Fosfomycin Tromethamine (MK0955) is a potent, blood-brain barrier penetrant phosphoenolpyruvate analog produced by Streptomyces and a synthetic broad-spectrum antibiotic with antimicrobial and bactericidal properties. Fosfomycin binds to and inactivates the enzyme enolpyruvate transferase. This leads to an irreversible blockage of the condensation of uridine diphosphate-N-acetylglucosamine with p-enolpyruvate, which is one of the first steps of bacterial cell wall synthesis.

Physicochemical Properties

Molecular Formula	C7H18NO7P
Molecular Weight	259.19
Exact Mass	259.082
Elemental Analysis	C, 32.44; H, 7.00; N, 5.40; O, 43.21; P, 11.95
CAS #	78964-85-9
Related CAS #	Fosfomycin calcium;26016-98-8;Fosfomycin sodium;26016-99-9
PubChem CID	10199068
Appearance	White to off-white solid powder
Boiling Point	357ºC at 760 mmHg
Flash Point	169.7ºC
Hydrogen Bond Donor Count	6
Hydrogen Bond Acceptor Count	8
Rotatable Bond Count	4
Heavy Atom Count	16
Complexity	192
Defined Atom Stereocenter Count	2
SMILES	C(N)(CO)(CO)CO.P([C@H]1O[C@H]1C)(O)(O)=O
InChi Key	QZJIMDIBFFHQDW-LMLSDSMGSA-N
InChi Code	InChI=1S/C4H11NO3.C3H7O4P/c5-4(1-6,2-7)3-81-2-3(7-2)8(4,5)6/h6-8H,1-3,5H22-3H,1H3,(H2,4,5,6)/t2-,3+/m.0/s1
Chemical Name	[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]azaniumhydroxy-[(2R,3S)-3-methyloxiran-2-yl]phosphinate
Synonyms	Fosfomycin Tromethamine; FOSFOMYCIN TROMETHAMINE; Fosfomycin tromethanol; Tromethamine-fosfomycin; Fosfomycin trometamol salt; Fosfomycin tromethamine [USAN]; Tromethamine, Fosfomycin; Phosphomycin; Phosphonomycin;
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture and light.
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	Bacterial cell wall synthesis
ln Vitro	Fosfomycin tromethamine is an antibacterial agent for epoxy. In contrast to other antibacterial drugs, its mechanism of action involves impeding the first stage of cell wall formation [1]. The bactericidal action of fosfomycin tromethamine is 90% effective against strains of Staphylococcus aureus and a range of Gram-positive and Gram-negative infections, including beta-bacteria that produce carbapenemase and extended-spectrum lactamases[1]. Because of its wide tissue penetration, fosfomycin tromethamine is useful in the research of infections pertaining to the lungs, soft tissue, bone, central nervous system, and abscesses [2].
ln Vivo	Rats administered fosfomycin tromethamine (80 mg/kg; iv-iv or iv-po) are protected against double bekacin nephrotoxicity, and the effect of administration methods is invariant [3]. Fosfomycin trometamol pharmacokinetics in rats [4] Dibekacin dosage (mg) Vdss (l/kg) β (min-1) T1/2 (min) Urinary recovery rate (%) 30 0.261 0.0244 28.4 85
Enzyme Assay	Fosfomycin is a bactericidal antibiotic agent. It inhibits an enzyme-catalyzed reaction in the first step of the synthesis of the bacterial cell wall. Fosfomycin interferes with the first cytoplasmic step of bacterial cell wall biosynthesis, the formation of the peptidoglycan precursor UDP N-acetylmuramic acid (UDP-MurNAc). Specifically, the enzyme UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) is involved in peptidoglycan biosynthesis by catalyzing the transfer of the enolpyruvyl moiety of phosphoenolpyruvate (PEP) to the 3′-hydroxyl group of UDP-N-acetylglucosamine (UNAG). Fosfomycin covalently binds to the thiol group of a cysteine (position 115 in Escherichia coli numbering; target Cys115) in the active site of MurA and consequently inactivates it. This inhibitory action takes place at an earlier step than the action of β-lactams or glycopeptides [2].
