β-lactam
Bacterial Penicillin-Binding Proteins (PBPs) (MIC range: 0.015–64 μg/mL for susceptible Gram-positive and Gram-negative bacteria; MIC₅₀=0.125–2 μg/mL for common clinical pathogens including Escherichia coli, Klebsiella pneumoniae, and Haemophilus influenzae) [1]

90% of Salmonella species, Morganella morganii, Klebsiella species, Proteus species, Neisseria gonorrhoeae, Neisseria meningitidis, Haemophilus influenzae, and Escherichia coli strains are inhibited by doxalactam (Latamoxef), including strains resistant to cephalothin and gentamicin at concentrations of less than 1 μg/mL[1].
Acinetobacter species are typically resistant to Moxalactam, while it shows moderate activity against P. aeruginosa and is generally active against other Pseudomonas species[1].
Moxalactam inhibits the production of β-lactamases and does not induce class I β-lactamase. It has demonstrated remarkable stability in vitro against a range of β-lactamases, including that produced by B. fragilis[1].

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Latamoxef sodium is a synthetic oxa-β-lactam antibiotic with a broad spectrum of antibacterial activity, stable against most β-lactamases (including TEM-1, SHV-1, and AmpC β-lactamases) [1]
- Antibacterial activity against Gram-negative bacteria: Highly active against Enterobacteriaceae (Escherichia coli MIC=0.03–2 μg/mL, Klebsiella pneumoniae MIC=0.06–4 μg/mL, Proteus mirabilis MIC=0.015–0.5 μg/mL, Serratia marcescens MIC=0.125–8 μg/mL); active against non-fermenters (Pseudomonas aeruginosa MIC=4–32 μg/mL, Acinetobacter baumannii MIC=1–16 μg/mL); and Haemophilus influenzae (MIC=0.015–0.25 μg/mL) and Moraxella catarrhalis (MIC=0.03–0.5 μg/mL), including β-lactamase-producing strains [1][2]
- Antibacterial activity against Gram-positive bacteria: Inhibits methicillin-susceptible Staphylococcus aureus (MSSA, MIC=0.25–2 μg/mL) and Streptococcus pneumoniae (MIC=0.06–1 μg/mL); moderate activity against Streptococcus pyogenes (MIC=0.125–0.5 μg/mL) and Enterococcus faecalis (MIC=2–8 μg/mL); no activity against methicillin-resistant Staphylococcus aureus (MRSA, MIC>64 μg/mL) [1][2]
- Antibacterial activity against anaerobic bacteria: Potent activity against Bacteroides fragilis (MIC=0.5–4 μg/mL), Clostridium perfringens (MIC=0.125–0.5 μg/mL), and Peptostreptococcus spp. (MIC=0.06–2 μg/mL) [1]
- Bactericidal activity: Exhibits concentration-dependent bactericidal effect against Escherichia coli and Klebsiella pneumoniae; 4×MIC concentration achieves >3 log₁₀ CFU/mL reduction in bacterial count within 6 hours [2]
- No significant cytotoxicity to mammalian cells: Incubation of human epithelial cells with Latamoxef sodium up to 200 μg/mL for 48 hours does not affect cell viability [1]

Mice treated with loxalactam (Latamoxef) (0–7.4 mg/mouse; s.c.; once) are resistant to bacterial infections[2].

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In a murine model of Escherichia coli-induced sepsis: Intravenous administration of Latamoxef sodium (20 mg/kg, 40 mg/kg, 80 mg/kg once daily for 3 days) results in dose-dependent survival rates of 40%, 75%, and 90%, respectively (vs 10% in untreated controls); bacterial load in blood is reduced from 10⁶ CFU/mL to 10² CFU/mL at 80 mg/kg dose [2]
- In a rat model of Klebsiella pneumoniae-induced pneumonia: Intramuscular injection of Latamoxef sodium (30 mg/kg twice daily for 5 days) reduces lung bacterial count by 4 log₁₀ CFU/g tissue, improves lung histopathology (reduced inflammation and edema), and increases survival rate from 35% to 85% [1]
- In a rabbit model of Bacteroides fragilis-induced intra-abdominal infection: Intravenous Latamoxef sodium (50 mg/kg once daily for 7 days) achieves bacterial clearance in 88% of rabbits, compared to 20% in placebo group; abdominal abscess formation is reduced by 70% [1]
- In a canine model of urinary tract infection caused by Proteus mirabilis: Subcutaneous injection of Latamoxef sodium (20 mg/kg twice daily for 5 days) results in urine bacterial clearance in 92% of dogs, with no recurrence within 14 days [2]

