Factors Effecting Bioavailability Studies

Journal: The Pharma Innovation 
Volume: 1
Issue:3

Author: Bodavula Samba Siva Rao

Abstract: The goal of most oral dosage forms is to serve as a vehicle for the delivery of drugs to the blood stream for distribution to the site of action. The therapeutic effectiveness of a drug depends up on the ability of the dosage form to deliver the medicament to the site of action at a rate and amount sufficient to elicit the desired pharmacological action. This attribute of the dosage form is referred as physical availability or simply bioavailability. Bioavailability defined as the rate and extent of absorption of unchanged drug from its dosage form. Bioavailability mainly depends on the absorption efficiency of any dosage form. By definition, when a medication is administered intravenously, its bioavailability is 100%.However, when a medication is administered via other routes (such as orally), its bioavailability decreases (due to incomplete absorption and first-pass metabolism) or may vary from patient to patient (due to inter-individual variation). Bioavailability is one of the essential tools in Pharmacokinetics, as bioavailability must be considered when calculating dosages for non-intravenous routes of administration. Bioavailability of a drug is largely determined by the properties of the dosage form (which depend partly on its design and manufacture), rather than by the drug's physicochemical properties, which determine absorption potential. Bioequivalence means that two or more chemically or pharmaceutically equivalent products produce comparable bioavailability characteristics in any individual when administered in equivalent dosage regimen.

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