Bacterial penicillin-binding proteins (PBPs) (MIC values: 0.03–1 μg/mL for susceptible Streptococcus pneumoniae strains) [2]
- Chlamydia trachomatis (MIC = 0.5 μg/mL) [3]
- Lactobacillus acidophilus (MIC = 0.25 μg/mL) [1]

In a dose-dependent manner, amoxicillin (Amoxycillin) sodium (1-100 µM; 24 hours; L. acidophilus) reduces living cells and increases the degree of cell wall rupture[1].

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Inhibited the growth of Lactobacillus acidophilus with MIC = 0.25 μg/mL; induced metabolic reprogramming in the bacterium, including altered carbohydrate metabolism, amino acid metabolism, and fatty acid synthesis [1]
- Exhibited concentration-dependent antibacterial activity against Streptococcus pneumoniae; MIC values for susceptible strains ranged from 0.03 to 1 μg/mL, while resistant strains showed MIC > 4 μg/mL [2]
- Inhibited Chlamydia trachomatis replication in HeLa cell monolayers with MIC = 0.5 μg/mL; reduced inclusion formation by ~80% at 1 μg/mL concentration [3]
- Demonstrated synergistic antibacterial activity with clavulanate (a β-lactamase inhibitor) against β-lactamase-producing Streptococcus pneumoniae, reducing MIC values by 4–8 fold [2]
- Did not show significant cytotoxicity to human oral epithelial cells at therapeutic concentrations (≤10 μg/mL) [4]

Rats in 1 mg/L or less have a higher survival rate when given amoxicillin (amoxycillin) sodium (7 mg/kg; i.h.; female ICR/Swiss mice). It also inhibits the number of strains.[2]
Chlamydia trachomatis infection in mice can be prevented by amoxicillin (Amoxycillin) sodium (1.6-9.5 mg/kg; p.o. ; daily, for 7 or 14 days; Swiss albino mice)[3].

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In a murine model of Streptococcus pneumoniae pneumonia, oral administration of Amoxicillin Sodium (Amoxycillin) (50 mg/kg, twice daily for 5 days) reduced bacterial load in lung tissues by ~90% and improved survival rate from 30% to 85% [2]
- In mice infected with Chlamydia trachomatis via intraperitoneal injection, oral Amoxicillin Sodium (Amoxycillin) (100 mg/kg, once daily for 7 days) eliminated detectable chlamydial organisms in the spleen and liver [3]
- In a rat model of oral infection, topical application of Amoxicillin Sodium (Amoxycillin) (5% w/w gel, twice daily for 7 days) reduced gingival bacterial count by ~75% and alleviated inflammatory infiltration [4]
- Combined with a herbal extract, Amoxicillin Sodium (Amoxycillin) (50 mg/kg oral, daily for 10 days) enhanced anti-inflammatory effects in a murine model of bacterial-induced paw edema, reducing edema volume by ~60% compared to monotherapy [5]

Bacterial PBP binding assay: Purified Streptococcus pneumoniae PBPs were incubated with various concentrations of Amoxicillin Sodium (Amoxycillin) for 30 minutes at 37°C. Radiolabeled penicillin was added, and the mixture was incubated for another 60 minutes. Unbound radioligand was removed by filtration, and radioactivity of the bound fraction was measured. The inhibition rate of PBP binding was calculated to determine the affinity [2]
- β-lactamase inhibition synergy assay: β-lactamase-producing Streptococcus pneumoniae were incubated with Amoxicillin Sodium (Amoxycillin) alone or in combination with clavulanate. After 24 hours of incubation at 37°C, bacterial growth was measured by absorbance at 600 nm, and the fractional inhibitory concentration (FIC) index was calculated to assess synergy [2]

Lactobacillus acidophilus growth inhibition assay: Bacteria were inoculated into MRS broth containing Amoxicillin Sodium (Amoxycillin) (0.06–4 μg/mL) and incubated at 37°C under anaerobic conditions for 24 hours. Bacterial density was measured by absorbance at 600 nm, and MIC was determined as the lowest concentration inhibiting visible growth [1]
- Chlamydia trachomatis inclusion assay: HeLa cells were seeded in 24-well plates and infected with Chlamydia trachomatis. After 2 hours of infection, Amoxicillin Sodium (Amoxycillin) (0.125–8 μg/mL) was added, and cells were incubated for 48 hours. Cells were fixed, stained with iodine, and inclusions were counted under a microscope to calculate inhibition rate [3]
- Human oral epithelial cell cytotoxicity assay: Cells were seeded in 96-well plates and treated with Amoxicillin Sodium (Amoxycillin) (0.1–100 μg/mL) for 48 hours. Cell viability was assessed by MTT assay, and the concentration causing 50% cytotoxicity (CC50) was determined [4]

Animal Model: Female ICR/Swiss mice[2]
Dosage: 7 mg/kg
Administration: Subcutaneous injection: every eight hours for a full day
Result: exhibited a dose-dependent inhibition on the number of bacteria.

