Staphylococcus aureus is inhibited by cefapirin at doses ranging from 0.09 to 12.5 mug/mL [2]. Cephapirin, also known as cefapirin, inhibits isolates of Staphylococcus epidermidis, viridans Streptococcus, Streptococcus pyogenes, and Diplococcus pneumoniae by less than 1 μg/ml [2].

Cefapirin (200 mg; intramuscular; dairy cows) is useful for treating Staphylococcus aureus infections in dairy cows [3].

Absorption, Distribution and Excretion
Cephalosporins have poor permeability in cerebrospinal fluid. Approximately 50% of cefepime is bound to plasma proteins. Half-life…approximately 40 minutes in normal individuals, depending on renal function. Large amounts of cefepime in the blood can be removed by hemodialysis. …Primarily excreted via the kidneys; only 1% is present in bile. …Cefepime is not absorbed by the gastrointestinal tract. After intramuscular injection of 0.5 g cefepime, the highest plasma concentration is approximately 10 μg/mL at 45 minutes; at 1 g, it is approximately 16 μg/mL. After a single intramuscular injection of 1 g cefepime, plasma concentrations are still detectable 6 hours later, and it is effective against a variety of susceptible microorganisms. Approximately 30% of the intramuscular dose of cefepime is excreted in the urine within the first 2 hours after injection. For more complete data on the absorption, distribution, and excretion of cefepime (8 metabolites), please visit the HSDB record page.

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Metabolism/Metabolites
The major metabolite detected is deacetylated cefepime.
The major metabolite of cefepime is deacetylated cefepime, which has approximately half the antibacterial activity of the parent cefepime; 20% of the antibiotic activity in plasma is attributed to deacetylated cefepime.
Cefepime is partially metabolized in plasma, liver, and kidneys to diacetylcefepime, which has approximately 50% of the antibacterial activity of the parent compound. …Up to 20% of the antibiotic activity in serum is attributed to the deacetylated metabolite.

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Biological Half-Life
Eight healthy adults received 1 gram of cefepime via intravenous and intramuscular injection, respectively. The biological half-life of cefepime is 43 minutes. The absorption half-life of intramuscularly administered cefepime is 1.25 hours.
Intravenous cefepime sodium exhibits a biexponential distribution pattern in serum and subchondral bone, reaching equilibrium within 20 minutes. The drug is rapidly eliminated, with a β-half-life of approximately 0.3 hours and a clearance rate of 400 mL/min.
The serum half-life is 0.6 hours (data from table).

Interactions
Probenecid and sulfinpyrazone compete with uric acid for renal tubular transport sites. These uricosuric agents can also affect the urinary excretion of other weak acids. ...Cephalosporins...may be affected by the co-administration of probenecid or sulfinpyrazone. /Cephalosporins/ β-lactam antibiotics (penicillins and cephalosporins) may cause significant mutual inactivation when used in combination with aminoglycosides. If used concurrently, they should be administered at different sites. Never mix them in the same infusion bag or bottle. /Cephalosporins/

[1]. Bran JL, et al. Clinical and in vitro evaluation of cephapirin, a new cephalosporin antibiotic. Antimicrob Agents Chemother. 1972 Jan;1(1):35-40.
[2]. Axelrod J, et, al. Cephapirin: in vitro antibacterial spectrum. Appl Microbiol. 1971 Nov;22(5):904-8.
[3]. Roy JP, et, al. Efficacy of a 5-day extended therapy program during lactation with cephapirin sodium in dairy cows chronically infected with Staphylococcus aureus. Can Vet J. 2009 Dec;50(12):1257-62.

