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Bioavailability: Difference between revisions
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==Factors Affecting Bioavailability== | ==Factors Affecting Bioavailability== | ||
Bioavailability of oral drugs or bioactive food components is influenced by several key stages: liberation, absorption, distribution, metabolism, and elimination. The equation representing bioavailability | Bioavailability (F) of oral drugs or bioactive food components is influenced by several key stages: liberation, absorption, distribution, metabolism, and elimination. The equation representing bioavailability is: | ||
:<math>F = F_C \times F_B \times F_A \times F_M</math> | :<math>F = F_C \times F_B \times F_A \times F_M</math> | ||
Where | Where each factor represents a different aspect of how a substance is processed in the body: | ||
* '''F<sub>C</sub> (Liberation)''': This is the fraction of a micronutrient or drug that becomes available from its food matrix or dosage form in the GIT. It's influenced by factors like the physical and chemical form of the substance, processing methods, and the presence of other components that might bind or interact with the nutrient or drug. | |||
* '''F<sub>B</sub> (Bio-accessibility)''': This refers to the portion of the substance that is released from the food product or dosage form and then dissolves in the GIT liquids, making it available for absorption. This stage is affected by various factors including the pH and enzyme activity in the GIT, as well as the solubility and stability of the nutrient or drug in the intestinal environment. | |||
* '''F<sub>A</sub> (Absorption)''': This is the fraction of the substance that passes through the intestinal wall into the systemic circulation. Factors influencing absorption include the integrity of the gastrointestinal mucosa, the presence of transporters and enzymes, and the physicochemical properties of the substance like molecular size, lipophilicity, and charge. | |||
* '''F<sub>M</sub> (Metabolism)''': This represents the fraction of the substance that remains in a bioactive form after undergoing metabolic transformations. This includes changes due to enzymatic activity within the GIT, as well as liver metabolism and systemic circulation. The metabolic stability of a compound and its susceptibility to enzymatic degradation are key factors here. | |||
Each of these stages is crucial in determining the overall bioavailability of a substance, and they are influenced by the chemical breakdown of bioactive elements during processing, manufacture, storage, and transport, as well as interactions within the GIT. | |||
==Improving Bioavailability== | ==Improving Bioavailability== | ||