Detailed Product Description

Hypromellose Phthalate
Hypromellose Phthalate is a monophthalic acid ester of hydroxypropyl
methylcellulose. It contains methoxy (OCH3), hydroxypropoxy
(OCH2CHOHCH3), and phthalyl (o-carboxybenzoyl, C8H5O3) groups. It
contains not less than 21.0 percent and not more than 35.0 percent of
phthalyl groups, calculated on the anhydrous basis.
Packaging and storage Preserve in tight containers.
Labeling Label it to indicate its viscosity and its nominal phthalyl content.
USP Reference standards 11
USP Hypromellose Phthalate RS.
Identification, Infrared Absorption 197K Do not dry specimens.
Viscosity 911 Dissolve 10 g, previously dried at 105 for 1 hour, in 90 g of a mixture of
equal weights of methanol and methylene chloride by mixing and shaking: the viscosity,
determined at 20 ± 0.1 (see Procedure for Cellulose Derivatives under Viscosity 911 ), is
not less than 80% and not more than 120% of that indicated by the label.
Water, Method I 921 : not more than 5.0%.
Residue on ignition 281 : not more than 0.20%.
Chloride 221 Dissolve 1.0 g in 40 mL of 0.2 N sodium hydroxide, add 1 drop of
phenolphthalein TS, and add 2 N nitric acid dropwise, with stirring, until the red color is
discharged. Add an additional 20 mL of 2 N nitric acid with stirring. Heat on a water bath, with
stirring, until the gel-like precipitate formed becomes granular. Cool the mixture, and
centrifuge. Separate the liquid phase, and wash the residue with three successive 20-mL
poHTions of water, separating the washings by centrifuging. Dilute the combined liquids with
water to 200 mL, mix, and filter. A 50-mL poHTion of the filtrate so obtained shows no more
chloride than a control solution made by treating 0.50 mL of 0.01 N hydrochloric acid with 10
mL of 0.2 N sodium hydroxide, adding 7 mL of 2 N nitric acid, and diluting with water to 50 mL
(0.07%).
Heavy metals, Method II 231 : 0.001%.
Limit of free phthalic acid
Mobile phase Prepare a filtered and degassed mixture of 0.1 M cyanoacetic acid and
acetonitrile (85:15). Make adjustments if necessary (see System Suitability under
Chromatography 621 ).
Standard solution Transfer about 12.5 mg of phthalic acid, accurately weighed, to a 250-mL
volumetric flask, add about 125 mL of acetonitrile, and mix to dissolve. Add 25 mL of water,
dilute with acetonitrile to volume, and mix.
Test solution Transfer about 200 mg of Hypromellose Phthalate, accurately weighed, to a
100-mL volumetric flask, add about 50 mL of acetonitrile, and sonicate to dissolve paHTially.
Add 10 mL of water, and sonicate to dissolve. Cool to room temperature, dilute with acetonitrile
to volume, and mix.
Chromatographic system The liquid chromatograph is equipped with a 235-nm detector and
a 4.6-mm × 25-cm column that contains packing L1 with a high carbon load. The flow rate is
about 2.0 mL per minute. Chromatograph the Standard solution, and record the peak
responses as directed for Procedure: the relative standard deviation for replicate injections is
not more than 1.0%.
Procedure Separately inject equal volumes (about 10 μL) of the Standard solution and the
Test solution into the chromatograph, record the chromatograms, and measure the peak
responses. Calculate the percentage of phthalic acid in the poHTion of Hypromellose Phthalate
taken by the formula:
10(C / W)(rU / rS)