To estimate the pharmacokinetics of single doses of benzodiazepines in Mexican adult healthy volunteers: a) alprazolam tablet extended release, b) alprazolam tablet immediate release, and clonazepam tablet.

To determine pharmacokinetics of alprazolam and clonazepam in Latin-American population; in Mexico, both drugs are still widely used as first or second choice in the treatment of anxiety disorders.

Inclusion Criteria:

• Healthy male or female volunteers aged between 18 and 40 years old.

Exclusion Criteria:

• Subjects presenting changes on their vital signs constants registered at volunteers' screening.
• Volunteers with any of the following: noncompliance of proposed inclusion criteria; requiring another drug product throughout the study conduction; pregnant or nursing females; history of cardiovascular, renal, hepatic, muscular, metabolic, gastrointestinal, neurological, endocrine, psychiatric, hematopoietic or any other anemia kind, disease, asthma, or organic disorder; history of dyspepsia, gastritis, esophagitis, duodenal or gastric ulcer or any condition possibly affecting drug absorption; history of acute narrow or glaucoma; exposed to drug products known as hepatic enzyme or inductors; who had received any drug product within 14 days or 5 half lives; who had been hospitalized due to any problem within 60 days prior to study start; history of sensitivity to BZD; who had drink alcohol or any beverage containing xanthines or who had taken smoked food or grapefruit juice within 72 hours prior to start hospitalization period, who had blood donated or lost 450 mL or more within 60 days prior to study start; requiring any special diet regardless the cause.