Determined by liquid chromatography.
Test solution: Weigh and powder 20 tablets. Disperse a quantity of the powder containing 160mg of fenofibrate with 60ml of methanol, sonicate for 15 minutes, dilute to 250.0ml with the same solvent centrifuge at 2500 rpm for about 10 minutes, and filter. Dilute 10ml of the filtrate to 25ml with the mobile phase.
Reference solution (a): A 0.18 per cent w/v solution of atorvasatatin calcium reference standard in methanol. Dilute 5ml of this solution to 50 ml with methanol.
Reference solution (b): A 0.064 per cent w/v solution of fenofibrate reference standard in methanol.
Reference solution (c): Dilute 5ml reference solution (a) and 10.0ml of reference solution (b) to 25 ml with mobile phase.
Chromatographic system:
- A stainless steel column 25cmX4.6mm packed with octadecylsilane bonded to porous silica (5µm), (such as hypersil BDS C18)
- Mobile phase: a mixture of 35 volumes of a buffer solution prepared by dissolving 6.8g of potassium dihydrogen orthophosphate in 1000ml of water, adjusted to pH 2.5 with O.P.A., 35 volumes of acetonitrile and 30 volumes of methanol.
- Flow rate: 1.5ml per minute,
- Spectrophotometer set at 280nm,
- Injection volume: 20µl
Inject reference solution(c). The test is not valid unless the resolution between atorvastatin and fenofibrate peaks is not less than 27, the column efficiency is not less than 7000 theoretical plates, the tailing factor is not more than 2.0 and the relative standard deviation of replicate injections is not more than 2.0 per cent for atorvastatin peak.
Inject the reference solution (c) and test solution.
Calculate the content of Atorvastatin and fenofibrate in tablets.
Acceptance criteria: 90.0%-110.0%
