Test Method for Amoxicillin Capsule

Amoxicillin is used to treat a wide variety of bacterial infections. This medication is a penicillin-type antibiotic. It works by stopping the growth of bacteria. This antibiotic treats only bacterial infections. It will not work for viral infections (such as the common cold, or flu). Amoxicillin is also used with other medications to treat stomach/intestinal ulcers caused by the bacteria H. pylori and to prevent the ulcers from returning.

Each Capsule Contains:
Amoxicillin Trihydrate BP equivalent to Amoxicillin . . . . 250 mg

Visually examine the representative number of capsules for color, shape, markings & the presence of foreign matter.

Shake 600 mg of capsule powder with 5 mL of water for 5 minutes, filter, wash the residue first with absolute ethanol and then with ether, and dry at a pressure not exceeding 0.7 kPa for 1 hour. Triturate 1-2 mg of residue with 300 - 400mg of finely powdered and dried potassium bromide. Carefully grind the mixture, spread it uniformly in a suitable die, and submit it to pressure to form a transparent disc. Carefully place the disc in the disc holder & placed in an IR spectrophotometer. Record the absorption spectrum.

Average fill weight
Weigh the content of 20 capsules & find out the average fill weight.

Uniformity of Fill Weight
  • Select 20 capsules at random from the sampled lot.
  • Determine the weight of one of the twenty capsules. Open it and empty the contents as completely as possible into a tarred vessel; weigh and record the net content.
  • Repeat the above step for the remaining 19 capsules.
  • Calculate the Uniformity of Fill Weight using the following formula.

Place 1 capsule in each of the 6 tubes of the basket & cover with disc. Operate the apparatus using water, maintained at 37 ± 2°C, as the immersion fluid. At the end of the specified time, lift the basket from the fluid & observe the dosage units. All of the dosage unit disintegrate completely.
Note: Disintegration is considered to be complete when no residue except fragments of the capsule shell remains on the screen of the test apparatus.

Medium Water ; 900 mL
Apparatus I ( Basket )
Speed 100 RPM
Time 45 minutes.
Temperature 37°C ± 0.5°C

Place 900 mL of dissolution medium maintained at 37 ± 0.5°C in 6 dissolution vessels separately & fix in the dissolution bath. Place 1 capsule into each of six basket & fix the basket to the shaft, bring it into the position. Operate the instrument at 100 RPM for 45 min. At the end of 45 min, withdraw 10mL of sample of the medium & filter through 0.45µ filter.
Measure the absorbance at 272nm.

Standard Solution:
Weigh 31.8mg of Amoxicillin Trihydrate SRS 100mL volumetric flasks, add 70mL of water to dissolve & dilute with same to volume. Filter through 0.45µ filter.
Measure the absorbance at 272nm.

Calculate the percentage of labeled amount dissolved:

Chromatographic Conditions:
Column 250 × 4.6 mm, 5 µm, C18
Flow Rate 1.0 mL/minute
Column Temperature 25°C
Detection Wavelength 254 nm
Injection Volume 50 µL

Preparation of 0.2 M potassium dihydrogen phosphate:
Dilute 6.81 g potassium dihydrogen phosphate in 250 mL with water.

Preparation of Buffer:
250 mL of 0.2 M potassium dihydrogen phosphate solution, adjust pH 5.0 with dilute sodium hydroxide solution and dilute to 1000 mL with water.

Preparation of Mobile phase:
Mix 200 mL of acetonitrile and 800 mL of buffer. Degas and filter the mixture.

Standard Preparation:
Transfer about 70 mg of Amoxicillin trihydrate working standard in 100mL volumetric flask, add 80mL of mobile phase, sonicate to dissolve and make up to the mark with mobile phase. Transfer 5 mL of this solution to 50 mL mobile phase.

Sample Preparation:
Transfer about 73.1 mg of capsule powder in 100mL volumetric flask, add 80mL of mobile phase, sonicate to dissolve and make up to the mark with mobile phase. Transfer 5 mL of this solution to 50 mL mobile phase.

The test is not valid unless the RSD for replicate injections is NMT2.0%


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