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

Rat survival rates are increased when rats are given amoxicillin (Amoxycillin) at a dose of 7 mg/kg (i.h.; female ICR/Swiss mice) and strain numbers are inhibited[2].
Swiss albino mice given amoxicillin (also known as amoxycillin) (1.6–9.5 mg/kg; p.o.; daily, for 7 or 14 days) are protected against chlamydia trachomatis infection[3].

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.

Absorption, Distribution and Excretion
The bioavailability of amoxicillin is approximately 60%. After oral administration of 250 mg amoxicillin, the peak plasma concentration (Cmax) is 3.93 ± 1.13 mg/L, the time to peak concentration (Tmax) is 1.31 ± 0.33 h, and the area under the curve (AUC) is 27.29 ± 4.72 mg·h/L. After oral administration of 875 mg amoxicillin, the peak plasma concentration (Cmax) is 11.21 ± 3.42 mg/L, the time to peak concentration (Tmax) is 1.52 ± 0.40 h, and the area under the curve (AUC) is 55.04 ± 12.68 mg·h/L. From 125 mg to 1 g of amoxicillin, 70-78% is excreted in the urine after 6 hours. The central volume of distribution of amoxicillin is 27.7 L. The mean clearance rate of amoxicillin is 21.3 L/h. A 48-year-old woman was admitted to the hospital with pneumococcal meningitis. After four days of treatment with a high dose of amoxicillin (320 mg/kg/day), she developed acute oliguric renal failure, and amoxicillin crystals were confirmed by infrared spectroscopy. Her condition improved after gradually reducing the amoxicillin dose, undergoing one hemodialysis session, and further fluid resuscitation. Amoxicillin is primarily excreted unchanged in the urine. Amoxicillin readily diffuses into most body tissues and fluids, except for cerebrospinal fluid, except in cases of meningitis. In serum, the protein binding rate of amoxicillin is approximately 20%. Therapeutic concentrations were found in interstitial fluid after administration of a 1-gram dose using a special skin window technique. Although there are reports that the presence of food in the gastrointestinal tract can reduce and delay peak serum concentrations of amoxicillin, the total absorption of the drug does not appear to be affected. Researchers administered amoxicillin intravenously, orally, and intramuscularly at doses of 250 mg, 500 mg, and 1000 mg to healthy subjects. Serum drug concentrations were analyzed using a two-compartment open model, and the area under the curve (AUC) and urinary recovery were calculated. Changes in these pharmacokinetic parameters were then examined using three-way ANOVA and linear regression equations. Results confirmed that oral absorption was nearly complete: the AUC was 93% of intravenous absorption, and the urinary recovery rate was 86%. Intramuscular amoxicillin achieved complete and reliable absorption, with peak drug concentrations, AUC, and urinary recovery rates comparable to oral administration. After intramuscular administration of lyophilized amoxicillin, the AUC was 92% of intravenous absorption, and the urinary recovery rate was 91%. Peak serum concentrations, time to peak concentration, and other pharmacokinetic parameters were nearly identical with those of oral administration. Both intramuscular and oral administration showed dose-dependent absorption (absorption rate constant of 1.3/hr for the 250 mg dose and 0.7/hr for the 1000 mg dose). This resulted in a relatively late and lower peak serum concentration with increasing dose. However, total absorption was dose-independent, with changes in urinary recovery and AUC of less than 10%. For more complete data on the absorption, distribution, and excretion of amoxicillin (10 in total), please visit the HSDB record page. Metabolites/Metabolites Seven metabolites were detected after incubation with human liver microsomes. Metabolite M1 underwent hydroxylation, M2 underwent oxidative deamination, M3 through M5 underwent aliphatic chain oxidation, M6 underwent decarboxylation, and M7 underwent glucuronidation. Biological Half-Life The half-life of amoxicillin is 61.3 minutes.

