C10H12O5 212.20

Benzoic acid, 3,4,5-trihydroxy-, propyl ester.
Propyl gallate [121-79-9].

Packaging and storage— Preserve in tight containers, protected from light, and avoid contact with metals.

USP Reference standards 11— USP Propyl Gallate RS.

Identification—

Melting range 741: between 146 and 150.

Loss on drying 731— Dry it at 105 for 4 hours: it loses not more than 0.5% of its weight.

Residue on ignition 281: not more than 0.1%.

Heavy metals, Method II 231: 0.001%.

Organic volatile impurities, Method V 467: meets the requirements.

Residual solvents 467: meets the requirements.

Assay— Transfer about 100 mg of Propyl Gallate, accurately weighed, to a 250-mL volumetric flask, dissolve in about 100 mL of methanol, dilute with methanol to volume, and mix. Transfer 5.0 mL of this solution to a 200-mL volumetric flask, dilute with methanol to volume, and mix. Concomitantly determine the absorbances of this solution and a Standard solution of USP Propyl Gallate RS in methanol having a known concentration of about 10 µg per mL, in 1-cm cells at the wavelength of maximum absorbance at about 273 nm, with a suitable spectrophotometer, using methanol as the blank. Calculate the quantity, in mg, of C10H12O5 in the portion of Propyl Gallate taken by the formula: in which C is the concentration, in µg per mL, of USP Propyl Gallate RS in the Standard solution, and AU and AS are the absorbances of the solution of Propyl Gallate and the Standard solution, respectively.

Expert Committee : (EM105) Excipient Monographs 1

USP29–NF24 Page 3410

Phone Number : 1-301-816-8262