Bioavailability: Is the term most

Bioavailability is the term most often used to characterize drug absorption. This term has been defined as the relative amount of a drug administered in a pharmaceutical product that enters the systemic circulation in an unchanged form, and the rate at which this occurs [29]. Implicit in this definition is the concept that a comparison is being made. If the comparison is made between an oral and an intravenous formulation of a drug, which by definition has 100% bioavailability, the absolute ... Bioavailability is the fraction of a drug or nutrient that reaches the systemic circulation. Learn how to measure bioavailability using area under the curve (AUC) and how it varies by route of administration, formulation and individual factors. Hence, the bioavailability of all other formulations and routes of administration can be compared to this reference value as an absolute standard, and from this the equation for absolute bioavailability can be derived: The absolute bioavailability then is the dose-corrected area under the curve (AUC) non-intravenous divided by AUC intravenous. Abstract Bioavailability, the degree and rate at which a substance is absorbed into the bloodstream and becomes available to its target site of action, is a critical factor in the efectiveness of medications and the utilization of nutrients. This article provides an overview of bioavailability, exploring the factors that influence it, including the route of administration, chemical characteristics of the substance, and individual variations in metabolism. The route of administration plays a ...