Biomedical Engineering Reference
In-Depth Information
Table 2
Linearity, detection limits, accuracies, and variability for four corticosteroids in plasma
using an ultrasensitive m LC/MS/MS method
Detect limit
in plasma
(pg/mL)
Intra-/interday
variation
c
(%)
Compound
Linearity
a
(
r
2
)
Accuracy
b
(SD)%
BUD
0.985
0.5
107(9), 99(5), 104(4), 102(5)
8.4/6.2
DEX
0.995
1
88(8), 93(10), 89(7), 96(4)
5.9/11.1
TACA
0.997
0.2
94(4), 97(2), 99(3), 102 (2)
3.5/2.3
DEX-AC
0.994
0.6
95(6), 93(5), 95(7), 93(6)
9.0/7.7
(Reproduced with permission from American Chemical Society)
a
Calibration standards were prepared in porcine plasma in the concentration range of 5-200 pg/mL
b
Accuracies were determined in triplicate for concentrations of 10,50,400, and 2,500 pg/mL in
plasma
c
Aliquots of plasma samples stored at −20 °C were analyzed six consecutive times in 1 day (intraday,
n =
6), and twice on three different days (interday,
n =
6)
Table 3
Sensitivity, quantification range, and linearity for the four metabolites
Sensitivity (LOD,
pg/mL)
a
Quanti fi cation
range (ng/mL)
Linearity
(
n
= 6) (
r
2
)
VitD metabolites
25-Hydroxy vitamin D2
0.5
0.100-50.0
³ 0.9924
25-Hydroxy vitamin D3
1.0
0.100-50.0
³ 0.9967
1 a , 25-Dihydroxy vitamin D3
0.5
0.005-2.50
³ 0.9913
24(
R
), 25-Dihydroxy vitamin D3
1.0
0.050-25.0
³ 0.9905
(Reproduced with permission from American Chemical Society)
a
De fi ned as S/N
=
3.
cannulation of the suprachoroidal space. Under these conditions, TACA concentrations
in the posterior segment were sustained at therapeutic levels for more than 90 days
[
8
].42 Plasma samples were collected serially for 90 days after suprachoroidal injec-
tion and analyzed for TACA concentration using the method developed here. The
time course of plasma drug concentrations for the treatment group treated with
1.5 mg of TACA is shown in Fig.
7
[
4
]. The results showed that TACA plasma con-
centrations were sustained at high pg/mL levels for roughly the first 7 days and then
decreased to the range of 1-10 pg/mL at around 30 days; this extremely low plasma
concentration was maintained through the last time point, 90 days after treatment.
3
Paradigm 2: Ultrasensitive Quanti fi cation of Anticancer
Drug in Low-Dose Treatment
3.1
Introduction
We applied the similar strategy for ultrasensitive quantification of a clinically impor-
tant anticancer drug, paclitaxel. Although conventional high-dose therapeutic regi-
ments of paclitaxel has been widely used for solid tumors treatment, severe side
effects and acquired drug resistance are becoming major issue in clinical. Numerous
