3.2. Specificity and selectivity
The specificity analysis allowed testing potential interferences
of 49 drugs including anti-infective agents, immunosuppressive
agents, analgesics and antiepileptic drugs. No significant
interference from endogenous or exogenous compounds was
observed in the chromatograms of plasma from 10 patients
experiencing severe renal or hepatic impairment and 20
patients.
3.3. Linearity, accuracy, precision and LLOQ
The Levene statistic test showed a significant difference
(p < 0.05) between variances of each standard concentration. As
the variance grew proportionally to the concentration, the best
weighting factor was 1/(peak area ratio). Calibration curves were
linear up to 100 mg/L for vemurafenib and 4000 g/L for erlotinib.
Fig.