1.What is Amoxicillin?
1.1. Definition
Amoxicillin is a penicillin derivative and a broad-spectrum antibiotic that treats bacterial infections, including respiratory tract (e.g., pneumonia caused by Streptococcus species), urinary tract, nose, ear, throat, and skin infections.
Additionally, it has various off-label uses, including infective endocarditis prophylaxis (a single dose of 3 g ), Lyme disease, and erysipeloid.
Amoxicillin is given alone or other drugs such as clavulanic acid to treat infections as community-acquired pneumonia and bacterial sinusitis or with omeprazole to treat stomach ulcers caused by Helicobacter pylori (H. pylori) infection.
Tablets (immediate-release, extended-release, or chewable), capsules, and powder for oral suspension of amoxicillin are intended for the oral route of administration.
It could also be given intravenously, but it requires medical supervision.
Amoxicillin is one of the most extensively prescribed antibiotics in the primary care setting and the first-line treatment for bacterial infections; however, it is not effective in viral infections such as flu and the common cold.
Amoxicillin was discovered in 1972 by Beecham Research Laboratories (BRL) scientists and was officially approved by FDA in 1974.
1.2. Chemical & Physical Properties
Chemical structure:
Synonyms: Amoxicillin anhydrous, p- Hydroxyampicillin, Amox
Molecular weight: 365.4 g/mol
Molecular formula: C16H19N3O5S
CAS number: 26787-78-0
DrugBank accession number: DB01060
IUPAC Name: (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
Melting point: 194 °C
Storage temperature: Amoxicillin capsules and tablets can be stored at room temperature and kept away from humidity.
The liquid preparation of the drug should be kept refrigerated and must be discarded if it precipitated or discolored. Additionally, Freezing may damage the drug formula.
Powder color: White to off-white
Solubility: Soluble in water (0.958 mg/mL), moderately soluble in ethanol, and poorly soluble in acetone.
The spectrum of activity: gram-positive and gram-negative bacteria
Stability/Shelf Life: Amoxicillin capsules & tablets (2-3 years), amoxicillin suspension (14 days when mixed with water)
1.3. Brand name: Moxil®, Clavulin®, Trimox®
2.Mechanism of action of Amoxicillin
Amoxicillin is a beta-lactam antimicrobial agent that acts via binding to penicillin-binding protein (PBP), located in the inner membrane of the bacterial cell wall.
This results in competitive inhibition of PBP, which is responsible for the cross-linking of D-alanine and D-aspartic acid in the bacterial cell walls.
Eventually, interruption of the cell wall synthesis causes lysis of the cell.
3. Amoxicillin vs. Penicillin
Both amoxicillin and penicillin belong to the same penicillin group of beta-lactam antibiotics, both act via the same mechanism of inhibiting the synthesis of the bacterial cell walls.
Both are available as generic drugs, and both treat bacterial infections.
However, amoxicillin is newer and acts against a wider range of bacteria compared to penicillin.
Moreover, amoxicillin was chemically modified by adding an amino group to the original structure to increase potency and overcome antimicrobial resistance.
The available Active Pharmaceutical Ingredient (API) forms of amoxicillin include anhydrous, trihydrate, and sodium salt.
Amoxicillin trihydrate powder
Amoxicillin trihydrate is the most stable hydrated form of amoxicillin and with greater oral bioavailability.
Amoxicillin trihydrate is crystalline, off-white, has a different molecular weight (419.5 g/mol), a different molecular formula (C16H25N3O8S), a different CAS number (61336-70-7).
Amoxicillin trihydrate is slightly soluble in water.
Amoxicillin Sodium
It is the sodium salt form of amoxicillin, and it is available as a powder for injection or infusion.
Amoxicillin Injection is commonly used in severe infections when the oral route of administration isn't available or applicable.
Amoxicillin tablets 500 mg
Amoxicillin oral tablets are available as immediate-release (IR) and chewable tablets, which both are available as generic drugs with doses of 500 mg and 875 mg.
