Acetazolamide as the sodium salt is available in 500-mg (unpreserved) vials with sodium hydroxide and, if necessary, hydrochloric acid to adjust the pH.3011; 3030 Each 500-mg vial should be reconstituted with at least 5 mL of sterile water for injection.3011; 3030
pH
Osmolality
The osmolality of acetazolamide sodium 500 mg was calculated for the following dilutions:1054
| Osmolality (mOsm/kg) | ||
|---|---|---|
| Diluent | 50 mL | 100 mL |
| Dextrose 5% | 321 | 291 |
| Sodium chloride 0.9% | 348 | 317 |
Sodium Content
2.049 mEq/500 mg (calculated).846
Administration by direct intravenous injection is preferred; intramuscular injection is not recommended.3011; 3030
Intact vials should be stored at controlled room temperature.3011; 3030 Acetazolamide is a white to faintly yellowish white powder.3011; 3030 The manufacturers state that the reconstituted solution is physically and chemically stable for 3 days at 2 to 8°C or for 12 hours at 20 to 25°C; however, storage of the reconstituted solution at 2 to 8°C and use of the solution within 12 hours after reconstitution is recommended.3011; 3030 Any unused portion should be discarded.3011; 3030
pH Effects
The stability of acetazolamide sodium in aqueous solution appears to decrease as the pH increases above 9. At pH 8.8, a 0.25-mg/mL solution retained 96% of the initial amount after 3 days at 25°C; at pH 10.8 and 12.7, 88 and 83% of the concentration, respectively, remained after 4 days.1230 Acetazolamide exhibits maximum stability at pH 4.1424
Sorption
Acetazolamide sodium was shown not to exhibit sorption to PVC bags and tubing, polyethylene tubing, Silastic tubing, and polypropylene syringes.536; 606
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