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Haematex Ellagic Acid is for use in activating intrinsic blood clotting factors in activated partial thromboplastin time (APTT) and other clotting tests. Also for use in powdered APTT reagents and point of care (POC) devices. Ellagic Acid is a yellowish powder containing 10% ellagic acid-zinc complex in a carbohydrate base buffered with HEPES (4-(2-hydroxyethyl)-1-piperazine ethanesulfonic acid).
Gradually dispersible in water or 0.02M HEPES buffer at 10% or lower concentrations to form a contact activator solution.
Approximate pH of a 1% solution is 7.7.
A 1% solution of a typical 10% EA powder was serially diluted in 0.02M Na/H.HEPES pH 7.4 buffer to achieve the following results in APTT tests on pooled normal plasma supplemented with 0.002% synthetic phospholipid (PL = DOPE:DOPS:DOPC = 5:3:2).
| Activator | Final Conc’n (%) | 3′ APTT(sec) |
|---|---|---|
| EA.030314 (1% x 10%) 1/2 |
0.05 | 31.4 |
| 1/4 dilution | 0.025 | 27.6 |
| 1/8 dilution | 0.0125 | 27.9 |
| 1/16 dilution | 0.0063 | 26.7 |
| Blank diluent | 0 | 103 |
The 10% EA powder has strong contact activator activity even at concentrations below 0.01%.
EA has best stability in low ionic strength solutions (i.e. minimize NaCl or other salts in solution).
Ensure that the pH of any ellagic acid solutions prepared from this powder remains above 7.5, otherwise free ellagic acid may precipitate out over time. (This EA precipitation would be apparent from development of turbidity and accompanied by loss of contact activity. A small addition of tris base to pH 7.6-7.8 is recommended). This EA powder is reasonably stable if kept dry at room temperature or 4°C. Storage at below -25°C is suggested for longest shelf life (2 years).