-carboxylic acid,methyl ester,hydrochloride
»Yohimbine Hydrochloride contains not less than 98.0percent and not more than 102.0percent of C21H26N2O3·HCl,calculated on the dried basis.
Packaging and storage
Preserve in tight containers,and store at controlled room temperature.
Where it is intended for veterinary use only,it is so labeled.
USP Reference standards á11ñ
USP Yohimbine Hydrochloride RS
Infrared Absorption á197Kñ
B:Thin-Layer Chromatographic Identification Test á201ñ
Dissolve 10mg of it in 1mLof methanol,add 1drop of ammonium hydroxide,and mix.
Developing solvent system:
methylene chloride,methanol,and ammonium hydroxide (90:14:1),in a saturated chamber.
Allow the plate to air-dry in a hood.Expose the dry plate for 30minutes to short-wavelength UVlight,then examine under long-wavelength UVlight:the size,intensity,and RF
value of the principal spot in the chromatogram obtained from the Test solution
correspond to those characteristics of the principal spot in the chromatogram obtained from the Standard solution.
C:Ultraviolet Absorption á197Uñ
10µg per mL.
0.1Nhydrochloric acid in methanol.
To 10mg of it add 3drops of sulfuric acid.Mix,and add 50mg of ammonium vanadate:a violet color is produced (differentiation from strychnine
,which produces a red color).Add 1mLof water:no color change occurs.
Specific rotation á781Sñ:
10mg per mL,in water,prepared by warming on a steam bath and allowing to cool.
Loss on drying á731ñ
Dry it at 105
for 2hours:it loses not more than 1.0%of its weight.
Use the chromatogram of the Assay preparation
obtained as directed in the Assay.
Calculate the percentage of each impurity in the portion of Yohimbine Hydrochloride taken by the formula:
in which ri
is the response of the individual impurity;and rs
is the sum of all the responses in the chromatogram:not more than 1.0%of any individual impurity is found,and the sum of all the impurities found is not more than 2.0%.
Prepare a mixture of water,dibasic sodium phosphate dihydrate solution (11.88g per L),and monobasic potassium phosphate solution (9.08g per L)(355:100:50).Add 4g of sodium dodecyl sulfate,and mix.Add 285mLof acetonitrile,and mix.Make adjustments if necessary (see System Suitability
under Chromatography á621ñ
Quantitatively dissolve an accurately weighed quantity of USP Yohimbine Hydrochloride RS
in methanol to obtain a solution having a known concentration of about 0.2mg per mL.
Transfer about 50mg of Yohimbine Hydrochloride,accurately weighed,to a 100-mLvolumetric flask,dilute with methanol to volume,and mix.Transfer 10.0mLof this solution to a 25-mLvolumetric flask,dilute with methanol to volume,and mix.
System suitability solution
Quantitatively dilute an accurately measured volume of the Standard preparation
with methanol to obtain a solution having a concentration of 0.40µg of USP Yohimbine Hydrochloride RS
Chromatographic system (see Chromatography á621ñ)
The liquid chromatograph is equipped with a 229-nm detector and a 4-mm ×12.5-cm column that contains 4-µm packing L7.The flow rate is about 2mLper minute.Chromatograph the System suitability solution
,and record the peak responses as directed for Procedure:
the main yohimbine peak gives a measurable response.Chromatograph the Standard preparation,
and record the peak responses as directed for Procedure:
the tailing factor is not more than 2.5;and the relative standard deviation for replicate injections is not more than 1%.
Separately inject equal volumes (about 10µL)of the Standard preparation
and the Assay preparation
into the chromatograph,record the chromatograms,and measure the areas for the major peaks.Calculate the quantity,in mg,of C21
·HCl in the portion of Yohimbine Hydrochloride taken by the formula:
in which C
is the concentration,in mg per mL,of USP Yohimbine Hydrochloride RS
in the Standard preparation;
are the yohimbine peak responses obtained from the Assay preparation
and the Standard preparation,
:Ian DeVeau,Ph.D.,Senior Scientist
:Volume No.29(6)Page 2005