Table 3.

Percentage of Initial Concentration of Hydromorphine (0.2 mg/mL) and Ketamine (0.6 mg/mL) Remaining after 7 Days of Storage at 25°C in Glass Bottles, Plastic Syringes, or IV Bags

Variable	Glass Bottles		Plastic Syringes		IV Bags
	Hydromorphone	Ketamine	Hydromorphone	Ketamine	Hydromorphone	Ketamine
Initial concentration (mg/mL)*	0.186±0.007	0.602±0.008	0.179±0.155	0.543±0.023	0.164±0.012	0.543±0.009
Study day
1	101.08	100.50	96.21	93.37	97.56	99.82
2	94.09	99.17	96.65	101.84	109.15	101.29
3	99.46	103.65	93.85	98.34	102.44	95.58
7	104.84	104.65	90.50	95.95	91.46	106.08
Estimated % remaining on day 7†	97.86	99.67	98.66	98.70	103.52	98.37
Lower 95% CI for % remaining‡	90.05	96.44	95.98	90.91	90.38	91.12

CI = confidence interval.

*Nominal initial concentrations: hydromorphone 0.2 mg/mL, ketamine 0.6 mg/mL.

†Calculated from concentration on day 7 as determined by linear regression and concentration observed on day 0, according to the following formula: concentration on day 7 divided by concentration on day 0 x 100.

‡Calculated from lower limit of 95% CI of the slope of the curve relating concentration to time, determined by linear regression, according to the following formula: lower limit of 95% CI of (concentration on day 7 divided by concentration on day 0) x 100.