| |
Stability (%) |
|
| |
*Plasma samples **Stock Solution |
|
| Nominal Level (ng/mL) |
Unprocessed
24 hrs 10 wks
RT -20 °C |
Processed
24 hrs 10wks
RT -20°C |
Freeze –Thaw Cycle
1 2 3 |
24hrs 10wks
RT -20°C |
| VD-2
|
|
15 |
89 |
102 |
104 |
101 |
98 |
96 |
97 |
|
|
|
90 |
108 |
94 |
101 |
101 |
99 |
97 |
97 |
98 |
96 |
|
VD-3 |
|
15 |
107 |
98 |
98 |
104 |
106 |
104 |
101 |
|
|
|
90 |
108 |
96 |
101 |
100 |
100 |
98 |
96 |
98 |
96 |
|
25(OH)VD-2 |
|
15 |
102 |
101 |
103 |
101 |
98 |
95 |
98 |
|
|
|
90 |
110 |
98 |
99 |
97 |
99 |
97 |
97 |
97 |
99 |
| 25(OH)VD-3 |
|
15 |
91 |
103 |
112 |
101 |
98 |
95 |
97 |
|
|
|
90 |
101 |
96 |
101 |
98 |
98 |
97 |
97 |
98 |
103 |
Stability (%) = mean measured concentration (n=5) at the indicated time divided by mean measured concentration (n=5) at baseline x 100. *Spiked plasma samples were
processed and analyzed immediately (baseline, data not shown), after 24 hours at room temperature (24 hrs RT), after freezing at –20 °C for 10 weeks (10 wks –20 °C), or
after 1 to 3 cycles of freezing at –20 °C and thawing at room temperature (freeze-thaw), or processed and then analyzed after storing for 24 hours at room temperature (24
hrs RT) or 48 hours at –20 °C (48 hrs -20 °C).** Stock solution, 100 μg/mL in methanol. |