Hepatotoxicity
Rare, specific cases of liver injury have been reported in patients taking aminopenicillin antibiotics, including amoxicillin. These cases are characterized by short incubation periods, ranging from a few days to two weeks. Liver injury can occur after discontinuation of the antibiotic. Serum enzyme profiles associated with aminopenicillin-induced liver injury include hepatocellular types, characterized by significantly elevated ALT and AST, and mildly elevated alkaline phosphatase, which rapidly recovers after discontinuation of the drug. Additionally, cholestatic liver injury has been reported, characterized by significantly elevated alkaline phosphatase (similar to penicillin-induced liver injury), some of which are associated with persistent cholestasis (Case 1). Liver injury may be accompanied by signs or symptoms of hypersensitivity reactions, such as eosinophilia, rash, and arthralgia, and in some cases, toxic epidermal necrolysis or Stevens-Johnson syndrome. Typical cholestatic hepatitis following amoxicillin combined with clavulanate potassium treatment is more common than liver injury caused by amoxicillin alone. In fact, this combination therapy is currently the most common cause of specific acute liver injury in the United States, Europe, and Australia. However, this injury is usually attributed to clavulanate potassium rather than amoxicillin. Clinical presentations are similar but may not be identical. In cases of suspected amoxicillin-induced liver injury, extra care should be taken to confirm that the patient is not taking amoxicillin-clavulanate potassium (Augmentin).
Probability Score: B (Very likely but rare, a clinically significant cause of liver injury).

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Use during pregnancy and lactation
◉ Overview of use during lactation
Limited information suggests that the concentration of amoxicillin in breast milk is low and is not expected to have adverse effects on breastfed infants. Occasionally, there have been reports of rashes and gastrointestinal flora disturbances in infants after taking amoxicillin, leading to diarrhea or thrush, but these adverse reactions have not been adequately evaluated. It is safe for breastfeeding women to take amoxicillin. Amoxicillin suspension mixed with breast milk is absorbed at the same rate as amoxicillin powder mixed 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.
In contrast, 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 rashes). Weight changes and the occurrence of jaundice were also recorded. 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 exposed to amoxicillin through breast milk, 2 experienced diarrhea and 1 developed a rash.
One study compared infants breastfed by mothers taking amoxicillin with infants breastfed by mothers taking macrolide antibiotics. In infants exposed to amoxicillin, 8.3% experienced adverse reactions, similar to the incidence in infants exposed to macrolide antibiotics. Adverse reactions included rash and drowsiness. A two-month-old infant, who had been exclusively breastfed since birth, was treated with amoxicillin/clavulanate potassium 1g orally every 12 hours and gentamicin 160mg intramuscularly once daily. Fifteen minutes after the first dose of both medications, the infant began breastfeeding for 10 minutes. Approximately 20 minutes later, the infant developed a generalized urticaria, which subsided after 30 minutes. Several hours later, the infant breastfed again, and the urticaria recurred after 15 minutes, disappearing after an hour. After switching to formula feeding and being no longer exposed to penicillin, the infant was followed up until 16 months of age without recurrence of the reaction. This adverse reaction was most likely caused by antibiotics in breast milk. The causative drug could not be identified, but amoxicillin/clavulanate was most likely.
◉ Effects on lactation and breast milk
As of the revision date, no relevant published information was found.

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Protein binding
Amoxicillin has a protein binding rate of 17% in serum.

[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 Chemother. 1998 Sep;42(9):2375-9.

[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]. Amoxicillin, a new penicillin antibiotic. Antimicrob Agents Chemother. 1973 Feb;3(2):262-5.

[5]. Introduction: historical perspective and development of amoxicillin/clavulanate. Int J Antimicrob Agents. 2007 Dec;30 Suppl 2:S109-12.

