Table 1.

Commonly used antibiotic stock concentrations and solvents

Antibiotic	Type	Solventa	Stock conc. (mg/mL)
Ampicillin	Ampicillin sodium	H2O	10
Azithromycin	Azithromycin dihydrate	Ethanol (∼95%)	10
Ceftriaxone	Ceftriaxone disodium salt	H2O	1
Cephalexin	Cephalexin monohydrate	H2O	10
Ciprofloxacin	Ciprofloxacin	0.1 N HCl	1
Colistin	Colistin sulfate	H2O	10
Daptomycin	Daptomycin	H2O	10
Ertapenemb	Ertapenem sodium	H2O	10
Imipenemb	Imipenem monohydrate	H2O	1
Linezolid	Linezolid	H2O	1
Piperacillinc	Piperacillin monohydrate	Methanol	10
Streptomycin	Streptomycin sulfate	H2O	10
Sulfamethoxazole	Sulfamethoxazole	Acetone	50
Tazobactam	Tazobactam	H2O	1
Tetracycline	Tetracycline hydrochloride	Methanol	10
Trimethoprim	Trimethoprim	Methanol	1
Vancomycin	Vancomycin hydrochloride	H2O	10

^aH₂O: deionized water (filtered and autoclaved).

^bStore at -80°C (drug powder and subaliquots); store all other antibiotic subaliquots at 4°C.

^cPiperacillin solubilization requires agitation (3 min).