Bacterial cell wall synthesis; β-lactam
Bacterial cell wall synthesis via binding to penicillin-binding proteins (PBPs) located inside the bacterial cell wall, thereby inhibiting the cross-linking of the peptidoglycan layer.

In vitro, cefetamet shows excellent antibacterial activity against major respiratory pathogens, including Streptococcus pneumoniae, Haemophilus influenzae (including beta-lactamase-producing strains), Moraxella catarrhalis, and Group A beta-hemolytic streptococci. It is also active against Neisseria gonorrhoeae and Enterobacteriaceae. However, it has weaker activity against penicillin-resistant S. pneumoniae and is not active against staphylococci or Pseudomonas species.

Cefetamet pivoxil is an oral third-generation cephalosporin that is hydrolyzed in vivo to release the active moiety, cefetamet. Cefetamet demonstrates excellent in vitro activity against major respiratory pathogens, including Streptococcus pneumoniae, Haemophilus influenzae, Moraxella (Branhamella) catarrhalis, and group A beta-hemolytic streptococci. It is active against beta-lactamase-producing strains of H. influenzae and M. catarrhalis, but exhibits poor activity against penicillin-resistant S. pneumoniae. Cefetamet shows marked activity against Neisseria gonorrhoeae and possesses a broad spectrum of activity against Enterobacteriaceae. Staphylococci and Pseudomonas species are resistant to cefetamet.
Cefetamet pivoxil has been investigated for the treatment of both upper and lower community-acquired respiratory tract infections and has demonstrated efficacy equivalent to several established agents, including cefaclor, amoxicillin, and cefixime. In patients with group A beta-hemolytic streptococcal pharyngotonsillitis, a 7-day course of cefetamet pivoxil was as effective as a 10-day course of the standard agent, phenoxymethylpenicillin. In complicated urinary tract infections, cefetamet pivoxil showed similar efficacy to cefadroxil, cefaclor, and cefuroxime axetil. Cefetamet pivoxil was also effective in the treatment of otitis media, pneumonia, pharyngotonsillitis, and urinary tract infections in children. Preliminary data indicate that a single dose of cefetamet pivoxil can effectively eradicate N. gonorrhoeae in both men and women.
The tolerability profile of cefetamet pivoxil is similar to that of other oral cephalosporins, with gastrointestinal effects being the most commonly reported adverse events. To date, no symptoms of carnitine deficiency have been reported with cefetamet pivoxil. Cefetamet pivoxil offers an effective oral alternative for the outpatient management of community-acquired respiratory tract infections, with the advantages of enhanced activity against H. influenzae and increased stability against beta-lactamases. However, its use in regions with a high prevalence of penicillin-resistant S. pneumoniae may be limited. Cefetamet pivoxil is also effective in treating urinary tract infections, although further trials are needed to establish any comparative advantages over other oral agents.

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In vivo, the oral prodrug cefetamet pivoxil is hydrolyzed to release the active cefetamet. It has been studied for treating community-acquired upper and lower respiratory tract infections. In clinical trials, it has shown comparable efficacy to standard drugs like cefaclor, amoxicillin, and cefixime. For pharyngotonsillitis, a 7-day course was as effective as a 10-day course of penicillin V. It is also effective in pediatric otitis media, pneumonia, and urinary tract infections.

A standard non-cellular assay for cephalosporins is the determination of the MIC (Minimum Inhibitory Concentration) in a growth medium. First, solutions of cefetamet are prepared in Mueller-Hinton broth using a two-fold serial dilution method in a 96-well microtiter plate. A bacterial suspension, adjusted to a 0.5 McFarland standard, is then added to each well. The plate is incubated overnight at 35degC, and the MIC is read as the lowest concentration of the antibiotic that completely inhibits visible bacterial growth.

To determine the in vitro susceptibility, a standardized broth microdilution method is used as described. For killing curve assays, a bacterial culture at a specific log-phase is treated with different concentrations of cefetamet (e.g., 0.25×, 1×, 4×, and 8× the MIC). Aliquots are taken at defined time points (e.g., 0, 2, 4, 6, and 24 hours), serially diluted, and plated on nutrient agar. After an overnight incubation, the number of colony-forming units (CFU) is counted to evaluate the bactericidal activity over time.

In a typical animal efficacy model, a murine septicemia or thigh infection model is used. For a respiratory infection model, mice are infected intranasally with a known bacterial pathogen. The prodrug, cefetamet pivoxil, is administered orally to the mice at various doses, starting a few hours post-infection. After a treatment period (e.g., 3 days), animals are sacrificed. Bacterial counts in target organs (e.g., lungs) are determined by plating serial dilutions of homogenized tissue. The effective dose (e.g., ED₅0) required to reduce bacterial load by 50% is then calculated.

