart rate in beats / minute, blood pressure in mm Hg and respiration rate in breaths per minute). Measuring time: Prior to administration of the tablets, during the first 4 hours after administration, and at the end of each period. Biological safety Hematology and clinical biochemistry determinations (numerical values as units of measurement for each determination). Measuring time: At the beginning and end of the study. INCLUSION CRITERIA: o Written informed consent. o Aged between 18‐50 years. o Volunteers of both sexes. o Volunteers' weight: +/‐ 15% of their ideal weight for height. o Failure to submit evidence of organic or psychiatric disease according to interrogation, physical examination and laboratory tests. o Not have evidence or history of diseases such as bronchial asthma, hypertension, bad‐absorption syndrome, peptic ulcer or duodenal present, liver failure, kidney failure, severe allergic reactions, atopic dermatitis, cardiovascular disorders, diabetes mellitus. o Satisfactory physical examination. o Present vital signs values within the following reference ranges. Systolic blood pressure between 90 and 130 mm Hg and diastolic blood pressure between 60 and 80 mm Hg, heart rate between 60 to 100 beats per minute, respiratory rate between 12 to 20 breaths per minute. o Not having consumed alcohol, drinks containing xanthines (tea, coffee, and cola) and carbonated beverages three days before