Daptomycin: 12 Frequently Asked Questions

Posted by John Kim on May 18, 2012 1:31:00 PM

For the last 15 years, A.G. Scientific has been a leading supplier of Daptomycin.  We offer a range of catalog sizes, as well as, multi-kilogram quantities for bulk applications. Additionally, we provide a full service of bottling, sterile formulations, custom packaging, as well as, comprehensive private labeling capabilities.   


Daptomycin, is a product for which we often get questions on the following: solution preparation, storage, stability, handling, trouble shooting, how to avoid common mistakes….  Here are the most Frequently Asked Questions (FAQS) we have received from our customers and the appropriate answers.


ANSWER: is a novel lipopeptide antibiotic used in the treatment of certain infections caused by Gram-positive organisms (Such as Bacillus, Listeria, Staphylococcus, Streptococcus, Enterococcus). It is a naturally occurring compound found in the soil saprotroph Streptomyces roseosporus. Its distinct mechanism of action means that it may be useful in treating infections caused by multi-resistant bacteria.


  • QUESTION: WHAT IS Bio-structure of Daptomycin?

ANSWER: Daptomycin is a cyclic lipopeptide antibiotic produced by the organism Streptomyces roseosporus. Daptomycin consists of thirteen amino acids, ten of which are arranged in a cyclic fashion, and three that adorn an exocyclic tail. Two non-proteinogenic amino acids exist in the lipopeptide, the unusual amino acid L-kynurenine (Kyn), only known to Daptomycin, and L-3-methylglutamic acid (mGlu). The N-terminus of the exocyclic tryptophan residue is coupled to decanoic acid, a medium chain (C10) fatty acid.

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Figure 1. Daptomycin Structure.


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Figure 2.

Daptomycin mechanism of action. Hypothetical steps: step 1, daptomycin binds to the cytoplasmic membrane in a calcium-dependent manner; step 2, daptomycin oligomerizes, disrupting the membrane; step 3, the release of intracellular ions and rapid cell death1.


daptomycin structure, gram positive bacteria treatment, cubicin antibiotic, daptomycin mrsa, daptomycin antibiotic, lipopeptide antibiotic 

Figure 3. Incorporation of fluorescently labeled daptomycin.

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  • QUESTION: WHAT IS Mechanism of action?

ANSWER: Daptomycin has a distinct mechanism of action, disrupting multiple aspects of bacterial cell membrane function. It appears to bind to the membrane and cause rapid depolarization, resulting in a loss of membrane potential leading to inhibition of protein, DNA and RNA synthesis, which results in bacterial cell death.


  • QUESTION: Is Daptomycin used for MRSA (Methicillin-Resistant Staphylococcus Aureus)?

ANSWER: Daptomycin is used to treat MRSA, which is resistant to methicillin and other related antibiotics. Daptomycin is considered a novel antibiotic and is used to treat Gram-positive bacteria like MRSA.


ANSWER: Briefly, biosynthesis is initiated by the coupling of decanoic acid to the N-terminal tryptophan, followed by the coupling of the remaining amino acids by nonribosomal peptide synthetase (NRPS) mechanisms. Finally, a cyclization event occurs, which is catalyzed by a thioesterase enzyme, and subsequent release of the lipopeptide is granted.

The biosynthetic genes for daptomycin, a calcium-dependent antibiotic, have been cloned, sequenced, analyzed bioinformatically, genetically, and biochemically. The resultant information on the organization and expression of The non-ribosomal peptide synthetase(NRPS) genes, among others, has been exploited and utilized to create combinatorial libraries of hybrid lipopeptide antibiotics related to daptomycin that have proven as effective antibiotics thus far in clinical trials .


  • QUESTION: Are there alternative names? 

ANSWER: Yes, It is marketed in the United States under the trade name Cubicin (Cubist Pharmaceuticals).


ANSWER: Daptomycin should be further diluted with 0.9% sodium chloride injection to be administered by IV infusion over a period of 30 minutes.

Since no preservative or bacteriostatic agent is present in this product, aseptic technique must be used in preparation of final IV solution. Stability studies have shown that the reconstituted solution is stable in the vial for 12 hours at room temperature or up to 48 hours if stored under refrigeration at 2 to 8ºC (36 to 46ºF). The diluted solution is stable in the infusion bag for 12 hours at room temperature or 48 hours if stored under refrigeration. The combined time (vial and infusion bag) at room temperature should not exceed 12 hours; the combined time (vial and infusion bag) under refrigeration should not exceed 48 hour


  • QUESTION: Does material need to be packaged under inert gas?

ANSWER: Yes, It is packaged under inert gas.


  • QUESTION: What are the basic chemical data:

ANSWER: Chemical Formula: C72H101N17O26, CAS Number:55658-47-4, Appearance: White to off-White crystalline powder, Identification: Conforms with reference by HPLC, Molecular Mass: 1619.7086 g/mol, Storage: Store at +4 ºC. Protect from moisture.


  • QUESTION: What are Physical and Chemical Properties:

ANSWER: Melting Point: 215 ºC, Water solubility: Highly soluble(> 1000 mg/ml), PH: 4.0-4.5


ANSWER: Soluble in ethanol, methanol, DMF or DMSO. Limited water solubility.


  • QUESTION: Is there any Toxicological Information?

ANSWER: Yes. Oral: No apparent adverse effects at dose levels up to 2000 mg/kg, Skin: Rabbit, 200 mg/kg, no deaths or toxicity, Intravenous: Rat, median lethal dose 151 mg/kg, coma, convulsions, tremors, incoordination, hindlimb paralysis, reduced activity. Dog, 200 mg/kg, no deaths, reduced body weight, reduced appetite, liver enzyme changes. Monkey, median lethal dose estimated between 25 mg/kg and 200 mg/kg, mortality, lethargy, ataxia, severe muscle weakness, pale facial skin, liver enzyme changes.

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Topics: antibiotics, mrsa bacteria, clinical trials, genetically, stability, bacteria, calcium, bioinformatically, biochemically, daptomycin structure, gram positive bacteria treatment, cubicin antibiotic, daptomycin mrsa, daptomycin antibiotic, lipopeptide antibiotic, gram-positive, solution, solution preparation, formulation, sterile, mrsa