Bacterial cell wall synthesis

Fosfomycin sodium 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]. With a 90% inhibition rate, fosfomycin sodium exhibits bactericidal efficacy against a range of Gram-positive and Gram-negative pathogenic bacteria, including β-bacteria that produce carbapenemase and extended-spectrum lactamases[1]. Because of its wide tissue penetration, fosfomycin sodium is useful in the research of infections pertaining to the lungs, soft tissue, bone, central nervous system, and abscesses [2].

In rats, fosfomycin (80 mg/kg; orally or intravenously) protects against double bekacin nephrotoxicity and is unaffected by administration routes [3]. Rats' fosfomycin pharmacokinetics [4] Dibekacin dosage (mg) Vdss (l/kg) β (min-1) T1/2 (min) Urinary recovery rate (%) 30 0.261 0.0244 28.4 85

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 [1].

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 [1].

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 Dibekacin, at the same time, 0.5 hrs (hrs (hours)) later, later 1 hour; 11 days
Experimental Results: Following previous treatment, polyuria, proteinuria, enzymes and cytosine were diminished due to dibekacin (40 mg/kg).

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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.

Absorption, Distribution and Excretion
Fosfomycin is a low molecular weight and hydrophilic drug. When administered orally, fosfomycin is rapidly absorbed in the small intestine and distributed widely to the tissues. The oral bioavailability ranges from 34-58%. Co-administration of fosfomycin with food decreases gastrointestinal absorption to approximately 30%. The reported AUC = 145-228 mg x h/L, while the reported Cmax = 26.1 (∓9.1) mcg/mL.
Fosfomycin is excreted almost entirely by the kidneys. Factors including administration with food, impaired renal function, and older age may reduce the rate of fosfomycin elimination.
In healthy subjects, the volume of distribution (Vd) of fosfomycin is approximately 0.3 L/Kg. Due to changes in the vascular endothelium, the Vd can be up to 50% higher in critically ill patients.
In one study, the reported CL/F of fosfomycin in healthy volunteers was 17 ∓ 4.7 L/hour.

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Metabolism / Metabolites
Fosfomycin is not metabolized and is predominantly excreted unchanged in the urine.

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Biological Half-Life
The mean elimination half-life of fosfomycin is 5.7 (∓2.8) hours.

Hepatotoxicity
Serum aminotransferase elevations occur in a small proportion of patients after a single oral dose of fosfomycin (1-2%), but at rates similar to those with comparator antibiotics. Nevertheless, serum enzyme elevations are mentioned as potential adverse events in the product label for fosfomycin. In addition, a small number of cases of clinically apparent liver injury attributed to fosfomycin have been published. The time to onset has been short, within one week of a single oral dose or within the first week of intravenous therapy, and the pattern of liver enzyme elevations has been mixed or hepatocellular. The injury has typically been mild and self-limited, and no cases of fatal acute liver failure, chronic hepatitis or vanishing bile duct syndrome have been convincingly linked to fosfomycin. The number of cases described has been too few to establish a typical clinical pattern, but immunoallergic features and autoimmune markers appear to be uncommon.
Likelihood score: D (possible rare cause of clinically apparent liver injury).

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Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
Limited information indicates that fosfomycin produces low levels in milk and is unlikely to be absorbed well by the infant because of the binding to calcium in the milk. It is unlikely to cause any adverse effects in breastfed infants.
◉ Effects in Breastfed Infants
Relevant published information was not found as of the revision date.
◉ Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.

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Protein Binding
Fosfomycin does not bind to plasma proteins to any significant extent.

[1]. Falagas ME, et al. Fosfomycin. Clin Microbiol Rev. 2016 Apr. 29(2):321-47.
[2]. Dijkmans AC, et al. Fosfomycin: Pharmacological, Clinical and Future Perspectives. Antibiotics (Basel). 2017 Oct 31. 6(4):24.
[3]. 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.

