Table 2.
Intra- and inter-day coefficients of variation and recovery for the six drugs in hair.
| Compound | Nominal a (pg/mg) | Intra-day CV (n=5, %) b | Inter-day CV (n=5, %) b | Recovery (M±SD, %) c |
|---|---|---|---|---|
| Lamivudine | 6 | 3.1 | 6.3 | ‒ |
| 10 | 4.3 | 7.6 | 112.5±4.8 | |
| 2000 | 3.0 | 5.4 | 94.4±2.8 | |
| 4000 | 3.2 | 4.3 | 104.2±3.3 | |
| Zidovudine | 10 | 12.4 | 12.0 | ‒ |
| 20 | 6.0 | 7.4 | 98.0±5.9 | |
| 2000 | 3.5 | 6.2 | 96.7±3.4 | |
| 4000 | 3.9 | 5.2 | 108.8±4.2 | |
| Nevirapine | 6 | 6.3 | 5.7 | ‒ |
| 10 | 3.8 | 8.0 | 107.6±4.1 | |
| 20000 | 4.3 | 4.8 | 93.1±4.0 | |
| 40000 | 9.2 | 7.5 | 95.6±8.8 | |
| Efavirenz | 12 | 6.9 | 8.0 | ‒ |
| 20 | 4.7 | 7.3 | 98.8±4.6 | |
| 20000 | 7.8 | 6.7 | 91.1±7.1 | |
| 40000 | 4.3 | 6.3 | 95.7±4.1 | |
| Ritonavir | 8 | 9.1 | 9.2 | ‒ |
| 20 | 3.1 | 5.1 | 105.4±3.2 | |
| 2000 | 3.6 | 4.1 | 112.0±4.0 | |
| 4000 | 2.6 | 3.0 | 112.1±2.9 | |
| Lopinavir | 8 | 7.5 | 7.5 | ‒ |
| 20 | 3.8 | 4.2 | 95.2±3.6 | |
| 4000 | 2.4 | 3.3 | 113.7±2.7 | |
| 10000 | 2.3 | 4.1 | 110.7±2.5 |
a
Intra- and inter-day coefficients of variation (CVs) were calculated at four levels, limits of quantitation (LOQ), low, medium, and high concentrations.
b
Intra-day and inter-day precisions were estimated by CVs.
c
Recovery was evaluated at three levels, low, medium, and high concentrations.