C3H8O2S 108.16

1,2-Propanediol, 3-mercapto-.
3-Mercapto-1,2-propanediol [96-27-5].

Packaging and storage— Preserve in tight containers.

Specific gravity 841: between 1.241 and 1.250.

Refractive index 831: between 1.521 and 1.526.

pH 791: between 3.5 and 7.0, in a solution (1 in 10).

Water, Method II 921: not more than 5.0%.

Residue on ignition 281: not more than 0.1%.

Selenium 291: 0.003%, a 200-µL test specimen being used.

Heavy metals, Method II 231: 0.002%.

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

Residual solvents 467: meets the requirements.

Assay— Dissolve about 400 mg of Monothioglycerol, accurately weighed, in 50 mL of water, and titrate with 0.1 N iodine VS, adding 3 mL of starch TS as the endpoint is approached. Each mL of 0.1 N iodine is equivalent to 10.82 mg of C3H8O2S.

Expert Committee : (EM105) Excipient Monographs 1

USP29–NF24 Page 3377

Phone Number : 1-301-816-8262