Packaging and storage—
Preserve in tight containers.
Labeling—
Label Boluses to indicate that they are for veterinary use only.
Identification—
A:
Crush 1Bolus,boil a portion of the powder,equivalent to about 300mg of aspirin,with 50mLof water,cool,and add a drop of ferric chloride TS:a violet-red color is produced.
B:
The retention time of the aspirin peak in the chromatogram of the Assay preparationcorresponds to that in the chromatogram of the Standard preparation,as obtained in the Assay.
Dissolution á711ñ—
Medium:
0.05Macetate buffer,prepared by mixing 8.97g of sodium acetate trihydrate with 2700mLof water,adjusting with glacial acetic acid to a pHof 4.50±0.05,and diluting with water to 3000mL,and mixing;500mL.
Apparatus 1
[NOTE—Use basket and shaft dimensions that accommodate the size of the individual bolus.]:100rpm.
Time:
45minutes.
Diluting solution—
Prepare a mixture of acetonitrile and formic acid (99:1).
Procedure—
Determine the amount of aspirin (C
9H
8O
4)dissolved from UVabsorbances at the wavelength of the isosbestic point of aspirin and salicylic acid at 265±2nm of filtered portions of the solution under test,suitably diluted with
Diluting solution,if necessary,in comparison with a Standard solution having a known concentration of
USP Aspirin RSin the same medium.
[NOTE—Prepare the Standard solution at the time of use.
]
Tolerances—
Not less than 80%(Q)of the labeled amount of C9H8O4is dissolved in 45minutes.
Limit of salicylic acid—
Using the chromatograms of the
Standard preparationand the
Assay preparation,obtained as directed in the
Assay,calculate the percentage of salicylic acid (C
7H
6O
3)in the portion of Boluses taken by the formula:
100,000(C/WA)(rU/rS),
in which
Cis the concentration,in mg per mL,of
USP Salicylic Acid RSin the
Standard preparation;WAis the quantity,in mg,of aspirin (C
9H
8O
4)in the portion of Boluses taken,as determined in the
Assay;and
rUand
rSare the salicylic acid peak responses obtained from the
Assay preparationand the
Standard preparation,respectively:not more than 0.3%is found.
Assay—
Mobile phase—
Dissolve 2g of sodium 1-heptanesulfonate in a mixture of 850mLof water and 150mLof acetonitrile,and adjust with glacial acetic acid to a pHof 3.4.Make any necessary adjustments (see
System Suitabilityunder
Chromatography á621ñ).
Diluting solution—
Prepare a mixture of acetonitrile and formic acid (99:1).
Assay preparation—
Weigh and finely powder not fewer than 10Boluses.Transfer an accurately weighed portion of the powder,equivalent to about 400mg of aspirin,to a 100-mLvolumetric flask,dilute with Diluting solutionto volume,and stir by mechanical means for about 15minutes.Pass a portion of this solution through a filter having a 0.5-µm or finer porosity,and use the filtrate as the Assay preparation.
Chromatographic system
(see
Chromatography á621ñ)—The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm ×25-cm column that contains 5-µm packing L1.The flow rate is about 1mLper minute.Chromatograph the
Standard preparation,and record the peak responses as directed for
Procedure:the relative retention times are about 0.6for salicylic acid and 1.0for aspirin,and the relative standard deviation of the aspirin peak response for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 20µL)of the
Standard preparationand the
Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of aspirin (C
9H
8O
4)in the portion of Boluses taken by the formula:
1000C(rU/rS),
in which
Cis the concentration,in mg per mL,of
USP Aspirin RSin the
Standard preparation;and
rUand
rSare the aspirin peak responses obtained from the
Assay preparationand the
Standard preparation,respectively.