Development of a Robust UPLC Method for Simultaneous Determination of a Novel Combination of Sofosbuvir and Daclatasvir in Human Plasma: Clinical Application to Therapeutic Drug Monitoring
Table 3
Stability of SF and DC in plasma samples under several storage conditions.
Nominal Concentration (ng.ml−1)
SF
DC
25
50
400
3200
6400
50
100
1600
6400
12800
(a) After three freeze/thaw cycles
% Bias % CV
-2.9 5.4
5.2 6.5
-5.4 7.2
4.2 5.3
6.1 9.4
8.5 5.8
-3.5 1.5
-5.8 8.5
-3.1 3.2
-9.4 5.4
(b) short-term storage (48 h) at RT
% Bias % CV
4.1 1.1
4.1 6.5
7.3 5.5
-5.7 3.2
-4.8 5.2
5.1 6.6
6.4 7.3
9.2 1.5
8.4 2.4
-5.0 5.1
(c) long-term storage at −80°C for 6 months
% Bias % CV
3.5 2.1
-3.7 4.4
3.4 3.0
5.1 5.9
7.3 8.6
8.4 3.5
9.4 1.3
-2.0 7.0
-5.7 6.9
-6.3 3.5
(d) Standard solutions kept in refrigerator up to 10 days
% Bias % CV
-2.5 1.0
6.5 3.2
3.8 4.3
2.8 6.5
4.1 7.6
7.3 8.6
-5.7 5.7
-3.9 9.3
-2.8 1.0
1.7 1.3
(e) Solutions kept on bench are stable for 5 days
% Bias % CV
3.9 6.4
6.3 8.3
8.2 9.5
9.0 4.6
1.8 2.7
4.7 3.6
3.9 6.5
2.8 1.6
-3.7 4.9
-4.5 1.7
(f) Frozen plasma samples which undergo heating process (60°C for 60 min)
% Bias % CV
-6.7 5.4
-5.7 7.2
3.7 6.5
4.1 2.7
5.9 3.8
8.6 1.7
4.7 5.2
8.1 7.4
-9.4 6.9
-7.2 1.5
(g) Dried extracts (after SPE procedure) kept at −20°C for 6 days
% Bias % CV
9.5 5.3
4.7 6.2
5.8 8.3
-9.3 6.4
-6.3 9.3
-7.8 6.2
9.5 5.3
-5.2 8.1
-6.0 4.3
-3.7 3.8
(h) Reconstituted extracts in the mobile phase kept at 4°C for 4 days in the auto sampler
