Drug | BUD | AZL | |||||
---|---|---|---|---|---|---|---|
Parameter | HPLC method | First derivative | Ratio first derivative | HPLC method | Zero order method | ||
BUD sum epimer B + A | BUD epimer B | BUD epimer A | 265 nm | 270 nm | 290 nm | ||
Range of linearity (μg mL−1) | 0.4–40.0 | 6.0–20.0 | 6.0–20.0 | 0.05–40.0 | 1.0–35.0 | ||
Correlation coefficient (r) | 0.9999 | ||||||
Slope (a) | 13.31 | 13.31 | 13.31 | 17 × 10–4 | 38 × 10–4 | 47.48 | 26 × 10–3 |
Intercept (b) | − 0.36 | − 0.07 | − 0.29 | 18 × 10–4 | − 19 × 10–4 | 0.89 | 34 × 10–3 |
% RSDa | 0.72 | 0.75 | 0.68 | 0.81 | 0.85 | 0.84 | 0.76 |
% Errorb | 0.25 | 0.27 | 0.24 | 0.29 | 0.3 | 0.30 | 0.24 |
S.D. of residuals (Sy/x) | 0.844 | 0.429 | 0.415 | 19 × 10–5 | 45 × 10–5 | 0.23 | 26 × 10–4 |
S.D. of intercept (Sa) | 0.457 | 0.233 | 0.225 | 22 × 10–5 | 4 × 10–5 | 0.111 | 136 × 10–5 |
S.D. of slope (Sb) | 0.023 | 0.023 | 0.022 | 2 × 10–5 | 5 × 10–4 | 0.006 | 7 × 10–5 |
LOD (μg mL−1)c | 0.113 | 0.058 | 0.056 | 0.43 | 0.43 | 0.008 | 0.17 |
LOQ (μg mL−1)d | 0.343 | 0.175 | 0.170 | 1.29 | 1.32 | 0.023 | 0.52 |