It also includes an extended-release (ER) formulation, which is available as the brand-name drug Moxatag® with a dose of 775 mg.
The extended-release formulation should not be crushed or chewed; besides, the treatment must be taken within an hour.
Every 5ml of oral suspension contains 125 mg amoxicillin (as amoxicillin trihydrate).
Amoxicillin Suspension is indicated to treat various bacterial infections in adults and children, including acute sinusitis, acute otitis media, and acute cystitis.
Amoxicillin suspension must be shaken well before measuring the dose, and the provided dosing syringe should be used.
The measured dose of suspension may be mixed with water, baby formula, or fruit juice and must be administered immediately after mixing.
The standard dose for adults and children more than 40 kg is 250 mg every 8 hours, and this dose could be increased in severe infections.
The standard dose of children less than 40 kg is 125 mg every 8 hours, and this dose could be increased in severe infections.
Amoxicillin and clavulanate potassium
Amoxicillin/clavulanate potassium (Augmentin®) is a combination of amoxicillin and the beta-lactamase inhibitor, clavulanate potassium (the potassium salt of clavulanic acid).
Amoxicillin and clavulanate potassium are used to treat various bacterial infections such as pneumonia, bronchitis, and skin infections.
Amoxicillin and clavulanate potassium should not be used in patients with renal function disorders. Moreover, they should be used with caution during breastfeeding and pregnancy.
Sodium benzoate is usually used as a preservative in the amoxicillin suspension formulation; therefore, the drug should be used with caution in children allergic to sodium benzoate to avoid the risk of jaundice.
5.Manufacturing process of Amoxicillin
The first step of manufacturing is milling the API (e.g., amoxicillin trihydrate powder) then sieving the milled powder for size uniformity.
After sieving, the powder is mixed with other active ingredients (such as magnesium stearate, sodium benzoate, and colloidal anhydrous silica) and then blended till homogeneity.
Roller compaction is processed on the homogenous blend to get granules.
The granules are then compressed in a tablet press followed by film coating to produce the final product.
6.Uses of Amoxicillin
Amoxicillin for urinary tract infection
Amoxicillin antibiotics stop the growth of bacteria in urine, including E. coli, P. mirabilis, and E. faecalis.
The antibiotic is taken twice daily or every 8 hours with or without food.
Amoxicillin for ear, nose, and throat infections
It is indicated for treating infections caused by Streptococcus spp., S. pneumonia, Staphylococcus spp., and H. influenza.
Amoxicillin for sinus infection
Since it is effective against most strains of bacteria, amoxicillin is used in the treatment of acute sinusitis caused by bacterial infection.
Amoxicillin/clavulanate potassium is the first-line antibiotic for sinus bacterial infections.
8.Dosage of Amoxicillin
Amoxicillin capsules, tablets, and oral suspension are usually taken every 12 hours (twice daily) or every 8 hours (three times a day) with or without food and at around the exact time every day according to the physician's prescription and directions.
Children weighing 40 kg or more should be dosed according to the adult recommendations
Amoxicillin is available in the following strengths:
Tablet: 500 mg, 875 mg
Chewable tablets: 125 mg, 250 mg
Capsules: 250 mg, 500 mg
Powder for oral suspension: 50 mg/mL, 125 mg/5mL, 200 mg/5mL, 250 mg/5mL, 400 mg/5mL
For bacterial infections:
The standard dose for adult and children weighing 40 kg or more
250 to 500 mg every 8 hours, or 500 to 875 mg every 12 hours.
The standard dose for children less than 40 kg and infants less than 3 months of age.
Based on the weight, the dose is 20-40 mg kg day in divided doses and taken every 8 hours or 25-45 mg kg day in divided doses and taken every 12 hours.
The standard dose infants less than 3 months of age.
30 mg kg day in divided doses and taken twice daily.
