Assay of Ibuprofen Tablets

Ibuprofen and NSAIDs

• Ibuprofen is a non-steroidal anti-inflammatory agent (NSAID), also known as Isobutylphenylpropionic acid.
• Other examples of NSAIDs include Aspirin, Naprosyn, Diclofenac, and Celecoxib.

Assay of Ibuprofen Tablets

• The assay involves three steps: Uniformity of weight test, Standardization of 0.1 M NaOH, and Assay of Ibuprofen tablets.

Uniformity of Weight Test

• Determine the weight of the tablet/powder that contains a specific mass of the API (Ibuprofen).
• Steps involved:
  • Weigh 20 tablets together and determine the average weight.
  • Weigh 20 tablets individually.
  • Calculate the deviation of the individual weight from the average weight.

Standardization of 0.1 M NaOH Solution

• Involves three steps:
  • Standardization of 0.1 M HCl.
  • Standardization of 0.05 M H2SO4.
  • Using Sulphamic acid (H3NSO3).

Assay of Ibuprofen using 0.1 M NaOH Solution

• Transfer a quantity of the powder containing 0.450 g of ibuprofen to a sintered-glass crucible.
• Extract with five 10 mL quantities of methanol R.
• Add 0.4 mL of phenolphthalein solution R1.
• Titrate with 0.1 M sodium hydroxide until a red color is obtained.
• Perform a blank titration.

Determination of % Content

• Assuming the sample was obtained from a tablet.
• An equivalent weight would have been taken (y g).
• Weight obtained from assay is x g.
• % content is calculated using these values.

Considerations for Titrations

• Three burette readings are required and must not be more than 0.05 mL apart from each other for both standardization and assay of sulphanilamide.
• Precautions:
  • Appropriate burette reading.
  • Good pipetting and solution transfer skills.
  • Avoid spilling of reagents.
  • Ensure proper mixing of all solutions.