[Curve fitting taken maximum observed blood drug concentration as restricted condition for drug administered by non-vascular route].

When using classical method to make curve fittings of blood drug concentration-time data for drugs administered by non-vascular route (for example, po or im), a considerable difference between maximal values of calculated and observed blood drug concentrations is often seen. The calculated value is often much lower than the observed one. In this paper, a least square method with restricted condition is suggested for solving this problem. Practical calculations confirm that this method solves the problem better.