Propoxycaine Hydrochloride
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C16H26N2O3·HCl 330.85

Benzoic acid, 4-amino-2-propoxy-, 2-(diethylamino)ethyl ester, monohydrochloride.
2-(Diethylamino)ethyl 4-amino-2-propoxybenzoate monohydrochloride [550-83-4].
» Propoxycaine Hydrochloride, dried at 105 for 3 hours, contains not less than 98.0 percent and not more than 102.0 percent of C16H26N2O3·HCl.
Packaging and storage— Preserve in well-closed, light-resistant containers.
B: Ultraviolet Absorption 197U
Solution: 10 µg per mL.
Medium: water.
Absorptivities at 303 nm, calculated on the dried basis, do not differ by more than 3.0%.
C: A solution (1 in 100) responds to the tests for Chloride 191.
Melting range, Class I 741: between 146 and 151.
Loss on drying 731 Dry it at 105 for 3 hours: it loses not more than 0.5% of its weight.
Residue on ignition 281: not more than 0.2%.
Chromatographic purity—
Solvent— Prepare a mixture of chloroform and methanol (9:1).
Standard preparations— Dissolve a quantity of USP Propoxycaine Hydrochloride RS in Solvent, and dilute quantitatively, and stepwise if necessary, with Solvent to obtain a solution containing 0.5 mg per mL. Dilute quantitatively with Solvent to obtain Standard preparations having the following compositions:
Standard preparation Dilution Concentration (mg RS per mL) Percentage (%, for comparison with test specimen)
A 1 in 2 0.25 0.5
B 1 in 5 0.10 0.2
C 1 in 10 0.05 0.1
Test preparation— Dissolve an accurately weighed quantity of Propoxycaine Hydrochloride in Solvent to obtain a solution containing 50 mg per mL.
Procedure— Apply separately 5 µL of the Test preparation and 5 µL of each Standard preparation to a suitable thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel mixture. Position the plate in a chromatographic chamber, and develop the chromatograms in a solvent system consisting of a mixture of chloroform, methanol, and isopropylamine (96:2:2) until the solvent front has moved about three-fourths of the length of the plate. Remove the plate from the developing chamber, mark the solvent front, and allow the solvent to evaporate, with the aid of warm circulating air. Examine the plate under short-wavelength UV light, and again after exposing the plate to iodine vapors for a few minutes and spraying it with 7 N sulfuric acid. In each instance, compare the intensities of any secondary spots observed in the chromatogram of the Test preparation with those of the principal spots in the chromatograms of the Standard preparations: no secondary spot is more intense than the principal spot obtained from Standard preparation A (0.5%), and the sum of the intensities of all secondary spots obtained from the Test preparation does not exceed 1.0%.
Assay— Dissolve about 500 mg of Propoxycaine Hydrochloride, previously dried and accurately weighed, in 200 mL of ice-cold water containing 1 g of potassium bromide and 2.5 mL of hydrochloric acid, and titrate with 0.1 M sodium nitrite VS, using starch iodide paper as an external indicator. Perform a blank determination, and make any necessary correction. Each mL of 0.1 M sodium nitrite is equivalent to 33.09 mg of C16H26N2O3·HCl.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Daniel K. Bempong, Ph.D.
Senior Scientist
(MDPS05) Monograph Development-Pulmonary and Steroids
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 3414
Pharmacopeial Forum: Volume No. 30(6) Page 2032