Stability |
Spiked conc. (pg/ml) |
Mean (± SD) obtained concentration |
% Change (Stability) |
Comparison samples (pg/ml) |
Stability samples (pg/ml) |
Bench topa |
27956.635 |
27428.770 (± 71.101) |
27557.790 (± 74.193) |
0.47 |
14537.450 |
13708.226 (± 125.746) |
13916.554 (± 53.782) |
1.52 |
290.749 |
279.777 (± 4.203) |
284.292 (± 2.066) |
1.61 |
Process stabilityb |
27956.635 |
27466.251 (± 107.836) |
27348.265 (± 322.401) |
–0.43 |
14537.450 |
14430.853 (± 107.114) |
14353.333 (± 131.016) |
–0.54 |
290.749 |
291.135 (± 3.740) |
289.277 (± 7.848) |
–0.64 |
Freeze/thawc |
27956.635 |
27684.246 (± 72.812) |
27549.256 (± 132.294) |
–0.49 |
14537.450 |
13914.170 (± 126.952) |
13768.270 (± 95.724) |
–1.05 |
290.749 |
272.259 (± 4.331) |
275.954 (± 4.053) |
1.36 |
Freeze/thawd |
27956.635 |
27684.246 (± 72.812) |
27556.702 (± 182.816) |
–0.46 |
14537.450 |
13914.170 (± 126.952) |
13742.464 (± 74.795) |
–1.23 |
290.749 |
272.259 (± 4.331) |
275.627 (± 3.827) |
1.24 |
Long terme |
27956.635 |
29103.028 (± 276.083) |
29116.039 (± 376.954) |
0.04 |
14537.450 |
15159.266 (± 105.244) |
15144.490 (± 147.049) |
–0.10 |
290.749 |
293.156 (± 12.237) |
292.720 (± 12.506) |
–0.15 |
Long termf |
27956.635 |
29103.028 (± 276.083) |
29266.360 (± 685.306) |
0.56 |
14537.450 |
15159.266 (± 105.244) |
15145.190 (± 94.743) |
–0.09 |
290.749 |
293.156 (± 12.237) |
293.062 (± 10.547) |
–0.03 |
Long termg |
27956.635 |
29082.193 (± 323.626) |
28937.989 (± 291.306) |
–0.50 |
14537.450 |
15091.547 (± 76.126) |
15036.159 (± 135.769) |
–0.37 |
290.749 |
307.782 (± 13.278) |
306.090 (± 13.228) |
–0.55 |
Long termh |
27956.635 |
29082.193 (± 323.626) |
29009.723 (± 549.216) |
–0.25 |
14537.450 |
15091.547 (± 76.126) |
15075.167 (± 94.549) |
–0.11 |
290.749 |
307.782 (± 13.278) |
310.764 (± 13.021) |
0.97 |
|
* - % Change – Determined by calculating the percentage change of mean of stability QC concentration against mean of comparison QC concentrations |
aAfter 6 hours at room temperature |
bAfter 75 hours in autosampler at 10°C |
cAfter five freeze/thaw cycles at –30°C |
dAfter five freeze/thaw cycles at –75°C |
eLong term matrix stability at –30°C for 72 days |
fLong term matrix stability at –75°C for 72 days |
gLong term matrix stability in presence of ethinyl estradiol at –30°C for 73 days |
hLong term matrix stability in presence of ethinyl estradiol at –75°C for 73 days |
Table 3: Stability results for levonorgestrel (n=6). |