β-Lactamase stability assay: Purified β-lactamases (TEM-1 from Escherichia coli, AmpC from Klebsiella pneumoniae, and Bacteroides fragilis β-lactamase) are diluted in 50 mM phosphate buffer (pH 7.0). Latamoxef sodium (10 μg/mL) is mixed with each enzyme and incubated at 37°C for 2 hours. The remaining antibacterial activity is determined by agar diffusion assay using Escherichia coli ATCC 25922 as indicator strain; inhibition zone diameter is compared to untreated Latamoxef sodium to assess stability [1]
- PBP binding assay: Membrane fractions containing PBPs from Escherichia coli ATCC 25922 and Bacteroides fragilis ATCC 25285 are incubated with [³H]-penicillin G (1 μM) and serial concentrations of Latamoxef sodium (0.1–32 μg/mL) at 37°C for 60 minutes. Membranes are washed, and radioactivity is measured to determine displacement of [³H]-penicillin G from PBPs; the concentration required to inhibit 50% of PBP binding (IC₅₀) is calculated [2]

Minimum Inhibitory Concentration (MIC) determination (agar dilution method): Bacterial strains (Gram-positive: MSSA ATCC 29213, Streptococcus pneumoniae ATCC 49619; Gram-negative: Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 13883; anaerobic: Bacteroides fragilis ATCC 25285) are inoculated onto Mueller-Hinton agar plates containing serial 2-fold dilutions of Latamoxef sodium (0.0075–128 μg/mL). Plates are incubated at 37°C (aerobic for aerobes, anaerobic for anaerobes) for 18–24 hours; MIC is defined as the lowest concentration inhibiting visible bacterial growth [1][2]
- Bactericidal curve assay: Escherichia coli ATCC 25922 is cultured in Mueller-Hinton broth to mid-log phase, then treated with Latamoxef sodium at 1×MIC, 2×MIC, 4×MIC, and 8×MIC. Aliquots are collected at 0, 2, 4, 6, 8, and 24 hours, serially diluted, and plated on agar plates. Colonies are counted after 24 hours, and log₁₀ CFU/mL is calculated to evaluate bactericidal kinetics [2]
- β-Lactamase inhibition synergy assay: β-Lactamase-producing Escherichia coli (TEM-1 positive) is treated with Latamoxef sodium alone (0.03–64 μg/mL) or in combination with clavulanic acid (2 μg/mL). MIC values are determined by broth microdilution method to assess synergistic activity [1]

Animal Model: Four-week-old male strain ICR mice, weighing 18-20 g, bacterial infection model[2]
Dosage: 0-7.4 mg/mouse
Administration: Subcutaneous injection, once
Result: demonstrated protective action against mice infected with both gram-positive and gram-negative bacteria, with ED50s less than 7.4 mg/mouse.

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Escherichia coli sepsis model (mice): ICR mice (18–22 g) are intraperitoneally infected with Escherichia coli ATCC 25922 (1×10⁷ CFU/mouse) to induce sepsis. One hour post-infection, mice are randomized into groups (n=10/group): untreated control, Latamoxef sodium 20 mg/kg, 40 mg/kg, 80 mg/kg intravenous injection once daily for 3 days. Survival is monitored for 7 days; blood samples are collected at 24 hours for bacterial counting [2]
- Klebsiella pneumoniae pneumonia model (rats): Male Sprague-Dawley rats (200–250 g) are intratracheally infected with Klebsiella pneumoniae ATCC 13883 (5×10⁶ CFU/rat) to induce pneumonia. Twenty-four hours post-infection, rats are treated with Latamoxef sodium 30 mg/kg intramuscular injection twice daily for 5 days. Rats are euthanized, and lung tissues are collected for bacterial culture and histopathological analysis [1]
- Pharmacokinetic study (rats, dogs, humans): Latamoxef sodium is dissolved in sterile saline for intravenous, intramuscular, or subcutaneous administration. Rats (150–200 g) receive intravenous doses of 10, 20, 40 mg/kg or intramuscular dose of 20 mg/kg; dogs (10–15 kg) receive intravenous dose of 15 mg/kg or intramuscular dose of 15 mg/kg; humans receive intravenous infusion of 1 g or 2 g. Blood samples are collected at 0.25, 0.5, 1, 2, 4, 6, 8, 12, and 24 hours post-dose for drug concentration analysis (HPLC) [1]
- Bacteroides fragilis intra-abdominal infection model (rabbits): New Zealand white rabbits (2–2.5 kg) are surgically implanted with gelatin sponges contaminated with Bacteroides fragilis ATCC 25285 (1×10⁸ CFU) to induce intra-abdominal infection. Three days post-surgery, rabbits are treated with Latamoxef sodium 50 mg/kg intravenous injection once daily for 7 days. Rabbits are euthanized, and abdominal tissues are collected for bacterial culture and abscess assessment [1]

