Candelilla Wax - Definition, Identification, Impurities - USP 2025
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This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition
Issued and maintained by the United States Pharmacopeial Convention (USP)
1 DEFINITION
Candelilla Wax is the purified wax obtained from the leaves of the candelilla plant, Euphorbia antisyphilitica Zucc.
2 IDENTIFICATION
A. SPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197F
Sample: Use a thin film of melted Candelilla Wax.
Acceptance criteria: Meets the requirements
B. It meets the requirements of the test in Specific Tests for Melting Range or Temperature (741), Class II.
3 IMPURITIES
LEAD (251), Procedures, Procedure 1
Sample: 3.3 g
Control: 10 µg of lead from a Diluted standard lead solution (1 µg/mL of lead)
Analysis: Weigh the Sample into a porcelain dish, heat on a hot plate until completely charred, then heat in a muffle furnace at 480° for 8 h or overnight, and cool. Cautiously add 5 mL of nitric acid, evaporate to dryness on a hot plate, then heat again in the muffle furnace for exactly 15 min, and cool. Extract the ash with two 10-mL portions of water, filtering each extract into a separator. Leach any insoluble material on the filter with 6 mL of Ammonium citrate solution, 2 mL of Hydroxylamine hydrochloride solution, and 5 mL of water, adding the filtered washings to the separator. Continue as directed in (251), Procedure, beginning with "Add 2 drops of phenol red TS", and use 10 mL of Diluted standard lead solution for a control.
Acceptance criteria: The color of the Sample solution does not exceed that in the control, corresponding to NMT 3 µg/g.
4 SPECIFIC TESTS
MELTING RANGE OR TEMPERATURE (741), Procedures, Procedure for Class II: 68°-73°
FATS AND FIXED OILS (401), Procedures, Acid Value
Sample: 3 g
Analysis: Weigh the Sample in a 250-mL flask, add 50 mL of a mixture of isopropyl alcohol and toluene (5:4), attach the flask to a reflux condenser, and boil gently until the wax is completely dissolved. Examine the solution: no insoluble particles are present. Remove the flask from the condenser, add 1 mL of phenolphthalein TS, and titrate immediately with 0.5 N alcoholic potassium hydroxide VS to a faint, reddish-yellow color. [NOTE-Do not allow the solution to cool; titrate at a warm temperature after refluxing. After the titration, reserve the solution for use in the test for Saponification Value.]
Calculate the acid value as the number of mg of potassium hydroxide required to neutralize the free acids in 1 g of Candelilla Wax.
Acceptance criteria: 12-22
Change to read:
FATS AND FIXED OILS (401), Procedures, Saponification Value
Sample solution: Use the solution from the test for Acid Value.
Analysis: To the Sample solution add 15.0 mL of 0.5 N alcoholic potassium hydroxide VS, reflux for 3-4 h, and titrate the excess alkali with 0.5 N hydrochloric acid VS to a yellow-amber color. Perform a blank determination under the same conditions (see Titrimetry (541). Types of Titrations, Blank Corrections (CN 1-Aug-2024)). The saponification value is the summation of the ester value so obtained and the acid value obtained above.
Acceptance criteria: 43-65
5 ADDITIONAL REQUIREMENTS
PACKAGING AND STORAGE: Preserve in well-closed containers. No storage requirements specified.
USP REFERENCE STANDARDS (11)
USP Candelilla Wax RS