Cefepirine is a cephalosporin with an acetoxymethyl group and a 2-(pyridin-4-ylthio)acetamido group substituent at positions 3 and 7 of its cephalosporin skeleton, respectively. It is used as an antibiotic (in sodium salt form) and is effective against both Gram-negative and Gram-positive bacteria. It is an antibacterial drug. It is the conjugate acid of cefepirine (1-). Cefepirine (INN, also spelled cephapirin), usually marketed under the brand name Cefadyl, is a first-generation cephalosporin antibiotic available in injectable form. In the United States, production of cefepirine for human use has ceased. Cefepirine partially binds to plasma and is effective against both Gram-negative and Gram-positive bacteria. Cefepirine has been reported to exist in the Chinese honeybee (Apis cerana), and relevant data are available. Cefepirine is a semi-synthetic, broad-spectrum, first-generation cephalosporin with antibacterial activity. Cefepime binds to and inactivates penicillin-binding proteins (PBPs) located on the inner membrane of bacterial cell walls. PBPs are enzymes involved in the final stages of bacterial cell wall assembly and cell wall remodeling during growth and division. Inactivation of PBPs interferes with the cross-linking of peptidoglycan chains, which is crucial for maintaining the strength and rigidity of the bacterial cell wall. This leads to weakened bacterial cell walls and cell lysis. Cephalosporin antibiotics, partially bound to plasma, are effective against both Gram-negative and Gram-positive bacteria. See also: Cefepime sodium (in salt form); Cefepime benzylcin (active ingredient). Indications: For the treatment of infections caused by susceptible bacteria. Mechanism of Action: The bactericidal activity of cefepime derives from its affinity for penicillin-binding proteins (PBPs), thereby inhibiting cell wall synthesis.
...It exhibits strong resistance to penicillinase activity, acting as both a competitive and non-competitive inhibitor of penicillinase...It does not inhibit the breakdown of penicillin G by staphylococcal penicillinase. Cephalosporin C and its semi-synthetic analogues can induce penicillinase synthesis in Bacillus cereus and Staphylococcus aureus. /Cephalosporin C/
...An enzyme that specifically acts on cephalosporin C and disrupts its antibacterial activity. This substance, cephalosporinase, is also a β-lactamase. Most such enzymes also possess penicillinase activity; some microorganisms produce a β-lactamase that can act on both penicillin and cephalosporins. /Cephalosporin C/
Bactericidal effect; its action depends on reaching and binding to penicillin-binding proteins located on the bacterial cell membrane; cephalosporin drugs inhibit bacterial septum and cell wall synthesis by acylating membrane-bound transpeptidases. This prevents the cross-linking of peptidoglycan chains, which is crucial for the strength and rigidity of the bacterial cell wall. Furthermore, cell division and growth are inhibited, and susceptible bacteria often lyse and elongate. Rapidly dividing bacteria are most sensitive to cephalosporins. /Cephalosporins/

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Therapeutic Uses
Cephalosporins
For patients who cannot tolerate penicillin, cephalosporins remain an effective alternative for treating a variety of infections. These include streptococcal and staphylococcal infections.
Bacteria sensitive to cefotaxime (Gram-positive and Gram-negative bacteria) are sensitive to cefepime in roughly the same concentration range. Cefepime has a stronger inhibitory effect on group A streptococci and pneumococci than cefotaxime.
Cefepime is one of the newest semi-synthetic cephalosporins. As with other cephalosporins, cefepime should only be used in cases where the patient is sensitive to cefepime and is allergic to penicillin.
For more complete data on the therapeutic uses of cefepime (10 in total), please visit the HSDB record page.

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Drug Warnings
Because cefepime is administered in sodium form, high doses should be used with caution in patients with impaired excretion of this cation. ...Infections may occur with the use of this type of antibiotic, usually caused by Gram-negative bacteria.
The typical dosing regimen for most cephalosporins...must be adjusted for patients with impaired renal function. /Cephalosporins/
...Hypersensitivity to cephalosporins is more common in patients with a history of allergy to penicillin. This appears to be related to sensitization to the β-lactam ring shared by both drugs. /Cephalosporins/
...Enterococcal endocarditis cannot be cured with cephalosporins, even when used concomitantly with gentamicin or streptomycin. ...Enterobacterial (aerobic) infections are often resistant to these cephalosporins. /Cephalosporins/
For more complete data on drug warnings for cefepime (10 in total), please visit the HSDB records page.

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Pharmacodynamics
Cefepime is a first-generation cephalosporin with broad-spectrum antibacterial activity against both Gram-positive and Gram-negative bacteria. Cefepime is more resistant to β-lactamases than penicillin, therefore it is effective against Staphylococcus aureus, but ineffective against methicillin-resistant Staphylococcus aureus (MRSA).

C17H17N3O6S2

423.458

423.056

21593-23-7

Cephapirin sodium;24356-60-3

30699

Typically exists as solid at room temperature

6.98E-26mmHg at 25°C

1.253

2

9

8

28

707

2

CC(OCC1=C(N2C([C@@H](NC(CSC3=CC=NC=C3)=O)[C@H]2SC1)=O)C(O)=O)=O

UQLLWWBDSUHNEB-CZUORRHYSA-N

InChI=1S/C17H17N3O6S2/c1-9(21)26-6-10-7-28-16-13(15(23)20(16)14(10)17(24)25)19-12(22)8-27-11-2-4-18-5-3-11/h2-5,13,16H,6-8H2,1H3,(H,19,22)(H,24,25)/t13-,16-/m1/s1

(6R,7R)-3-(acetyloxymethyl)-8-oxo-7-[(2-pyridin-4-ylsulfanylacetyl)amino]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

Cefapirine; Cephapirin; Cefapirin

2934.99.9001

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)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

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.)