Stability of daptomycin reconstituted vials and infusion solutions.

Objectives: Daptomycin is a cyclic lipopeptide with selective action against drug-resistant Gram-positive bacteria. The stability of daptomycin solutions in different containers while stored at different temperatures was assessed.

Methods: Daptomycin vials were reconstituted with NaCl (50 mg/mL). Daptomycin infusion solutions (5.6 and 14.0 mg/mL) were prepared in polypropylene infusion bags. All test solutions were stored either under refrigeration or at room temperature over 7 days. Samples were withdrawn on days 0, 2, 4 and 7 and assayed in triplicate using a stability-indicating high-performance liquid chromatography (HPLC) method.

Results: The HPLC analysis revealed no significant loss in daptomycin concentration in vials or bags when stored at 2-8°C. All samples remained clear and colourless and there were no significant changes in pH throughout the study period.

Conclusions: Reconstituted daptomycin vials (50 mg/mL) and infusion bags (5.6 and 14 mg/mL) were found to be physicochemically stable over a period of 1 week when stored at 2-8°C.