Polyoxyl 40Stearate
Poly(oxy-1,2-ethanediyl),a-hydro-w-hydroxy-,octadecanoate.
Polyethylene glycol monostearate [9004-99-3].
»Polyoxyl 40Stearate is a mixture of the mono-esters and di-esters of Stearic Acid or Purified Stearic Acid with mixed polyoxyethylene diols,the average polymer length being equivalent to about 40oxyethylene units.
Packaging and storage—
Preserve in tight containers.
Identification,Infrared Absorption á197Mñ,on undried specimen.
Acid value á401ñ:
not more than 2.
Hydroxyl value á401ñ:
between 25and 40.
Saponification value á401ñ:
between 25and 35.
Water,Method Iá921ñ:
not more than 3.0%.
Heavy metals,Method IIá231ñ:
0.001%.
Free polyethylene glycols—
Transfer about 6g,accurately weighed,to a 500-mLseparator containing 50mLof ethyl acetate.Dissolve completely,then add 50mLof sodium chloride solution (29in 100),shake vigorously for 2minutes,and allow to separate for 15minutes.If separation is incomplete,carefully insert the separator into the well of a steam bath for short time intervals.Repeat this technique as many times as necessary to ensure the complete separation of the two phases.Cool,and drain the lower,aqueous,phase into a second 500-mLseparator,and extract the upper layer with a second 50-mLportion of sodium chloride solution (29in 100).Repeat the separation as before,including the steam bath technique to enhance complete separation.To the combined aqueous layers add 50mLof ethyl acetate,shake vigorously for 2minutes,and allow to separate as before.Drain the lower,aqueous phase into a third 500-mLseparator,and extract it with two 50-mLportions of chloroform,by shaking for 2minutes each time.Repeat the steam bath technique to ensure complete separation.Evaporate the combined chloroform extracts in a 150-mLbeaker on a steam bath,with the aid of a stream of nitrogen,to apparent dryness.Redissolve in about 15mLof chloroform,and transfer to a filter,collecting the filtrate in a 150-mLbeaker.Rinse the funnel with several small portions of chloroform,and evaporate the combined filtrate and rinsings,as described above,until no odor of chloroform or ethyl acetate is perceptible.Dry in vacuum at 60
for 1hour.Cool in a desiccator,and weigh:not less than 17%and not more than 27%of free polyethylene glycols is found.
for 1hour.Cool in a desiccator,and weigh:not less than 17%and not more than 27%of free polyethylene glycols is found.
Organic volatile impurities,Method Iá467ñ:
meets the requirements.
Auxiliary Information—
Staff Liaison:Catherine Sheehan,B.Sc.,Scientist
Expert Committee:(EMC)Excipients:Monograph Content
USP28–NF23Page 3061
Pharmacopeial Forum:Volume No.28(3)Page 720
Phone Number:1-301-816-8262