Test Method for Paracetamol and Diclofenac Sodium Tablets

Paracetamol and Diclofenac Sodium Tablets is a pain relieving medicine. It is used to reduce pain and inflammation in conditions like rheumatoid arthritis, ankylosing spondylitis, and osteoarthritis. It may also be used to relieve muscle pain, back pain, toothache, or pain in the ear and throat.

Each Tablet Contains
Paracetamol BP . . . . . . . . . . .500 mg

Diclofenac Sodium BP . . . . . 50mg

Description:

Visually examine the representative number of tablets for colour, shape, markings and the presence of foreign matter

Identification:

The retention time of the major peaks in the chromatogram of sample preparation should corresponds to that of the major peaks in the chromatogram of the standard preparation, as obtained in the assay.

Average Weight:

Weigh 20 tablets & calculate the average weight using calibrated weighing balance.

Weight Variation:

Weigh 20 tablets individually & find out the average weight.

Formula:

Thickness:

Determine the thickness of 10 tablets individually using Vernier caliper.

Hardness:

Determine the hardness of 10 tablets individually using hardness tester.

Friability:

Weigh tablets weight equivalent to 6.5 g & put the tablets in the friability test apparatus & operate the instrument for 4 minutes. (4×25 revolutions = 100 revolutions). Reweigh the tablets after the test.

Formula:

Initial weight of tablets : ________ W1 g

Final weight of tablets : _________ W2 g

Loss of weight : ______________ (W1 – W2) g

Disintegration:

Place 1 tablet in each of the 6 tubes of the basket & cover with the 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 units disintegrate completely.

Note: Disintegration is considered to be completed when no residues except fragments of the undissolved tablet remain on the screen of the test apparatus.

Dissolution:

Dissolution Condition:

Medium : Phosphate Buffer pH 6.8 ; 900 mL.

Apparatus : II ( Paddles )

Speed : 50 RPM

Time : 45 minutes.

Temperature : 37°C ± 0.5°C

Preparation of Buffer 6.8:

Mix 40.8 gm of Potassium dihydrogen orthophosphate and 6.545 gm of sodium hydroxide in 6L Water. Adjust pH 6.8 with NaOH or Orthophosphoric acid.

Standard solution I:

Transfer about 50 mg of Diclofenac sodium working standard into a 50 ml volumetric flask and add 20ml of the Acetonitrile, sonicate to dissolve dilute up to the mark with dissolution media.

Standard solution II:

Transfer about 50 mg of Paracetamol working standard into a 100 ml volumetric flask and add 30ml of the dissolution media, sonicate to dissolve, add 5 ml of Standard-I and dilute up to the mark with dissolution media.

Sample Preparation:

Place 900 mL of dissolution medium maintained at 37 ± 0.5°C in 6 dissolution vessels separately & fix in the tablet dissolution bath. fix the paddle to the shaft & bring it into the position. Place 1 tablet each into 6 dissolution vessels. Operate the instrument at 50 RPM for 45 min. At the end of 45 min, withdraw 10mL of sample and, Filter through 0.45µ filter and fill the vial.

Chromatography Condition:

Refer Assay method 2.10

System suitability:

The% RSD for five replicate injection of standard preparation should NMT 2.0 % Procedure:

Inject standard preparation in five replicate and record the chromatogram . It should comply with the system suitability criteria as mentioned above. Inject sample preparation for each tablet and record the chromatogram, calculate the percent of dissolution by using the following formula:

Calculation:

Calculate the percentage of labeled amount dissolved:

Where,

At = Area of Sample Solution
As = Average Area of standard solution
Ws = Weight of standard
V = Volume of Medium
L = Label Claim
P = Potency of Standard

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Assay:
Chromatographic Conditions:
Column : 250 mm × 4.6 mm, C18, 5 µm
Flow Rate : 1.0 mL/minute
Column Temperature : 40°C
Detection Wavelength : 300 nm
Injection Volume : 10 µL
Mobile Phase: Buffer : Acetonitrile (40 : 60, v/v)

Buffer Preparation:

Add 1ml of phosphoric acid in to 1000ml of water and adjust pH 3.5 ± 0.05 with trimethylamine.

Preparation of standard- I:

Transfer about 50 mg of Diclofenac Sodium SRS into a 50 ml volumetric flask and add 35ml of Mobile Phase, sonicate to dissolve dilute up to the mark with Mobile Phase.

Preparation of standard- II:

Transfer about 50 mg of Paracetamol SRS into a 25 ml volumetric flask and add 10ml of Mobile Phase, sonicate to dissolve, add 5ml of standard - I and dilute up to the mark with Mobile Phase.

Sample Preparation:

Weigh & Powder 20 tablets. Transfer tablet powder (equivalent to 200 mg of Paracetamol) into a 100 ml volumetric flask, add 70ml of Mobile Phase, sonicate for 30 minutes , dilute up to the mark with Mobile Phase. Filter the final solution through 0.45µm PVDF syringe filter and use the filtrate, discarding the first 5ml of the filtrate.

System suitability:

The % RSD for five replicate injection of standard preparation should NMT 2.0 %

Procedure:

Inject standard preparation in five replicate and record the chromatogram. It should comply with the system suitability criteria as mention above. Inject sample preparation in duplicate, record the chromatogram and calculate the percent of assay by using the following formula:

Calculation:

Where,

At = Average Area of Sample solution
As = Average Area of Standard solution
Ws = Weight of Standard
Wt = Weight of Sample
ATW = Average tablet weight
P = Potency of Standard
L = Label Claim