TABLE 5.
Stability of stock solutions and mix solution
| Antibiotica | Stabilityb |
|
|---|---|---|
| Stock solution, 100 mg/ml in water | Mix solution, 5 mg/ml in water | |
| AMX | −23.3 | −10.5 |
| PIP | −4.7 | −7.7 |
| OXA | −10.8 | −11.9 |
| CLX | −1.1 | −2.2 |
| FEP | 7.4 | 3.3 |
| CAZ | −6.7 | −8.7 |
| CTX | −3.1 | −3.6 |
| CFZ | 3.2 | −1.4 |
| IS | −5.2 | 3.3 |
a
AMX, amoxicillin; PIP, piperacillin; OXA, oxacillin; CLX, cloxacillin; FEP, cefepime; CAZ, ceftazidime; CTX, cefotaxime; CFZ, cefazolin; IS, internal standard.
b
Stability data represent the difference in the signal between solutions stored at −80°C for 4 months and the signal of freshly prepared solutions. Stock solutions were prepared independently, and mix solutions were prepared simultaneously.