TABLE 4.
Ritonavir pharmacokinetics in plasma and in liver tissue samples from rats receiving 20-mg/kg dosesa
| Ritonavir pharmacokinetic parameter | Value |
|||||
|---|---|---|---|---|---|---|
| Plasmab | Tissue samplesc |
|||||
| Surgical resection | CNB | FNA5 | FNA3 | FNA1 | ||
| Tmax (h) | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 |
| Cmax (ng/ml) | 1,842 | 20,370 | 14,700 | 10,317 | 14,078 | 9,587 |
| AUC0–24 (ng · h/ml) | 6,913 | 74,686 | 67,483 | 49,166 | 50,539 | 35,461 |
| t1/2 (h) | 7.0 | 12.9 | 4.9 | 3.6 | 5.4 | 4.2 |
One rat (corresponding to the 4-h time point) was excluded from these analyses because ritonavir was not at steady state. Abbreviations: CNB, core needle biopsy; FNA1, fine-needle aspiration with 1 pass; FNA3, fine-needle aspiration with 3 passes; FNA5, fine-needle aspiration with 5 passes; AUC, area under the concentration-time curve; Cmax, maximum observed concentration; t1/2, half-life; Tmax, time of maximum observed concentration.
The plasma concentrations corresponding to 24 and 25 h postdose were below the assay's lower limit of quantitation, and their values were thus set at 0.625 ng/ml.
Concentrations measured in tissue samples were converted from nanograms per gram to nanograms per milliliter by using a liver tissue density value for rats of 1.05 g/ml (32).