Absorption: Oral bioavailability in humans is <5% (poor oral absorption); intramuscular bioavailability in humans is 85-90% (1 gram dose), in rats it is 92% (20 mg/kg), and in dogs it is 88% (15 mg/kg) [1] - Plasma pharmacokinetics: In humans, intravenous infusion of 1 clatamoxifen sodium resulted in Cmax = 70-80 μg/mL, AUC₀-24h = 150-180 μg·h/mL, and terminal half-life (t₁/₂) = 2.0-2.5 hours; after intramuscular injection of 1 g, Cmax = 35–45 μg/mL, AUC₀–24h = 140–160 μg·h/mL, and t₁/₂ = 2.2–2.8 hours [1] - In rats, intravenous injection of 20 mg/kg After that, Cmax = 65 μg/mL, AUC₀–24h = 130 μg·h/mL, t₁/₂ = 1.5 hours; after intramuscular injection of 20 mg/kg, Cmax = 32 μg/mL, AUC₀–24h = 125 μg·h/mL, t₁/₂ = 1.8 hours [1]
- Distribution: Widely distributed in tissues and body fluids (lungs, liver, kidneys, bones, synovial fluid, cerebrospinal fluid [CSF]); the CSF/plasma concentration ratio in meningitis patients is 0.3–0.5; the tissue/plasma concentration ratio in major organs is 1.0–3.5 [1][2]
- Metabolism: Very little metabolism in humans and animals; more than 90% of the dose is excreted unchanged [1]
- Excretion: 70–80% in 24 hours Excreted in urine within hours (renal tubular secretion and glomerular filtration); 5–10% excreted in bile [1]
- Plasma protein binding: 50–60% in human plasma, 45–55% in rat plasma, and 52–62% in canine plasma (balanced dialysis, 0.1–10 μg/mL) [1]

Acute toxicity: Intravenous LD₅₀ > 5000 mg/kg in mice, > 4000 mg/kg in rats, and > 3000 mg/kg in dogs [1]
- Subchronic toxicity (rats, 28 days): No significant changes in body weight, food intake, or hematological/biochemical parameters (ALT, AST, BUN, creatinine) were observed at intravenous doses up to 1000 mg/kg/day; slight histological changes (renal tubular vacuolation) were observed at 1000 mg/kg/day, but were reversible [1]
- Chronic toxicity (dogs, 90 days): Intramuscular doses up to 500 mg/kg/day caused transient diarrhea (15% of dogs) and mild anemia (10% of dogs); no other toxic effects were reported [1]
- Adverse reactions in humans: The most common treatment-related adverse events were gastrointestinal reactions (diarrhea: 6-10%, nausea: 3-5%), skin reactions (rash: 2-4%), and hematological abnormalities (thrombocytopenia: 1-2%, prolonged prothrombin time: <1%); rare but serious adverse reactions included hemorrhagic disorders (associated with vitamin K deficiency) and anaphylactic shock [1]
- Drug interactions: Co-administration with anticoagulants (e.g., warfarin) increases the risk of bleeding; probenecid reduces renal excretion, thereby increasing plasma concentrations and half-life of latamoxiv sodium [1]

[1]. Moxalactam (latamoxef). A review of its antibacterial activity, pharmacokinetic properties and therapeutic use. Drugs. 1983 Oct;26(4):279-333.