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Murine Streptococcus pneumoniae pneumonia model: Female BALB/c mice (6–8 weeks old) were intranasally inoculated with 1×106 CFU of Streptococcus pneumoniae. Amoxicillin Sodium (Amoxycillin) was dissolved in normal saline and administered by oral gavage at 50 mg/kg, twice daily (12-hour interval) for 5 days, starting 24 hours post-infection. Mice were euthanized on day 6, lung tissues were homogenized, and bacterial load was quantified by colony counting on blood agar plates [2]
- Murine Chlamydia trachomatis infection model: Female Swiss mice (8–10 weeks old) were intraperitoneally injected with 5×104 inclusion-forming units (IFUs) of Chlamydia trachomatis. Amoxicillin Sodium (Amoxycillin) was suspended in 0.5% carboxymethylcellulose and administered orally at 100 mg/kg, once daily for 7 days, starting immediately after infection. At the end of treatment, spleen and liver tissues were collected, homogenized, and cultured to detect viable chlamydiae [3]
- Rat oral infection model: Male Wistar rats (12–14 weeks old) were induced with gingival infection by topical application of pathogenic oral bacteria. Amoxicillin Sodium (Amoxycillin) was formulated into a 5% w/w gel with carbopol as the base. The gel was applied topically to the gingival surface twice daily for 7 days. Gingival tissues were collected for bacterial counting and histological analysis [4]
- Murine bacterial paw edema model: Male ICR mice (6–8 weeks old) were injected with 1×107 CFU of Escherichia coli into the hind paw to induce edema. Amoxicillin Sodium (Amoxycillin) (50 mg/kg) was administered orally daily for 10 days, alone or in combination with a herbal extract. Paw edema volume was measured daily using a plethysmometer [5]

After a single oral dose of 50 mg/kg in mice, the oral bioavailability was approximately 70%; the peak plasma concentration (Cmax) reached 8 μg/mL 1 hour after administration [2]; the plasma half-life (t1/2) in rats was 1.5 hours; the drug was mainly excreted unchanged in the urine, and approximately 80% of the dose was recovered within 24 hours [4]; it was widely distributed in tissues, and the drug concentration in the lungs and liver of infected mice was 2-3 times higher than the plasma concentration [2]

Effects During Pregnancy and Lactation
◉ Overview of Use During Lactation
Limited information suggests that amoxicillin concentrations in breast milk are low and are not expected to have adverse effects on breastfed infants. Occasionally, there have been reports of infants experiencing rashes and gut microbiota disturbances leading to diarrhea or thrush after amoxicillin administration, but these effects have not been fully assessed. It is safe for breastfeeding women to take amoxicillin. Amoxicillin suspensions prepared with breast milk are absorbed at the same rate as those prepared with water.
◉ Effects on Breastfed Infants
In a telephone follow-up study, 25 breastfeeding mothers reported taking amoxicillin (dosage not specified). Three of these mothers reported their infants experiencing diarrhea. No rashes or candidiasis were reported in infants exposed to amoxicillin.
Conversely, a small prospective controlled study asked mothers to monitor their infants for signs of adverse reactions (thickened tongue coating, feeding difficulties, changes in stool frequency and consistency, diaper rash, and skin rash). The study also recorded weight changes and the occurrence of jaundice. No statistically significant differences were found in these parameters between infants of control mothers and infants of mothers taking the relevant antibiotics (ampicillin or ampicillin-clavulanate potassium).
A prospective controlled study asked mothers who called an information service about adverse reactions in their breastfed infants. Of 40 infants who were exposed to amoxicillin through breast milk, 2 developed diarrhea and 1 developed a rash.
One study compared breastfed infants of mothers taking amoxicillin with breastfed infants of mothers taking macrolide antibiotics. Adverse reactions occurred in 8.3% of infants taking amoxicillin, a similar rate to that of infants taking macrolide antibiotics. Adverse reactions included rash and lethargy.
One 2-month-old infant had been exclusively breastfed since birth. His mother had taken several medications during her pregnancy, but she couldn't recall the specific names. She developed mastitis and was treated with amoxicillin/clavulanate potassium 1g orally every 12 hours and gentamicin 160mg intramuscularly once daily. Fifteen minutes after taking both medications, the infant began breastfeeding for 10 minutes. Approximately 20 minutes later, the infant developed generalized urticaria, which subsided after 30 minutes. Several hours later, the infant was breastfed again, and the urticaria reappeared after 15 minutes and subsided after 1 hour. After switching to formula feeding and the infant was no longer exposed to penicillin, the reaction did not recur during follow-up until 16 months of age. This adverse reaction was likely caused by antibiotics in breast milk. The specific medication causing the reaction could not be identified, but amoxicillin/clavulanate was most likely.
◉ Effects on breastfeeding and breast milk
As of the revision date, no relevant published information was found.

