Lorazepam Stability in Parenteral Solutions for Continuous Intravenous Administration

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Abstract
OBJECTIVE: To determine the stability of lorazepam over a 24-hour period when prepared in polyvinyl chloride (PVC) bags at initial concentrations of 0.08 and 0.5 mg/mL. DESIGN: Each concentration was studied at room (21°C) and refrigerator (4°C) temperatures in dextrose 5% (D5W) and NaCl 0.9% solutions. Duplicate test solution admixtures were prepared for each lorazepam concentration, diluent, and temperature. At 0, 1, 4, 8, and 24 hours, duplicate samples were obtained for visual inspection, pH determination, and concentration determination by stability-indicating, reverse-phase HPLC analysis. Compared with baseline, peaks for lorazepam degradation products were not found on any of the study chromatograms. RESULTS: In D5W and NaCl 0.9% solutions, lorazepam loss in excess of 10% by HPLC analysis occurred for concentrations of 0.08 and 0.5 mg/mL at 1 and 4 hours, respectively. CONCLUSIONS: These data suggest that significant loss of lorazepam occurs as the probable result of sorption to PVC bags when admixed in both D5W and NaCl 0.9% solutions at 21 and 4°C.