Bioavailability
Absorption: The process by which a substance enters the bloodstream after administration[1][2].
Active Ingredient: The component of a drug or supplement that produces the intended therapeutic effect[1].
Area Under the Curve (AUC): A measurement used to determine the extent of drug absorption over time[2].
Bioaccessibility: The fraction of a compound that is released from its matrix in the gastrointestinal tract and becomes available for absorption[3].
Bioequivalence: The absence of a significant difference in the rate and extent at which the active ingredient becomes available at the site of drug action when administered at the same molar dose under similar conditions[1][2].
Extraction Ratio: A measure of the effect of first-pass metabolism on bioavailability, calculated as the clearance by the liver divided by hepatic blood flow[4].
First-Pass Metabolism: The process by which a drug is metabolized before reaching systemic circulation, often occurring in the liver or intestinal wall[4].
Food Matrix: The composition and structure of food that can affect the release, mass transfer, accessibility, and stability of various food components[3].
Relative Bioavailability: The amount of a substance that reaches the bloodstream through routes of administration other than intravenous, such as oral or sublingual[2].
Site of Action: The location in the body where a drug or active ingredient exerts its intended effect[1].
Types of Bioavailability
Absolute Bioavailability: The percentage of a substance that reaches systemic circulation when administered through non-intravenous routes, compared to intravenous administration (which is considered 100% bioavailable)[2].
Relative Bioavailability: The comparison of bioavailability between different formulations or routes of administration of the same drug[2].
Factors Affecting Bioavailability
Chemical Instability: Some drugs may be destroyed by stomach acid or enzymes in the gastrointestinal tract, reducing their bioavailability[4].
Excipients: Inactive ingredients added to drug formulations that may affect the bioavailability of the active ingredient[4].
Food Interactions: Certain foods can enhance or inhibit the absorption of drugs or nutrients[3].
Molecular Structure: The chemical composition and arrangement of a substance can influence its ability to be absorbed by the body[3].
Particle Size: Smaller particles generally have higher bioavailability due to increased surface area for absorption[4].
Physiological Factors: Individual variations in metabolism, gut flora, and gastrointestinal conditions can affect bioavailability[3].
Importance of Bioavailability
Dosage Determination: Bioavailability helps in determining the appropriate dosage of drugs or supplements to achieve the desired therapeutic effect[2].
Efficacy: Higher bioavailability generally leads to improved efficacy of drugs or nutrients[3].
Safety: Understanding bioavailability helps in preventing potential toxicity from overdosing or ineffectiveness from underdosing[2].
Supplement Quality: Bioavailability is a key factor in assessing the quality and effectiveness of dietary supplements[5].
Citations:
[1] https://www.fda.gov/media/110310/download
[2] https://study.com/learn/lesson/bioavailability-formula-steps-examples.html
[3] https://pmc.ncbi.nlm.nih.gov/articles/PMC3575927/
[4] https://howmed.net/pharmacology/bioavailability-of-drugs/
[5] https://futureyouhealth.com/about-bioavailability
[6] https://pmc.ncbi.nlm.nih.gov/articles/PMC5019242/
[7] https://pmc.ncbi.nlm.nih.gov/articles/PMC3815990/
[8] https://en.wikipedia.org/wiki/Bioavailability
[9] https://pmc.ncbi.nlm.nih.gov/articles/PMC10745386/
[10] https://www.hollandandbarrett.com/the-health-hub/vitamins-and-supplements/guide-to-bioavailability/