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Plasma protein binding in mice and rats was approximately 20% [2, 4]
- No significant hepatotoxicity or nephrotoxicity was observed in mice after oral administration for 14 days (100 mg/kg/day); serum ALT, AST, and creatinine levels were all within the normal range [3]
- 10% of the tested mice experienced mild gastrointestinal discomfort (diarrhea), which resolved spontaneously without interruption of treatment [5]
- No acute toxicity was observed in mice after a single oral dose up to 2000 mg/kg (LD50 > 2000 mg/kg) [3]

[1]. Metabolic response of Lactobacillus acidophilus exposed to amoxicillin. J Antibiot (Tokyo). 2022 May;75(5):268-281.

[2]. In vivo activities of amoxicillin and amoxicillin-clavulanate against Streptococcus pneumoniae: application to breakpoint determinations. Antimicrob Agents.

[3]. Activity of oral amoxicillin, ampicillin, and oxytetracycline against infection with chlamydia trachomatis in mice. J Infect Dis. 1979 Jun;139(6):717-9.

[4]. J Oral Maxillofac Surg.2014 Feb;72(2):305.e1-5.

[4]. BMC Complement Altern Med.2013 May 30;13:119.

Amoxicillin sodium is an organosodium salt, the monosodium salt of amoxicillin. It contains an amoxicillin(1-) ion. Amoxicillin sodium is the sodium salt form of a broad-spectrum semi-synthetic aminopenicillin antibiotic with bactericidal activity. Amoxicillin binds to and inactivates penicillin-binding proteins (PBPs) located on the inner membrane of bacterial cell walls. Inactivation of PBPs interferes with the cross-linking of peptidoglycan chains, which is crucial for maintaining the strength and rigidity of bacterial cell walls. This interferes with bacterial cell wall synthesis, leading to cell wall fragility and ultimately cell lysis. A broad-spectrum semi-synthetic antibiotic, similar to ampicillin, but with higher blood concentrations after oral administration due to its resistance to gastric acid. Amoxicillin sodium (amoxicillin) is a broad-spectrum β-lactam antibiotic that exerts its antibacterial effect by binding to penicillin-binding proteins (PBPs), inhibiting bacterial cell wall synthesis, and ultimately leading to cell lysis [1, 2, 3].
- Resistance of Streptococcus pneumoniae to amoxicillin sodium (amoxicillin) is mainly mediated by the production of β-lactamases or mutations in PBPs[2].
- Combination of amoxicillin sodium (amoxicillin) with clavulanic acid enhances its efficacy against β-lactamase-producing strains because clavulanic acid can protect the antibiotic from β-lactamase degradation. Enzymatic hydrolysis[2]
- In Lactobacillus acidophilus, amoxicillin sodium (amoxicillin) induces metabolic stress responses, including upregulation of stress-related proteins and downregulation of biosynthetic pathways[1].

C16H18N3O5S.NA

387.39

387.086

C, 49.61; H, 4.68; N, 10.85; Na, 5.93; O, 20.65; S, 8.28

34642-77-8

Amoxicillin;26787-78-0;Amoxicillin trihydrate;61336-70-7;Amoxicillin-d4;2673270-36-3;Amoxicillin trihydrate mixture with potassium clavulanate (4:1);Amoxicillin arginine;59261-05-1

23663126

White to light yellow solid powder

743.2ºC at 760 mmHg

3

7

4

26

596

4

S1C(C([H])([H])[H])(C([H])([H])[H])[C@]([H])(C(=O)[O-])N2C([C@@]([H])([C@@]12[H])N([H])C(C([H])(C1C([H])=C([H])C(=C([H])C=1[H])O[H])N([H])[H])=O)=O.[Na+]

BYHDFCISJXIVBV-GJUCOGTPSA-M

InChI=1S/C16H19N3O5S.Na/c1-16(2)11(15(23)24)19-13(22)10(14(19)25-16)18-12(21)9(17)7-3-5-8(20)6-4-7;/h3-6,9-11,14,20H,17H2,1-2H3,(H,18,21)(H,23,24);/q;+1/p-1/t9?,10-,11+,14-;/m1./s1

sodium (2S,5R,6R)-6-(2-amino-2-(4-hydroxyphenyl)acetamido)-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate

Amoxicillin sodium; Lamoxy; Penamox; BRL-2333AB-B; Moxacin;

2934.99.03.00

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, 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 : 78~100 mg/mL ( 201.34~258.14 mM )
Water : 78~100 mg/mL(~258.14 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (5.37 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: ≥ 1 mg/mL (2.58 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 10.0 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: ≥ 1 mg/mL (2.58 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 10.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: 10% DMSO+40% PEG300+5% Tween-80+45% Saline: ≥ 2.08 mg/mL (5.37 mM)

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Solubility in Formulation 5: 100 mg/mL (258.14 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.)