Candelilla Wax
» Candelilla Wax is the purified wax obtained from the leaves of the candelilla plant, Euphorbia antisyphilitica.
Packaging and storage— Preserve in well-closed containers. No storage requirements specified.
A: Infrared Absorption 197F—Use a thin film of melted test specimen.
B: It meets the requirements of the test for Melting range.
Melting range, Class II 741: between 68.5 and 72.5.
Acid value 401 Accurately weigh about 3 g of Candelilla Wax into 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 about 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: the acid value is between 12 and 22.
Saponification value 401 To the solution from the test for Acid value, add 15.0 mL of 0.5 N alcoholic potassium hydroxide VS, reflux for 3 to 4 hours, 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 Residual Titrations under Titrimetry 541). The saponification value is the summation of the ester value so obtained and the acid value obtained above: it is between 43 and 65.
Limit of lead 251 Accurately weigh about 3.3 g of Candelilla Wax into a porcelain dish, heat on a hot plate until completely charred, then heat in a muffle furnace at 480 for 8 hours 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 minutes, 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 for Procedure under Lead 251 beginning with “Add two drops of phenol red TS”, and use 10 mL of Diluted Standard Lead Solution for a control containing a total of 10 µg of lead: the color of the sample solution does not exceed that in the control (3 µg per g).
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Monograph Hong Wang, Ph.D.
(EM205) Excipient Monographs 2
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 1182
Pharmacopeial Forum: Volume No. 30(3) Page 966