Determined by High performance liquid chromatography:
Standard solution: Weigh accurately about 162.5 mg of Paracetamol reference standard, and 50 mg of Aceclofenac reference standard in 100ml volumetric flask, dissolve in and dilute to the mark with mobile phase. Shake well and further dilute 2 ml to 25 ml with mobile phase. Shake well and filter through 0.45µm nylon filter.
Test Solution: Weigh accurately about equivalent to 162.5 mg of Paracetamol from crushed powder of 20 tablets in 100 ml volumetric flask, add 50 ml of mobile phase, sonicate for 5 minutes, cool to room temperature and dilute to the mark with mobile phase, filter. Shake well and further dilute 2 ml to 25 ml with mobile phase, shake well and filter through 0.45µm nylon filter.
Procedure: Inject separately standard and test preparation. Inject five replicate injection of working standard and two replicate injection of test preparation.RSD of replicate injection should not more than 2%. Calculate the assay of Paracetamol and Aceclofenac by comparison to peak area of standard preparation.
Chromatographic system:
- A stainless steel column (25cm X4.6mm,) C18
- Mobile phase: Methanol :Water and G.A.A. (80: 20) and (0.01ml); degas
- Flow rate: 1.2ml per minute,
- Spectrophotometer set at 280nm,
- Injection volume: 20µl
Inject the reference solution and test solution.
Calculate the content of Aceclofenac and Paracetamol in tablets.
Formula:
Area of Test STD Wt.(mg) 2 100 25 Potency
—————–X————–X———-X—————–X———–X————–X Average weight
Area of STD 100 25 Test Wt. (mg) 2 100
