Packaging and storage
Preserve in tight containers.
Heat it with water for several minutes, cool, and add 1 or 2 drops of ferric chloride TS
: a violet-red color is produced.
Loss on drying 731
Dry it over silica gel for 5 hours: it loses not more than 0.5% of its weight.
Substances insoluble in sodium carbonate TS
A solution of 500 mg in 10 mL of warm sodium carbonate TS is clear.
Boil 1.5 g with 75 mL of water for 5 minutes, cool, add sufficient water to restore the original volume, and filter. A 25-mL portion of the filtrate shows no more chloride than corresponds to 0.10 mL of 0.020 N hydrochloric acid (0.014%).
Dissolve 6.0 g in 37 mL of acetone, and add 3 mL of water. Titrate potentiometrically with 0.02 M lead perchlorate, prepared by dissolving 9.20 g of lead perchlorate in water to make 1000 mL of solution, using a pH meter capable of a minimum reproducibility of ±0.1 mV (see pH 791
) and equipped with an electrode system consisting of a lead-specific electrode and a silversilver chloride reference glass-sleeved electrode containing a solution of tetraethylammonium perchlorate in glacial acetic acid (1 in 44) (see Titrimetry 541
): not more than 1.25 mL of 0.02 M lead perchlorate is consumed (0.04%). [NOTE
After use, rinse the lead-specific electrode with water, drain the reference electrode, flush with water, rinse with methanol, and allow to dry.]
Dissolve 2 g in 25 mL of acetone, and add 1 mL of water. Add 1.2 mL of thioacetamideglycerin base TS and 2 mL of pH 3.5 Acetate Buffer
(see Heavy Metals 231
), and allow to stand for 5 minutes: any color produced is not darker than that of a control made with 25 mL of acetone and 2 mL of Standard Lead Solution
(see Heavy Metals 231
), treated in the same manner. The limit is 10 µg per g.
Limit of free salicylic acid
Dissolve 2.5 g in sufficient alcohol to make 25.0 mL. To each of two matched color-comparison tubes add 48 mL of water and 1 mL of a freshly prepared, diluted ferric ammonium sulfate solution (prepared by adding 1 mL of 1 N hydrochloric acid to 2 mL of ferric ammonium sulfate TS
and diluting with water to 100 mL). Into one tube pipet 1 mL of a standard solution of salicylic acid in water, containing 0.10 mg of salicylic acid per mL. Into the second tube pipet 1 mL of the 1 in 10 solution of Aspirin. Mix the contents of each tube: after 30 seconds, the color in the second tube is not more intense than that in the tube containing the salicylic acid (0.1%).
Organic volatile impurities, Method IV 467:
meets the requirements.
Place about 1.5 g of Aspirin, accurately weighed, in a flask, add 50.0 mL of 0.5 N sodium hydroxide VS, and boil the mixture gently for 10 minutes. Add phenolphthalein TS
, and titrate the excess sodium hydroxide with 0.5 N sulfuric acid VS. Perform a blank determination (see Residual Titrations
under Titrimetry 541
). Each mL of 0.5 N sodium hydroxide is equivalent to 45.04 mg of C9
: Clydewyn M. Anthony, Ph.D., Scientist
Expert Committee : (MDCCA05) Monograph Development-Cough Cold and Analgesics
USP29NF24 Page 196
: Volume No. 30(4) Page 1164
Phone Number : 1-301-816-8139