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Abstract It is useful to divide pharmacokinetic processes in-vivo broadly into two parts, absorption and disposition. Absorption, which applies to all sites of administration other than direct injection into the blood stream,comprises all processes between drug administration and appearance in circulating blood. Disposition comprises both the distribution of a drug into tissues within the body and its elimination. Recently, drug transporters have emerged as significant modifiers of patient’s pharmacokinetics. Transporters play an important role in the processes of drug absorption, distribution and excretion. Interactions involving membrane transporters in organs of elimination (liver, kidney) and absorption (intestine) alter blood concentration time profiles of drugs. Biopharmaceutical drug disposition classification system (BDDCS) was developed as the most popular extension of Biopharmaceutical Classification System (BCS) given by Wu and Benet (2005). It was suggested that classifying molecules based on the extent of metabolism is less ambiguous as compared to permeability or extent of absorption. |