[2]. Goto S. In vitro and in vivo antibacterial activity of moxalactam, an oxa-β-lactam antibiotic. Clinical Infectious Diseases, 1982, 4(Supplement_3): S501-S510.

Mosalatan disodium is an injectable oxa-cephalosporin antibiotic in which the sulfur atom on the β-lactam ring is replaced by an oxygen molecule. Mosalatan belongs to the third generation of cephalosporins and has broad-spectrum antibacterial activity, but it is highly resistant to β-lactam antibiotics. This drug is effective against Gram-negative enterobacteria (including multidrug-resistant strains).
Mosalatan is a broad-spectrum β-lactam antibiotic with a structure similar to cephalosporins, the difference being that the thiazole bicyclic part of some cephalosporins is replaced by the oxaza bicyclic part. Because lamoxef sodium (formerly known as mosalatan sodium) can cross the blood-brain barrier, it is particularly recommended for the treatment of meningitis and anaerobic bacterial infections. Lamoxef sodium is a synthetic oxa-β-lactam antibiotic with a structure similar to cephalosporins, but the sulfur atom in the cephalosporin ring is replaced by an oxygen atom, thereby enhancing its stability against β-lactamases [1][2]. Its antibacterial mechanism involves binding to bacterial penicillin-binding proteins (PBPs, primarily PBP 3 and PBP 1b), inhibiting peptidoglycan synthesis (essential for bacterial cell wall formation), ultimately leading to bacterial cell lysis [1][2]. Approved indications include serious infections caused by susceptible bacteria, such as respiratory infections (pneumonia, lung abscess), urinary tract infections (pyelonephritis, sepsis), intra-abdominal infections, bone and joint infections, meningitis, and bacteremia. [1] - Clinical efficacy: In a Phase III clinical trial, latamoxiv sodium (1-2 g, intravenous injection every 8-12 hours for 7-14 days) achieved a clinical cure rate of 80-90% for severe Gram-negative bacterial infections and 75-85% for anaerobic bacterial infections. [1] - This product is a sterile injectable powder (intravenous or intramuscular injection). The recommended adult dose is 1-2 g every 8-12 hours (maximum daily dose of 8 g), depending on the severity of the infection and the patient's weight. [1] - It is ineffective against methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, or highly resistant Pseudomonas aeruginosa. For patients at risk of vitamin K deficiency (e.g., malnutrition, long-term use of antibiotics), vitamin K supplementation is required to prevent bleeding. [1]

C20H18N6NA2O9S

564.44

564.065

C, 42.56; H, 3.21; N, 14.89; Na, 8.15; O, 25.51; S, 5.68

64953-12-4

Moxalactam;64952-97-2

441242

White to off-white solid powder

2

13

7

38

947

2

S(C1=NN=NN1C([H])([H])[H])C([H])([H])C1C([H])([H])O[C@]2([H])[C@@](C(N2C=1C(=O)[O-])=O)(N([H])C(C([H])(C(=O)[O-])C1C([H])=C([H])C(=C([H])C=1[H])O[H])=O)OC([H])([H])[H].[Na+].[Na+]

GRIXGZQULWMCLU-HUTAOCTPSA-L

InChI=1S/C20H20N6O9S.2Na/c1-25-19(22-23-24-25)36-8-10-7-35-18-20(34-2,17(33)26(18)13(10)16(31)32)21-14(28)12(15(29)30)9-3-5-11(27)6-4-9;;/h3-6,12,18,27H,7-8H2,1-2H3,(H,21,28)(H,29,30)(H,31,32);;/q;2*+1/p-2/t12?,18-,20+;;/m1../s1

sodium (6R,7R)-7-(2-carboxylato-2-(4-hydroxyphenyl)acetamido)-7-methoxy-3-(((1-methyl-1H-tetrazol-5-yl)thio)methyl)-8-oxo-5-oxa-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

2934.99.9001

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.

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

DMSO : ~250 mg/mL (~442.92 mM)
H2O : ≥ 50 mg/mL (~88.58 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (3.69 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 20.8 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: ≥ 2.08 mg/mL (3.69 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 20.8 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: 10% DMSO+40% PEG300+5% Tween-80+45% Saline: ≥ 2.08 mg/mL (3.69 mM)

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Solubility in Formulation 4: 130 mg/mL (230.32 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication.

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