Methoxyflurane
;)
Ethane,2,2-dichloro-1,1-difluoro-1-methoxy-.
2,2-Dichloro-1,1-difluoroethyl methyl ether [76-38-0].
»Methoxyflurane contains not less than 99.9percent and not more than 100.0percent of C3H4Cl2F2O.It may contain a suitable stabilizer.
Packaging and storage—
Preserve in tight,light-resistant containers,and avoid exposure to excessive heat.
Identification—
A:
The IRabsorption spectrum of a 1in 20solution in chloroform exhibits maxima only at the same wavelengths as that of a similar solution of USP Methoxyflurane RS.
B:
To 1mLin a test tube add 1mLof sulfuric acid:the specimen forms a layer over the acid (distinction from halothane).
C:
Cautiously heat the contents of the test tube from Identificationtest Bwith agitation:the interface disappears,and hydrofluoric acid is evolved (distinction from chloroform,trichloroethylene,and halothane).
Specific gravity á841ñ:
between 1.420and 1.425.
Acidity—
Shake 25mLwith 25mLof carbon dioxide-free water for 2minutes,and allow the layers to separate.Add 1drop of methyl red TSto the water extract,boil for 1minute,and titrate with 0.010Nsodium hydroxide:not more than 0.50mLof 0.010Nsodium hydroxide is required to produce a distinct yellow color.
Water,Method Iá921ñ:
not more than 0.1%.
Foreign odor—
Place 10mLon a dry watch glass,and allow it to evaporate spontaneously to about 1mL:no foreign odor is perceptible during the evaporation.To the remaining test specimen add a piece of odorless filter paper,and allow the paper to dry,checking it for foreign odor every few seconds during the drying period.As the last traces of odor leave the paper,a faint,characteristic odor may be detected for a few seconds,but no residual foreign odor is detected.
Limit of nonvolatile residue—
Allow 50mLto evaporate at room temperature in a tared evaporating dish,and dry the residue at 105
for 1hour:the weight of the residue does not exceed 1mg.
for 1hour:the weight of the residue does not exceed 1mg.
Assay—
Inject a volume of Methoxyflurane (30µLor less)into a suitable gas chromatograph (see Chromatography á621ñ)equipped with a thermal conductivity detector.Under typical conditions,the instrument contains a 4-mm ×3-m stainless steel column packed with liquid phase G11on support S1A,the column is maintained at a temperature of 100to 110,the injection port is maintained at about 150,and dry helium is used as the carrier gas at a flow rate of about 60mLper minute.Calculate the percentage purity by dividing 100times the area of the methoxyflurane peak by the sum of all the areas in the chromatogram.
to 110,the injection port is maintained at about 150,and dry helium is used as the carrier gas at a flow rate of about 60mLper minute.Calculate the percentage purity by dividing 100times the area of the methoxyflurane peak by the sum of all the areas in the chromatogram.
Auxiliary Information—
Staff Liaison:Karen A Russo,Ph.D.,Scientist
Expert Committee:(PA1)Pharmaceutical Analysis 1
USP28–NF23Page 1252
Phone Number:1-301-816-8379