After randomization, 228 patients belonged to modeling group and 40 patients to the validation group. However, in further steps, the numbers of data were reduced into 212 patients and 34 patients in modeling and selleck chemicals Abiraterone validation group, respectively. In modeling group, the number of patients was reduced in final model, since the covariate model building processes relied on the availability of particular covariate within the patients. Meanwhile, the reduced number of patients in the validation group occurred, because some patients were rejected, since they could not produce the parameters when POSTHOC option was applied. Then, this final figure (Table 1) was used in further analysis. Table 1Summary of demographic and clinical characteristics of the patients in the modeling group and the validation group.
The total number of serum concentrations in modeling group was 391 samples accounted as 1.84 concentrations per patient on average (ranging from 1 Linifanib (ABT-869) to 8 samples/patient). The dosage regimen was varied between patients and within patient. The serum concentrations in regard to blood sampling times (peak, trough, and other) also varied as described in Figure 1. Figure 1Number of vancomycin serum concentrations regarding to blood sampling time in modeling group.In the basic model building step (using 432 concentrations from 228 patients), compartment model was compared between one and two compartment. The results preferred two-compartment model as better model to describe the present population (the decrease in OFV from one-compartment to two-compartment model was 154.
346; ��2, df = 2, P < 0.01). The error models to describe inter- and intraindividual variability were influenced by the nature of data . In the present study, proportional error selleck compound model was best described for interindividual variability, since there was a large degree of variability in the true parameters. On the other hand, an additive error model was chosen for intraindividual variability, since the concentrations were within the narrow range of distribution (89.51% of concentrations were on range of 2�C30mg/L).In the covariate preliminary screening step, covariates were divided into three groups on the basis of the similarity of number of patients who had these covariates. This approach was implemented, since major diagnostic criteria, OFV produced by NONMEM, were influenced by the amount of data.