Concentration decay visualiser
First-order decay applied to a half-life figure taken from published pharmacokinetic work. This illustrates the behaviour of a published parameter. It is not a prediction about any individual, and it assumes idealised single-compartment kinetics that real biology only approximates.
Parameters
Taken from published pharmacokinetic work.
Published figures on file
Mode
Derived from this half-life
Time until 50% remains7 daysOne half-life, by definition
Time until 10% remains23.3 daysApproximately 3.32 half-lives
Time to approximately 97% of steady state35 daysFive half-lives, the conventional approximation
Steady-state accumulation ratio2.00×At a 168-hour interval, repeated events accumulate to roughly 2.00 times the amount of a single event
Why five half-lives matters
After one half-life, half remains. After five, roughly 3% remains, which is why five half-lives is the conventional approximation both for elimination and for the time to reach steady state under repeated administration at a fixed interval.
Where the model breaks down
Real pharmacokinetics involve absorption phases, distribution into tissue compartments, and saturable elimination. Several compounds in this catalogue have no adequate human pharmacokinetic study at all, in which case there is no half-life figure to visualise and we say so rather than supplying one.