A: Infrared Absorption 197K.

B: The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.

C: A solution (1 in 100) meets the requirements of the tests for Chloride 191.

Standard iron solution— Use the Standard Iron Solution prepared as directed under Iron 241.

Hydroxylamine solution— Dissolve 5 g of hydroxylamine hydrochloride in 50 mL of water.

Triazine solution— Dissolve 125 mg of 2,4,6-tri-(2-pyridyl)-S-triazine in 100 mL of methanol.

Standard solution— Into a 50-mL color-comparison tube pipet 1 mL of Standard iron solution, add 42.0 mL of water, and mix.

Test solution— Into a 50-mL color-comparison tube add 2.0 g of Dipivefrin Hydrochloride, 43.0 mL of water, and mix.

Procedure— To each of the tubes containing the Standard solution and the Test solution, add 5.0 mL of Hydroxylamine solution, 2.0 mL of Triazine solution, and mix: the color of the solution from the Test solution is not darker than that of the solution from the Standard solution.

Change to read:

Mobile phase— Prepare a mixture of acetonitrile, 0.014 M sodium dodecyl sulfate, and glacial acetic acid (24:15:1).

Standard preparation— Dissolve a suitable quantity of USP Dipivefrin Hydrochloride RS, accurately weighed, in 0.0015 N hydrochloric acid to obtain a solution having a known concentration of about 5 mg per mL.

Assay preparation— Dissolve a suitable quantity of Dipivefrin Hydrochloride, accurately weighed, in 0.0015 N hydrochloric acid to obtain a solution having a known concentration of about 5 mg per mL.USP32

Chromatographic system (see Chromatography 621)— The liquid chromatograph is equipped with a 254-nm detector and a 4-mm × 30-cm column that contains packing L1. The flow rate is about 2 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the column efficiency is not less than 500 theoretical plates; the tailing factor for the major peak is not more than 1.5; and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 20 µL) of the Standard preparation and the Assay preparation into the chromatograph by means of a suitable microsyringe or sampling valve, record the chromatograms, and measure the responses for the major peaks. Calculate the percentageUSP32 of C19H29NO5·HCl in the portion of Dipivefrin Hydrochloride taken by the formula: in which CS is the concentration, in mg per mL, of dipivefrin hydrochloride in the Standard preparation; CU is the concentration, in mg per mL, of dipivefrin hydrochloride in the Assay preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.USP32