A pharmacokinetic model-independent approach for estimating dose required to give desired steady-state trough concentrations of drug in plasma.

A maintenance dose designed to give a desired minimum concentration of drug in plasma at steady-state can be determined in a model-independent manner assuming that concentration-time data needed for the calculation are obtained after absorption and distribution are complete. Using a few concentration-time points obtained after the first dose, numerical values of beta and Z a parameter consisting of different pharmacokinetic parameters for different models, can be obtained. An administration interval (tau) can be chosen based on beta. Using the values of beta, Z, and tau, a maintenance dose is calculated. This approach will allow calculation of a maintenance dose when drug is present in plasma at the time the first monitored dose is given.