Study DesignGlossary Term
ICH M9
The fraction of an administered dose of a drug that reaches the systemic circulation unchanged, and the rate at which this occurs.
Bioavailability quantifies the extent and rate at which the active ingredient of a drug formulation reaches the systemic circulation, providing a measure of the drug's effective exposure after administration. For drugs given intravenously, bioavailability is by definition 100%, as the entire dose enters the blood directly. For other routes of administration, bioavailability may be substantially lower due to incomplete absorption, first-pass metabolism in the gut wall or liver, or degradation before reaching the systemic circulation.
Two components define bioavailability: extent and rate. The extent of bioavailability, expressed as a percentage, indicates what proportion of the administered dose ultimately reaches the circulation. The rate of bioavailability describes how quickly the drug enters the circulation, influencing the time to onset of action and peak drug levels. Both components are pharmacologically important, as two formulations with identical extent of absorption may produce very different clinical effects if they differ substantially in absorption rate.
Bioavailability assessments are essential for formulation development and for demonstrating bioequivalence between generic and brand-name products. Absolute bioavailability studies compare a non-intravenous formulation to an intravenous reference to determine the true fraction absorbed. Relative bioavailability studies compare different formulations of the same drug, as required for generic approval or when changing formulations during development. Bioequivalence is established when the confidence interval for the ratio of key pharmacokinetic parameters falls within the regulatory acceptance range, typically 80-125% for Cmax and AUC.
Absolute bioavailability
"The absolute bioavailability study demonstrated that only 35% of the oral dose reached the systemic circulation, with first-pass hepatic metabolism accounting for the majority of the pre-systemic loss."
Generic approval
"The bioequivalence study confirmed that the generic formulation met regulatory criteria, with the 90% confidence intervals for both Cmax and AUC falling within 80-125% of the reference product."
A group of participants in a clinical trial who receive a comparator treatment, placebo, or no treatment to serve as a baseline for evaluating the effects of the investigational intervention.
A clinical trial design in which participants receive multiple treatments in sequence, with each participant serving as their own control by receiving all study treatments during different periods.
A systematic approach to increasing the dose of an investigational product during a clinical trial, typically employed in early-phase studies to identify safe and potentially effective dose levels.
A clinical trial in which both the participants and the investigators are unaware of the treatment assignments, providing maximal protection against bias in the conduct and assessment of the study.
The time required for the concentration or amount of a drug in the body to decrease by one-half, reflecting the combined effects of elimination processes.
ICH M9
The fraction of an administered dose of a drug that reaches the systemic circulation unchanged, and the rate at which this occurs.
Bioavailability quantifies the extent and rate at which the active ingredient of a drug formulation reaches the systemic circulation, providing a measure of the drug's effective exposure after administration. For drugs given intravenously, bioavailability is by definition 100%, as the entire dose enters the blood directly. For other routes of administration, bioavailability may be substantially lower due to incomplete absorption, first-pass metabolism in the gut wall or liver, or degradation before reaching the systemic circulation.
Two components define bioavailability: extent and rate. The extent of bioavailability, expressed as a percentage, indicates what proportion of the administered dose ultimately reaches the circulation. The rate of bioavailability describes how quickly the drug enters the circulation, influencing the time to onset of action and peak drug levels. Both components are pharmacologically important, as two formulations with identical extent of absorption may produce very different clinical effects if they differ substantially in absorption rate.
Bioavailability assessments are essential for formulation development and for demonstrating bioequivalence between generic and brand-name products. Absolute bioavailability studies compare a non-intravenous formulation to an intravenous reference to determine the true fraction absorbed. Relative bioavailability studies compare different formulations of the same drug, as required for generic approval or when changing formulations during development. Bioequivalence is established when the confidence interval for the ratio of key pharmacokinetic parameters falls within the regulatory acceptance range, typically 80-125% for Cmax and AUC.
Absolute bioavailability
"The absolute bioavailability study demonstrated that only 35% of the oral dose reached the systemic circulation, with first-pass hepatic metabolism accounting for the majority of the pre-systemic loss."
Generic approval
"The bioequivalence study confirmed that the generic formulation met regulatory criteria, with the 90% confidence intervals for both Cmax and AUC falling within 80-125% of the reference product."
A group of participants in a clinical trial who receive a comparator treatment, placebo, or no treatment to serve as a baseline for evaluating the effects of the investigational intervention.
A clinical trial design in which participants receive multiple treatments in sequence, with each participant serving as their own control by receiving all study treatments during different periods.
A systematic approach to increasing the dose of an investigational product during a clinical trial, typically employed in early-phase studies to identify safe and potentially effective dose levels.
A clinical trial in which both the participants and the investigators are unaware of the treatment assignments, providing maximal protection against bias in the conduct and assessment of the study.
The time required for the concentration or amount of a drug in the body to decrease by one-half, reflecting the combined effects of elimination processes.