## Repetitive Extravascular Dosing

## C

_{min}and C_{max }can also be calculated if the drug is administered via an extravascular route. The equations however become more complex. From an equation describing the plasma concentration versus time curve after one extravascular administration(@), our new equation may be written as follows:

## where D is the dose administered and

Fis the fraction of the dosage absorbed. [FD= D_{G}^{O}]## At certain fixed intervals(

T),ndoses of the drug are administered and so the plasma concentrations following thenth dose are obtained by

## where t' is the time elapsed after the

nth dose. Whennis large (as when the plasma [ ] reach a plateau), the terms exp(-nk_{el}T) and exp(-nk_{a}T) become neglibly small and so the equation simplifies to

B.9c-1