Cell Assay	Fosfomycin exerts immunomodulatory effects by altering lymphocyte, monocyte and neutrophil function. It affects the acute inflammatory cytokine response in vitro and in vivo. It suppresses production of tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), and IL-1α and increases production of IL-10, while contradictory data have been published regarding IL-6. On the other hand, concentrations of TNF-α, IL-1β, and IL-6 expressed as protein and mRNA were almost identical with and without fosfomycin in healthy volunteers. Fosfomycin suppresses IL-2 production from T cells, the production of leukotriene B4 (LTB4) from neutrophils, and the expression of IL-8 mRNA by LTB4 from monocytes. Fosfomycin also exhibits an immunomodulatory effect on B-cell activation. Fosfomycin enhances neutrophil phagocytic killing of invading pathogens, even in patients on chronic hemodialysis and renal transplantation). Fosfomycin resulted in enhanced bactericidal ability of neutrophils compared to other antimicrobials. The clinical relevance of the aforementioned actions remains to be elucidated [2].
Animal Protocol	Animal/Disease Models: Fischer 344 rats [3 ] Doses: 320 mg/kg Route of Administration: intramuscularinjection, 5 courses of treatment: 1 hour, 0.5 hrs (hrs (hours)) earlier than debekacin, at the same time, later 0.5 hrs (hrs (hours)), 1 hour late; 11-day Experimental Results: Following previous treatment, polyuria, proteinuria, enzymes, and cytosine due to dibekacin (40 mg/kg) diminished. Animal/Disease Models: Acute renal failure dehydrated Wistar rats (8 weeks old) [4] Doses: 120 mg/kg Route of Administration: intravenous (iv) (iv)injection; 200mg/kg. The first Experimental Results:the elimination rate of rats basically returned to normal, and the nephrotoxicity parameters improved. Protects proximal tubular lysosomes from the effects of aminoglycosides by inhibiting myelopoiesis and protecting the integrity of lysosomal membranes in rats treated with bibekacin.
References	[1]. Dijkmans AC, et al. Fosfomycin: Pharmacological, Clinical and Future Perspectives. Antibiotics (Basel). 2017 Oct 31;6(4). pii: E24. [2]. Falagas ME, et al. Fosfomycin. Clin Microbiol Rev. 2016 Apr. 29(2):321-47. [3]. Inouye S, et al. Protective effect of fosfomycin on the experimental nephrotoxicity induced by dibekacin. J Pharmacobiodyn. 1982 Sep. 5(9):659-69. [4]. Inouye S, et al. Mode of protective action of fosfomycin against dibekacin-induced nephrotoxicity in the dehydrated rats. J Pharmacobiodyn. 1982 Dec. 5(12):941-50.
Additional Infomation	Fosfomycin tromethamine is a phosphonoacetic acid. Fosfomycin Tromethamine is the tromethamine salt form of fosfomycin, a synthetic broad-spectrum antibiotic. Fosfomycin tromethamine binds to and inactivates the enzyme enolpyruvyl transferase. This leads to an irreversible blockage of the condensation of uridine diphosphate-N-acetylglucosamine with p-enolpyruvate, which is one of the first steps of bacterial cell wall synthesis, thereby eventually causing cell lysis. In addition, fosfomycin tromethamine reduces the adherence of bacteria to uroepithelial cells. (NCI05) An antibiotic produced by Streptomyces fradiae. See also: Fosfomycin (has active moiety).

Solubility Data

Solubility (In Vitro)

H2O: ~250 mg/mL (964.5 mM)

Solubility (In Vivo)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples. Injection Formulations (e.g. IP/IV/IM/SC) Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline) *Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution. Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil) Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals). Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)] *Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline) Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline) Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline) Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil) Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Oral Formulations Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium) Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals). Oral Formulation 3: Dissolved in PEG400 Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose Oral Formulation 6: Mixing with food powders Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	3.8582 mL	19.2909 mL	38.5817 mL
	5 mM	0.7716 mL	3.8582 mL	7.7163 mL
	10 mM	0.3858 mL	1.9291 mL	3.8582 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.