Cefetamet is the active form of the oral prodrug. PK data is available for the orally administered cefetamet pivoxil. Following oral administration, the prodrug is rapidly absorbed and hydrolyzed. The absolute bioavailability of cefetamet is approximately 40-50%. The time to peak plasma concentration (Tmax) is about 2-3 hours. The elimination half-life ranges from 2.3 to 2.7 hours. The drug is primarily excreted unchanged in urine via both glomerular filtration and tubular secretion.

5489410 rat LD50 subcutaneous >2 gm/kg SENSE ORGANS AND SPECIAL SENSES: OTHER CHANGES: OLFACTION; SENSE ORGANS AND SPECIAL SENSES: MYDRIASIS (PUPILLARY DILATION): EYE; KIDNEY, URETER, AND BLADDER: OTHER CHANGES Yakuri to Chiryo. Pharmacology and Therapeutics., 18(Suppl
5489410 dog LD oral >1 gm/kg Gekkan Yakuji. Pharmaceuticals Monthly., 35(803), 1993
5489410 rat LD50 oral >2 gm/kg SENSE ORGANS AND SPECIAL SENSES: OTHER CHANGES: OLFACTION; SENSE ORGANS AND SPECIAL SENSES: MYDRIASIS (PUPILLARY DILATION): EYE; KIDNEY, URETER, AND BLADDER: OTHER CHANGES Yakuri to Chiryo. Pharmacology and Therapeutics., 18(Suppl

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The tolerance profile of cefetamet pivoxil (the prodrug) is generally similar to that of other oral cephalosporins. The most commonly reported adverse events are gastrointestinal, including diarrhea, nausea, abdominal pain, and vomiting. Hypersensitivity reactions, such as skin rash, can occur. No reports of carnitine deficiency have been associated with its use.

[1]. Cefetamet pivoxil. A review of its antibacterial activity, pharmacokinetic properties and therapeutic use. Drugs. 1993;45(4):589-621.

Cefetamet is a cephalosporin compound with a methyl group and a [(2Z)-2-(2-amino-1,3-thiazolyl-4-yl)-2-(methoxyimino)acetyl]amino side group; it is a cephalosporin antibiotic effective against Neisseria gonorrhoeae. Cefetamet is a semi-synthetic, β-lactamase-stabilized third-generation cephalosporin with antibacterial activity. Cefetamet binds to and inactivates penicillin-binding proteins (PBPs) located on the inner membrane of the bacterial cell wall. PBPs are enzymes involved in the final stages of bacterial cell wall assembly and in remodeling the cell wall 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 weakening of the bacterial cell wall and ultimately cell lysis.

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This is an approved antibiotic in many countries, often administered as the pivoxil ester (cefetamet pivoxil hydrochloride) to improve oral absorption. This prodrug strategy enhances its lipophilicity. The compound is also used as an EP impurity standard for cefotaxime sodium. Its mechanism of action is standard for beta-lactam antibiotics.

C14H15N5O5S2

397.43

397.051

C, 42.31; H, 3.80; N, 17.62; O, 20.13; S, 16.13

65052-63-3

Cefetamet pivoxil hydrochloride;111696-23-2;Cefetamet hydrochloride;724438-16-8; 65052-63-3; 65243-25-6 (sodium); 65243-33-6 (pivoxil)

5487888

White to off-white solid powder

1.8±0.1 g/cm3

1.821

1.18

3

10

5

26

712

2

O=C(C(N12)=C(C)CS[C@]2([H])[C@H](NC(/C(C3=CSC(N)=N3)=N\OC)=O)C1=O)O

MQLRYUCJDNBWMV-GHXIOONMSA-N

InChI=1S/C14H15N5O5S2/c1-5-3-25-12-8(11(21)19(12)9(5)13(22)23)17-10(20)7(18-24-2)6-4-26-14(15)16-6/h4,8,12H,3H2,1-2H3,(H2,15,16)(H,17,20)(H,22,23)/b18-7-/t8-,12-/m1/s1

(6R,7R)-7-[[(2Z)-2-(2-amino-1,3-thiazol-4-yl)-2-methoxyiminoacetyl]amino]-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid

cefetamet; 65052-63-3; Cefetametum; Deacetoxycefotaxime; LY097964;

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)

DMSO : 25 mg/mL (62.90 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (6.29 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (6.29 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
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.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (6.29 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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