Determined by liquid chromatography.
Test solution: Weigh and powder 20 tablets. Weigh a quantity of powder containing about 25mg ramipril, disperse in water and dilute to 250.0ml with the mobile phase, filter. Dilute 3.0ml of this solution to 25.0ml with the mobile phase and mix.
Reference solution (a): A 0.024 per cent w/v solution of ramipril reference standard in the mobile phase.
Reference solution (b): A 0.06 per cent w/v solution of hydrochlorothiazide reference standard in the mobile phase.
Reference solution (c): Dilute reference solution (a) and (b) with the mobile phase to obtain a solution having a known concentration similar to the test solution.
Chromatographic system:
- A stainless steel column 25cm X4.6mm, packed with octadecylsilane bonded to porous silica (5µm) (such as thermo quest hypersil),
- Mobile Phase: a mixture of 55 volumes of water, 45 volumes of acetonitrile and 0.1 volume of triethylamine, adjusted to pH 3.0 with O.P.A.
- Flow rate: 1ml per minute,
- Spectrophotometer set at 210nm,
- Injection volume: 20µl
Inject reference solution (c). The test is not valid unless the relative standard deviation for replicate injections for each peak is not more than 2.0 percent.
Inject reference solution (c) and the test solution.
Calculate the content of Ramipril and Hydrochlorothiazide in the tablet.
Acceptance criteria: 90.0%-110.0%