Fosfomycin is a phosphonic acid having an (R,S)-1,2-epoxypropyl group attached to phosphorus. It has a role as an antimicrobial agent and an EC 2.5.1.7 (UDP-N-acetylglucosamine 1-carboxyvinyltransferase) inhibitor. It is an epoxide and a member of phosphonic acids. It is functionally related to a phosphonic acid. It is a conjugate acid of a (1R,2S)-epoxypropylphosphonate(1-).
Fosfomycin was discovered in 1969 by scientists at the Spanish Penicillin and Antibiotics Company and is produced by Streptomyces fradiae. It may also be produced synthetically and is commercially available as the disodium salt for intravenous administration and as the calcium or trometamol salt for oral administration. In terms of chemical structure, fosfomycin is a phosphoenolpyruvate analog and contains a phosphonic group and an epoxide ring. Due to its ease of administration as a single 3-gram oral dose and desirable safety profile, fosfomycin has largely become a first-line therapeutic option for the treatment of uncomplicated urinary tract infections (UTIs) in females. Despite being FDA approved only for urinary tract infections, fosfomycin actually has a broad spectrum of activity and is active against both gram-positive and gram-negative bacteria. As such there is great interest in exploring the usefulness of fosfomycin for indications beyond the treatment of UTIs.
Fosfomycin is an orally available, broad spectrum antibiotic used largely for treatment of uncomplicated urinary tract infections. Fosfomycin is associated with a low rate of transient serum enzyme during therapy and with rare cases of clinically apparent acute liver injury with jaundice.
Fosfomycin has been reported in Arabidopsis thaliana, Streptomyces wedmorensis, and other organisms with data available.
Fosfomycin is a phosphoenolpyruvate analogue 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, thereby eventually causing cell lysis and bacterial cell death.
An antibiotic produced by Streptomyces fradiae.
See also: Fosfomycin Tromethamine (active moiety of); Fosfomycin calcium (is active moiety of); Fosfomycin monosodium (is active moiety of).

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Drug Indication
Fosfomycin is indicated for the treatment of uncomplicated cases of cystitis caused by susceptible strains of _Escherichia coli_ and _Enterococcus faecalis_. Fosfomycin is not officially indicated for the treatment of pyelonephritis or perinephric abscess, although there have been reported cases of off-label usage in these situations.
FDA Label

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Mechanism of Action
Fosfomycin exerts its bactericidal effects by binding covalently to a cysteine in the active site of the UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) enzyme, rendering it inactive. By preventing MurA from catalyzing the condensation of phosphoenolpyruvate (PEP) with UDP-N-acetylglucosamine (UNAG), fosfomycin inhibits the production of the peptidoglycan precursor UDP N-acetylmuramic acid (UDP-MurNAc). Ultimately, the first step of bacterial cell wall synthesis is disrupted. In _Escherichia coli_, fosfomycin gains entry into bacterial cells via two mechanisms: the L-alpha-glycerophosphate system and the hexose-6-phosphate transporter system. Fosfomycin also has important effects on cell adhesion. For example, the adhesion of bacterial cells to urinary epithelial cells is reduced in the presence of fosfomycin. The adhesion of _Streptococcus pneumoniae_ and _Haemophilus influenzae_ to respiratory epithelial cells is also reduced

C3H7O4P

138.05908

138.008

C, 26.10; H, 5.11; O, 46.35; P, 22.44

23155-02-4

Fosfomycin calcium;26016-98-8;Fosfomycin sodium;26016-99-9;(Rac)-Fosfomycin (benzylamine)-13C3;1216461-18-5

446987

Solid powder

1.561g/cm3

342.651ºC at 760 mmHg

94ºC

161.03ºC

0mmHg at 25°C

1.486

-1.4

2

4

1

8

138

2

C[C@H]1[C@H](O1)P(=O)(O)O

YMDXZJFXQJVXBF-STHAYSLISA-N

InChI=1S/C3H7O4P/c1-2-3(7-2)8(4,5)6/h2-3H,1H3,(H2,4,5,6)/t2-,3+/m0/s1

((2R,3S)-3-methyloxiran-2-yl)phosphonic acid

MK-955 MK 955 MK955 Antibiotic 833A Fosfonomycin

2934.99.03.00

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO: > 10 mM

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.

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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).

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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)

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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).

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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

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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.

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 (Please use freshly prepared in vivo formulations for optimal results.)