Table 3.
Stability of Ceftazidime during Storage in Accufuser Elastomeric Infusion Device, Expressed as Percentage of Original Concentration Remaining (Mean ± SD)*
| Study Day |
Nominal 5 mg/mL |
Nominal 40 mg/mL |
Nominal 60 mg/mL |
|||||
|---|---|---|---|---|---|---|---|---|
|
D5W |
NS |
D5W |
NS |
|||||
| 23°C | 4°C | 23°C | 4°C | 23°C | 4°C | 23°C | 4°C | |
| Observed initial concentration (mg/L) | 5.60 ± 0.22 | 5.50 ± 0.38 | 5.88 ± 0.20 | 5.82 ± 0.16 | 40.45 ± 1.26 | 39.86 ± 0.56 | 60.00 ± 2.87 | 58.13 ± 2.45 |
| 1 | 97.0 ± 3.0 | 101.3 ± 1.8 | 101.0 ± 1.0 | 101.3 ± 0.3 | 92.3 ± 2.1 | 99.7 ± 1.2 | 93.2 ± 0.9 | 98.7 ± 1.1 |
| 2 | 92.7 ± 2.3 | 100.6 ± 0.4 | 98.0 ± 1.0 | 101.5 ± 1.0 | 81.9 ± 0.3 | 94.4 ± 1.0 | 85.9 ± 2.0 | 96.9 ± 1.4 |
| 4 | 74.3 ± 1.5 | 96.1 ± 2.5 | 85.9 ± 3.7 | 98.0 ± 1.6 | 64.9 ± 0.8 | 88.1 ± 0.9 | 73.7 ± 1.7 | 92.9 ± 2.4 |
| 7 | 61.7 ± 1.0 | 90.1 ± 1.4 | 79.8 ± 5.3 | 99.1 ± 0.3 | 52.2 ± 1.2 | 84.5 ± 3.2 | 60.6 ± 5.4 | 91.4 ± 2.4 |
| 11 | 87.1 ± 1.5 | 97.4 ± 3.9 | 78.5 ± 1.7 | 89.1 ± 4.9 | ||||
| 14 | 84.0 ± 1.5 | 94.3 ± 2.4 | 77.1 ± 2.1 | 87.9 ± 2.7 | ||||
| Degradation rate† (%/day) | –5.86 | –1.30 | –3.03 | –0.42 | –6.96 | –1.72 | –5.63 | –0.86 |
| T–90% (days)‡ | 1.97 | 8.78 | 3.69 | 26.36 | 1.11 | 4.94 | 1.50 | 10.06 |
| Fastest degradation rate§ | ||||||||
| Lower limit of 95% CI (%/day) | –7.61 | –1.62 | –4.95 | –0.67 | –9.22 | –2.25 | –6.76 | –1.15 |
| T–90% (days) | 1.31 | 6.19 | 2.02 | 15.01 | 1.09 | 4.45 | 1.48 | 8.68 |
| Estimated % remaining with storage¶ | ||||||||
| 6.5 days at 4°C + 12 h at 23°C | 86.70 | 93.91 | 81.95 | 90.07 | ||||
| 2.5 days at 4°C + 8 h at 23°C | 93.16 | 96.57 | 90.94 | 94.67 | ||||
CI = confidence interval, D5W = dextrose 5% in water, NS = normal saline (0.9% sodium chloride), SD = standard deviation.
Each value was based on duplicate determination of 3 samples. The percent remaining was based on the observed concentration on day 0 (100%).
The degradation rate was determined by linear regression of the percent remaining on each study day.
T–90% is the time for the concentration to decline by 10% (i.e., time to reach 90% of initial concentration), as determined from the degradation rate.
Fastest degradation rate and T–90% were based on the lower 95% confidence limit of the regression-determined slope.
Using the fastest observed degradation rates determined by regression (95% CI), calculations were completed for a solution stored in an Accufuser elastomeric infusion device for 6.5 or 2.5 days, followed by storage for an additional period at room temperature (23ºC).