Biol. Pharm. Bull. 27(5) 706—709 (2004)

therapeutic applications due to its several pharmacological activities. In humans, ASA is rapidly hydrolyzed to salicylic acid (SA) by nonspecific enzymes found in many tissues. ASA is eliminated from the body by renal excretion and by hepatic biotransformation to salicyluric acid (SUA) and gentisic acid (GA). ASA dosage is determined by the accumulation of the metabolite SA, which has a longer half-life than ASA and consequently is accumulated in the blood. The rate of formation of SUA is inducible, but its continued induction contributes to the clearance of SA. Some authors have studied the possible pharmacokinetic differences of drugs commonly used in ethnic groups from different places in the world. Mexico has great variety of ethnic groups, approximately 63 different cultures are located in the center, southwest and north of the country, site where flourished great cultures. The Otomies, which inhabit in the Valle del Mezquital and in the State of Mexico in the center of the Mexican Republic, are one of the most important ethnic groups of Mexico. The Mesticians comprises the biggest Spanish-speaking population of Mexico and was formed by a mixture of Europeans and Africans with natives. From the point of view of their genetic characteristics, they could present racial differences as pharmacokinetic profiles as their capabilities for drugs biotransformation. Due to the great importance of indigenous population in our country and their possible pharmacokinetic differences with Mestician population, a study to identify such variations has been started. This study was conducted to acquire a better understanding of the changes determined by racial influence on the pharmacokinetics of ASA and its metabolites. The objectives of this study were to determine pharmacokinetic differences of ASA and its metabolites in Otomies group with those of Mestician population, and to characterize metabolic pathways of ASA biotransformation in Otomies group. METHODS