Paraldehyde
;)
1,3,5-Trioxane,2,4,6-trimethyl-.
2,4,6-Trimethyl-s-trioxane [123-63-7].
»NOTE—Paraldehyde is subject to oxidation to form acetic acid.It may contain a suitable stabilizer.
Packaging and storage—
Preserve in well-filled,tight,light-resistant containers,preferably of Type Ior Type IIglass,holding not more than 30mL,at a temperature not exceeding 25
.Paraldehyde may be shipped in bulk containers holding a minimum of 22.5kg (50lb)to commercial drug repackagers only.
.Paraldehyde may be shipped in bulk containers holding a minimum of 22.5kg (50lb)to commercial drug repackagers only.
Labeling—
The label of all containers of Paraldehyde,including those dispensed by the pharmacist,includes a statement directing the user to discard the unused contents of any container that has been opened for more than 24hours.
NOTE—The label of bulk containers of Paraldehyde directs the commercial drug repackager to demonstrate compliance with the USPpurity tests for Paraldehyde immediately prior to repackaging,and not to repackage from a container that has been opened longer than 24hours.
Identification—
Heat it with a small quantity of 2Nsulfuric acid:acetaldehyde,recognizable by its pungent odor,is produced.
Congealing temperature á651ñ:
not lower than 11.
.
Distilling range,Method Iá721ñ—
It distills completely between 120and 126,a correction factor of 0.050per mm being applied as necessary.
and 126,a correction factor of 0.050per mm being applied as necessary.
Acidity—
To a solution of 6.0mLin 100mLof water add 5drops of phenolphthalein TS,and titrate with 1.0Nsodium hydroxide:not more than 0.50mLis required to produce a pink color (0.5%as acetic acid).
Chloride—
To 5mLof a solution (1in 10)add 1drop of nitric acid and 3drops of silver nitrate TS:no opalescence is produced immediately.
Sulfate—
To 5mLof a solution (1in 10)add 1drop of hydrochloric acid and 3drops of barium chloride TS:no turbidity is produced.
Limit of nonvolatile residue—
Heat 5.0mLin a small,tared evaporating dish on a steam bath:no disagreeable odor is noticeable as the last portions evaporate,and,when dried at 105for 1hour,not more than 3mg of residue remains (0.06%).
for 1hour,not more than 3mg of residue remains (0.06%).
Limit of acetaldehyde—
Place 100mLof water in a 250-mLconical flask,add 5.0mLof Paraldehyde,and shake the mixture gently until solution is complete.Add 5mLof hydroxylamine hydrochloride solution (3.5in 100).Shake the mixture gently for 30seconds,add methyl orange TS,and titrate immediately with 0.50Nsodium hydroxide.Perform a blank titration:the difference between the titers does not exceed 1mLof 0.50Nsodium hydroxide (0.4%).
Auxiliary Information—
Staff Liaison:Salvador C.Salado,M.S.,Scientist and Latin American Liaison
Expert Committee:(PA3)Pharmaceutical Analysis 3
USP28–NF23Page 1468
Phone Number:1-301-816-8165