Hydroxypropyl Cellulose Ocular System
» Hydroxypropyl Cellulose Ocular System contains not less than 85.0 percent and not more than 115.0 percent of the labeled amount of Hydroxypropyl Cellulose. It contains no other substance. It is sterile.
Packaging and storage Preserve in single-dose containers, at a temperature not exceeding 30.
USP Reference standards 11
USP Hydroxypropyl Cellulose RS.
Identification Prepare a 1 in 100 solution in methanol, based on the labeled amount of Hydroxypropyl Cellulose. Evaporate 2 drops of the solution on a silver chloride plate so that it forms a thin film: the IR absorption spectrum of the film so obtained exhibits maxima only at the same wavelengths as that of a similar preparation of USP Hydroxypropyl Cellulose RS.
Sterility 71: meets the requirements.
Weight variation Determine the weight of each of a sufficient number of Systems. Not more than 1 out of 20 varies more than 25% from the average or, failing that, not more than 6 out of 60 (including the original 20) vary more than 25% (but none more than 35%) from the average weight.
Standard preparation Dissolve with agitation an accurately weighed quantity of USP Hydroxypropyl Cellulose RS in water to obtain a solution having a known concentration of about 0.05 mg per mL.
Assay preparation Transfer a sufficient number of Ocular Systems, to provide about 25 mg of hydroxypropyl cellulose, to a 500-mL volumetric flask, add about 250 mL of water, and dissolve with agitation on a mechanical shaker. Dilute with water to volume, and mix.
Procedure Separately pipet 2 mL of the Standard preparation, the Assay preparation, and water, to provide a blank, into individual 50-mL centrifuge tubes. Add to each tube 6.0 mL of a 1 in 2000 solution of anthrone in sulfuric acid, and mix on a vortex mixer. After 40 minutes, again mix, and concomitantly determine the absorbances of the solutions obtained from the Standard preparation and the Assay preparation at 620 nm, with a suitable spectrophotometer, against the solution from the blank. Calculate the quantity, in mg, of hydroxypropyl cellulose in each Ocular System taken by the formula:
(500)(C / N)(AU / AS)in which C is the concentration, in mg per mL, of USP Hydroxypropyl Cellulose RS in the Standard preparation; N is the number of Ocular Systems taken for the Assay; and AU and AS are the absorbances of the solutions from the Assay preparation and the Standard preparation, respectively.
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USP32NF27 Page 2594