For of H. pylori infection:
Dual Therapy: 1 g of amoxicillin and in combination with 30 mg lansoprazole orally every 8 hours.
Triple Therapy: 1 g of amoxicillin and in combination with 500 mg of protein synthesis inhibitor, clarithromycin, and 30 mg lansoprazole, orally every twice daily.
The duration of treatment differs according to the severity of the infection and the patient's medical status.
The treatment should not be stopped even after feeling better because the infection may still exist.
Renal functions may require some adjustments and cautions, especially in patients with renal function problems, as the main excretion route of amoxicillin in most people is by the kidney.
9.Side effects of Amoxicillin
The most common side effects of amoxicillin are skin rash and gastrointestinal symptoms, including nausea, vomiting, and diarrhea, which usually disappear within few days.
However, amoxicillin may result in serious complications which require immediate help; these effects include hypersensitivity reactions to amoxicillin (anaphylaxis).
10. Price of Amoxicillin API powder
The average price of amoxicillin API powder is $24 (USD/kg).
11. Manufacturers of Amoxicillin trihydrate API in china
PharmaSources
PharmaSources is a vertical e-commerce online marketplace that serves the pharmaceutical industry. We provide information on high-quality online shopping medical products and suppliers for global customers and deliver services to over 90,000 active members across 211 countries. We are featuring more than 1,600,000 products in more than 30 categories spanning the entire pharma supply chain!
Shaoxing Hantai Pharmaceutical Co., Ltd.
Sinopharm Weiqida Pharmaceutical Co., Ltd.
South China Pharmaceutical Co., Ltd.
South China Pharmaceutical Co., Ltd.
Nanjing Dorra Pharmaceutical Technology Co., Ltd.
Nanjing Kingway Pharmaceutical Co., Ltd
Tianjin Sinomed Pharmaceutical Co., Ltd.
12.FAQ
Is amoxicillin a safe antibiotic?
Amoxicillin is considered a low-risk drug and safe to take in children, pregnant (category B drug by FDA), and breastfeeding women.
However, amoxicillin can be unsuitable for some individuals and may cause serious side effects, so the doctor must be informed if the patient:
Had previous allergic reactions to amoxicillin or any antibiotic in the same class.
Complaining from stomach cramping and severe diarrhea that lasts for at least two days.
Has problems in the liver and renal functions.
Had or planning to have a vaccination.
How long does it take for amoxicillin to start working?
According to the drug's data, amoxicillin starts working after reaching peak concentration in the blood, which takes about 1-2 hours after oral administration.
It takes about 3 days for the symptoms to improve; however, the improvement could be seen within a day in some cases.
If no improvement were seen after 3 days, medical consultation is required for other treatment options.
What kind of bacteria does amoxicillin kill?
Amoxicillin acts against wider varieties of gram-positive bacteria than penicillin, including most Staphylococcus species and Enterococcus faecalis.
Also, amoxicillin acts against gram-negative bacterial species, including Haemophilus influenza, some Escherichia coli, Neisseria gonorrhea, and Proteus mirabilis.
References
https://pubchem.ncbi.nlm.nih.gov/compound/Amoxicillin
https://go.drugbank.com/drugs/DB01060
https://www.ncbi.nlm.nih.gov/books/NBK482250/
https://www.healthline.com/health/amoxicillin-shelf-life
https://pubchem.ncbi.nlm.nih.gov/compound/Amoxicillin-trihydrate#section=Component-Compounds
https://www.usp-pqm.org/sites/default/files/pqms/article/amoxicillin-pir-jul2018.pdf
https://www.drugs.com/amoxicillin_clavulanate.html
https://www.mayoclinic.org/drugs-supplements/amoxicillin-oral-route/proper-use/drg-20075356
https://pubmed.ncbi.nlm.nih.gov/22873492/
https://www.pharmacompass.com/price/amoxicillin-trihydrate
https://www.healthline.com/health/pregnancy/amoxicillin-safety#side-effects
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