Amoxicillin Hydrate


is a semisynthetic aminopenicillin antibiotic with bactericidal activity. It is used as Amixicillin Hydrate Amoxicillin binds to and inactivates penicillin-binding protein (PBP) 1A located on the inner membrane of the bacterial cell wall.


IUPAC name of Amoxicillin Hydrate is

(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 

Molecular Formula

C16H19N3O5S • 3H2O

Chemical Structure

Amoxicillin Hydrate

Formula Weight




Physical Appearance:

Amoxicillin Hydrate occurs as white to light yellowish white, crystals or crystalline powder.


It is slightly soluble in water and in methanol, and very slightly soluble in ethanol (96%).


Determine the infrared absorption spectrum of Amoxicillin Hydrate as directed in the potassium bromide disk method under Infrared Spectrophotometry , and compare the spectrum with the Reference Spectrum or the spectrum of Amoxicillin RS: both spectra exhibit similar intensities of absorption at the same wave numbers.

Optical rotation

+290°   to   +315°

(0.1 g calculated on the anhydrous basis, water, 100 mL, 100 mm).

Heavy metals

To 1.0 g of Amoxicillin Hydrate add 2 mL of a solution of magnesium sulfate heptahydrate (1 in 4), mix, and heat on a water bath to dryness. Carbonize the residue by gently heating. After cooling, add 1 mL of sulfuric acid, heat carefully, then heat at 500°C – 600°C to incinerate. After cooling, add 1 mL of hydrochloric acid to the residue, and heat on a water bath to dryness. Then add 10 mL of water to the residue, and heat on a water bath to dissolve. After cooling, add ammonia TS to adjust the pH to 3 – 4, and add 2 mL of dilute acetic acid. If necessary, filter, wash the residue on the filter with 10 mL of water, transfer the filtrate and washings into a Nessler tube, add water to make 50 mL, and use this solution as the test solution. Prepare the control solution as follows:

To 2.0 mL of Standard Lead Solution add 2 mL of a solution of magnesium sulfate heptahydrate (1 in 4), then proceed in the same manner as for preparation of the test solution (not more than 20 ppm).


Not less than 11.0% and not more than 15.0%

(0.1 g, volumetric titration, direct titration).


Weigh accurately an amount of Amoxicillin Hydrate and Amoxicillin RS, equivalent to about 30 mg (potency), dissolve each in a solution of boric acid (1 in 200) to make exactly 100 mL, and use these solutions as the sample solution and standard solution. Perform the test with exactly

10 mL each of the sample solution and standard solution as directed under Liquid Chromatography according to the following conditions, and calculate the peak areas, AT and AS, of amoxicillin in each solution.

Amount [µg (potency)] of amoxicillin (C16H19N3O5S)


= MS × AT/AS × 1000

MS = Amount [mg (potency)] of Amoxicillin RS taken

Operating conditions:


An ultraviolet absorption photometer (wavelength: 230 nm).


A stainless steel column 4.6 mm in inside diameter and 15 cm in length, packed with octadecylsilanized silica gel for liquid chromatography (5 µm in particle diameter).

Column temperature:

A constant temperature of about 25°C.

Mobile phase:

Dissolve 1.361 g of sodium acetate trihydrate in 750 mL of water, adjust to pH 4.5 with   acetic acid, and add water to make 1000 mL. To 950 mL of this solution add 50 mL of methanol.

Flow rate:

Adjust so that the retention time of amoxicillin is about 8 minutes.

System performance:

When the procedure is run with 10 µL of the standard solution under the above operating conditions, the number of theoretical plates of the peak of amoxicillin is not less than 2500.

System repeatability:

When the test is repeated 6 times with 10 µL of the standard solution under the above operating conditions, the relative standard deviation of the peak area of amoxicillin is not more than 1.0%.

Containers and storage Containers:

Tight containers at Room temperature


≥ 2 years

Note before using Amoxicillin Product:

Do not use this medication if you are allergic to amoxicillin or to any other penicillin antibiotic, such as ampicillin, dicloxacillin, oxacillin, penicillin, and others.

Before using amoxicillin, tell your doctor if you are allergic to cephalosporins such as Omnicef, Cefzil, Ceftin, Keflex, and others. Also tell your doctor if you have asthma, liver or kidney disease, a bleeding or blood clotting disorder, mononucleosis (also called “mono”), or any type of allergy.

Amoxicillin can make birth control pills less effective. Ask your doctor about using a non-hormone method of birth control (such as a condom, diaphragm, spermicide) to prevent pregnancy while taking this medicine. Take this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Amoxicillin will not treat a viral infection such as the common cold or flu. Do not share this medication with another person, even if they have the same symptoms you have.

Antibiotic medicines can cause diarrhea. This may happen while you are taking amoxicillin, or within a few months after you stop taking it. This may be a sign of a new  infection. If you have diarrhea that is watery or bloody, stop taking this medicine and call your doctor. Do not use anti-diarrhea medicine unless your doctor tells you to.

Related Posts:

  1.    EDTA          2.  Diclofenac Sodium            3.   Vitamin “C”
%d bloggers like this: