Determined by liquid chromatography.
Test solution: Weigh and powder 20 tablets. Disperse a quantity of the powder containing 25mg of olpatadine HCl with 60ml of mobile phase, ultrasound for 10 minutes, and dilute to 100.0ml with the mobile phase. Centrifuge at about 2500rpm for 10 minutes and dilute 5ml of this solution to 25ml with mobile phase.
Reference solution: Dissolve 25mg of olpatadine HCl reference standard in 15ml of mobile phase and dilute to 50.0ml with mobile phase. Dilute 5.0ml of this solution to 50.0ml with the mobile phase.
Chromatographic system:
- A stainless steel column 25cmX4.6 mm, packed with octadecylsilane bonded to porous silica (5µm)
- Mobile phase: a mixture of 72 volumes of a buffer solution prepared by dissolving 6.8gm of potassium dihydrogen orthophosphate in 1000ml of water, adjusted to pH 4.5 with O.P.A. or triethylamine and 28 volumes of acetonitrile.
- Flow rate: 1ml per minute,
- Spectrophotometer set at 210nm,
- Injection volume: 20µl
Inject the reference solution. The test is not valid unless the column efficiency is not less than 4000 theoretical plates, the tailing factor is not more than 2.0 and the relative standard deviation for replicate injections is not more than 2.0 per cent.
Inject the reference solution and test solution.
Calculate the content of Olpatadine HCl in tablet.
Formula for calculation:
Area of Test STD wt. 5 100 25 Potency
—————-–X———–X————X—————-–X————-X—————XAverage weight
Area of STD 50 25 Weight of test 5 100
Acceptance criteria: 90.0%-110.0%