Amoxicillin is a penicillin with a 2-amino-2-(4-hydroxyphenyl)acetamido group at the 6-position of the penicillin ring. It is an antibacterial drug. It is both a penicillin and a penicillin allergen. It is the conjugate acid of amoxicillin (1-). Amoxicillin is a prescription antibacterial drug approved by the U.S. Food and Drug Administration (FDA) for the treatment of certain bacterial infections, such as community-acquired pneumonia; ear, nose, and throat infections; genitourinary tract infections; and skin and respiratory tract infections. Community-acquired pneumonia is a bacterial respiratory disease and may be an opportunistic infection (OI) of HIV. Amoxicillin, or BRL-2333, is a penicillin G derivative first reported in the literature in 1972. Amoxicillin has similar activity to penicillin and ampicillin, but its serum concentration is higher than that of ampicillin. Amoxicillin was approved by the FDA on January 18, 1974. Anhydrous amoxicillin is a penicillin-type antibacterial drug. It has been reported that amoxicillin exists in Arundo donax and Apis cerana, and relevant data exist. Amoxicillin is a broad-spectrum semi-synthetic aminopenicillin antibiotic with bactericidal activity. Amoxicillin binds to and inactivates penicillin-binding protein (PBP) 1A located on the inner membrane of bacterial cell walls. Inactivation of PBP interferes with the cross-linking of peptidoglycan chains, which is crucial for maintaining the strength and rigidity of bacterial cell walls. This interrupts bacterial cell wall synthesis, leading to reduced cell wall strength and ultimately cell lysis. Anhydrous amoxicillin is the anhydrous form of a broad-spectrum semi-synthetic aminopenicillin antibiotic with bactericidal activity. Amoxicillin binds to and inactivates penicillin-binding protein (PBP) located on the inner membrane of bacterial cell walls. Inactivation of PBP 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 acid-resistant properties. Drug Indications Amoxicillin, used alone, is indicated for the treatment of infections caused by susceptible bacteria in the ear, nose, throat, genitourinary tract, skin, soft tissues, and lower respiratory tract. Amoxicillin in combination with carvedic acid is indicated for the treatment of acute bacterial sinusitis, community-acquired pneumonia, lower respiratory tract infections, acute bacterial otitis media, skin and soft tissue infections, and urinary tract infections. Amoxicillin in combination with omeprazole is indicated for the treatment of Helicobacter pylori (H. pylori) infection. Amoxicillin, when used in combination with vonoprazan and clarithromycin, constitutes triple therapy; or when used in combination with vonoprazan, constitutes dual therapy, for the treatment of Helicobacter pylori infection in adults.
FDA Label
Treatment of Helicobacter pylori Infection
Treatment of Helicobacter pylori Infection

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Mechanism of Action
Amoxicillin competitively inhibits penicillin-binding protein 1 and other high-molecular-weight penicillin-binding proteins. Penicillin-binding proteins are responsible for glycosyltransferase and transpeptidase reactions, leading to D-alanine and D-aspartate cross-linking in the bacterial cell wall. Without the action of penicillin-binding proteins, bacteria overexpress autolysins and are unable to build and repair their cell walls, resulting in bactericidal effects.
Penicillins and their metabolites are potent immunogens because they can bind to proteins and act as haptens to trigger acute antibody-mediated immune responses. The most common (approximately 95%) or “primary” determinant of penicillin allergy is the penicillin acyl determinant, which is produced by opening the β-lactam ring of penicillin. This allows penicillin to bind to proteins via the amide group. A less common, "minor" determining factor is other formed metabolites, including natural penicillin and penicillinic acid. Amoxicillin, similar to penicillin, has a bactericidal effect on susceptible bacteria during their active reproductive phase. It causes bacterial death by inhibiting cell wall biosynthesis.

C16H25N3O8S

419.44

419.136

C, 45.82; H, 6.01; N, 10.02; O, 30.51; S, 7.64

61336-70-7

Amoxicillin sodium;34642-77-8;Amoxicillin;26787-78-0;Amoxicillin-d4;2673270-36-3;Amoxicillin trihydrate mixture with potassium clavulanate (4:1);Amoxicillin arginine;59261-05-1

33613

Crystals from water

1.54g/cm3

743.2ºC at 760 mmHg Vapour

>200ºC (dec.)

403.3ºC

302 ° (C=0.1, H2O)

0.859

4

7

4

25

590

4

S1C(C([H])([H])[H])(C([H])([H])[H])[C@]([H])(C(=O)O[H])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.O([H])[H].O([H])[H].O([H])[H]

MQXQVCLAUDMCEF-CWLIKTDRSA-N

InChI=1S/C16H19N3O5S.3H2O/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)3*1H2/t9-,10-,11+,14-/m1.../s1

(2S,5R,6R)-6-[[(2R)-2-Amino-2-(4-hydroxyphenyl)acetyl]amino]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid trihydrate

Larotid Amoxil Amoxipen Moxaline AmodexAmoxicillin Trihydrate Amoxicillin 3H2OAmoxicillin Trihydrate; Amoxicillin 3H2O; Larotid; Amoxil; Amoxipen; Moxaline; Amodex;

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 : ~10 mg/mL (~23.84 mM)
H2O : ~2 mg/mL (~4.77 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (4.96 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 2: ≥ 2.08 mg/mL (4.96 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 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 3: ≥ 1 mg/mL (2.38 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 10.0 mg/mL clear DMSO stock solution to 400 μL of PEG300 and mix evenly; then add 50 μL of Tween-80 to the above solution and mix evenly; then add 450 μL of 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 4: 10% DMSO+90% (20% SBE-β-CD in Saline): ≥ 2.08 mg/mL (4.96 mM)

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