The impact of lower
serum albumin levels on
teicoplanin pharmacokinetics has not been previously determined. The authors assessed the relationship between total and free concentrations of
teicoplanin in serum samples obtained from patients receiving
teicoplanin therapy for
Gram-positive bacterial infections. In addition, the authors determined the contribution of
serum albumin concentrations to the unbound fraction of
teicoplanin. One hundred ninety-eight serum samples were obtained from 65 patients undergoing routine therapeutic
drug monitoring of
teicoplanin. Free serum
teicoplanin was separated by ultrafiltration, and total and free serum concentrations of
teicoplanin were determined by a fluorescence polarization immunoassay. Regression analysis was then performed to build a prediction model for the free serum
teicoplanin concentration from the total serum
teicoplanin concentration and the
serum albumin level using the first 132 samples. The predictive performance of this model was then tested using the next 66 samples. Free serum
teicoplanin concentrations (Cf) (mug/mL) were predicted using a simple model constructed using total serum
teicoplanin (Ct) (mug/mL) and
albumin concentrations (ALB) (g/dL): Cf = Ct/(1 + 1.78 * ALB). This model could estimate free serum
teicoplanin concentrations with a small bias and an acceptable error. The measured free level of
teicoplanin will lie between 0.63 and 1.38 times the predicted concentration in 95% of cases.
Serum albumin level plays a major role in the variability of the fraction unbound of
teicoplanin. This model can reliably estimate free serum
teicoplanin concentrations more easily than by using direct measurements.