»Xylazine Hydrochloride contains not less than 98.0percent and not more than 102.0percent of C12H16N2S·HCl.
Packaging and storage
Preserve in tight containers.Store at 25
,excursions permitted between 15
Where it is intended for veterinary use only,the label so states.
USP Reference standards á11ñ
USP Xylazine Hydrochloride RS
A:Infrared Absorption á197Kñ.
B:Thin-Layer Chromatographic Identification Test á201ñ
5mg per mL,in methanol.
Developing solvent system:
methanol and ammonium hydroxide (98.5:1.5).
Separately apply 1µLof the Test solution
and the Standard solution.
Allow the applications to dry with the aid of a stream of nitrogen,develop in a saturated chromatographic chamber,and dry the plate in a current of air:the size,intensity,and RF
value of the principal spot obtained from the Test solution
correspond to those of the principal spot obtained from the Standard solution.
Melting range á741ñ:
between 4.0and 6.0,in a solution (1in 100).
Loss on drying á731ñ
Dry it at 105
for 4hours:it loses not more than 1.0%of its weight.
Residue on ignition á281ñ:
not more than 0.1%.
Heavy metals,Method IIá231ñ:
20µg per g.
Examine the chromatogram obtained from the Assay preparation.
Calculate the percentage of impurities in the Xylazine Hydrochloride taken by the formula:
in which rs
is the sum of the areas of all the impurity peaks observed;and rU
is the area of the xylazine peak:the sum of the impurity responses is not greater than 2.0%.
Dissolve 6.0g of sodium 1-heptanesulfonate in 2500mLof water,add 60mLof glacial acetic acid,dilute with water to 3000mL,and mix.Prepare a mixture of 2200mLof this solution and 1800mLof methanol,and pass through a filter having a 0.5-µm or finer porosity.Make adjustments if necessary (see System Suitability
under Chromatography á621ñ
Prepare a solution of USP Xylazine Hydrochloride RS
in Mobile phase
having a known concentration of about 1mg per mL.
Transfer about 25mg of Xylazine Hydrochloride,accurately weighed,to a 25-mLvolumetric flask,dissolve in and dilute with Mobile phase
to volume,and mix.
Chromatographic system(see Chromatography á621ñ)
The liquid chromatograph is equipped with a 254-nm detector,a 2-mm ×2-cm guard column that contains packing L1,and a 3.9-mm ×30-cm analytical column that contains packing L1and is maintained at a constant temperature of about 40
.The flow rate is about 2.5mLper minute.Chromatograph the Standard preparation,
and record the peak responses as directed for Procedure:
the relative standard deviation for replicate injections is not more than 2.0%.[NOTE
After daily use,rinse the column with 100mLof acetonitrile and with 100mLof methanol,and store the column containing methanol.]
Separately inject equal volumes (about 20µL)of the Standard preparation
and the Assay preparation
into the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of C12
S.HCl in the portion of Xylazine Hydrochloride taken by the formula:
in which C
is the concentration,in mg per mL,of USP Xylazine Hydrochloride RS
in the Standard preparation;
are the areas of the xylazine peak responses in the chromatograms obtained from the Assay preparation
and the Standard preparation,
:Ian DeVeau,Ph.D.,Senior Scientist
:Volume No.29(6)Page 2005