tdm   an R package for therapeutic drug monitoring Simulation : We validated this tools using simulated date obtained from the mean PK parameters within the range of 2*sd. And the accuracy of PK parameters was validated with percent prediction error (PE%) . And there are two ways to produce simulated data. In first validation if drug A monitored Cl and Vd, we simulated them obtained from Cl-2*sd plus Vd-2*sd to Cl+2*sd plus Vd+2*sd ; In another validation we simulated PK parameters obtained with mean Cl plus mean Vd within the range of 2*sd or with mean Vd plus mean Cl within the range of 2*sd. Validation Result :    Validation I   Validation II  * Cl mean + Vd sd represents tdm is validated with mean cl plus mean vd within the range of 2*sd  * Cl sd + Vd mean represents tdm is validated with mean cl within the range of 2*sd plus mean Vd Table 6 Validation II of Clearance and Volume of Distribution (%PE) Table 7 Validation II of PK parameters of Ritonavir (%PE) Table 8 Validation II of PK parameters of Enfuvirtide (%PE) Table 9 Validation II of PK parameters of Indinavir (%PE)  * Vmax: maximum rate of metabolism  * Km: plasma concentration at which metabolism is occurring at half the maximum rate Table 10 Validation II of PK parameters of Phenytoin (%PE)  * Cmax: concentration related with maximum suppression of clotting factors  * cl: clearance  * K: first order rate constant for clotting factor degradation  * m: prothrombin complex activity remaining  * Vd: volume of distribution Table 11 Validation II of PK parameters of Warfarin (%PE)