The plasma profile for drugs that follow two-compartment model after oral administration has an absorption phase, a distribution phase and an elimination phase.

These three phases will be very distinct if the rate of absorption is faster than the rate of distribution and both are faster than the rate of elimination. i.e. k_a > α > β

If the absorption rate is similar or slower than the distribution phase, the distribution phase will be masked. The plasma conc-time profile will consist of a combined absorption and distribution phase and an elimination phase.