» Propylhexedrine Inhalant consists of cylindrical rolls of suitable fibrous material impregnated with Propylhexedrine, usually aromatized, and contained in a suitable inhaler. The inhaler contains not less than 90.0 percent and not more than 125.0 percent of the labeled amount of C10H21N.
Packaging and storage Preserve in tight containers (inhalers), and avoid exposure to excessive heat.
Identification Place the contents of 1 inhaler in a glass-stoppered flask, add 50 mL of methanol, and allow to stand for 1 hour with frequent agitation. Filter, pressing out the roll on the filter. Add to the filtrate 1 N hydrochloric acid until it is slightly acid to moistened litmus paper, then add 30 mL of water, and evaporate to about 20 mL. Cool, transfer to a small separator, and shake with 10 mL of ether. Withdraw the water layer, warm it on a steam bath to expel any ether, and dilute to about 25 mL. From 10 mL of the solution, precipitate the propylhexedrine with trinitrophenol TS as directed in Identification test A under Propylhexedrine: the propylhexedrine picrate so obtained melts between 108 and 110 (see Melting Range or Temperature 741). [CautionPicrates may explode. ]
Assay Place the contents of 2 inhalers of Inhalant in the thimble of a continuous-extraction apparatus, and quickly assemble the apparatus. Rinse each of the emptied inhalers with about 20 mL of methanol, pouring the rinsings through the condenser into the extraction flask. Add through the condenser 20 mL to 30 mL of methanol, and extract for 15 to 20 cycles. Cool the extract, transfer it completely with the aid of small portions of methanol to a 100-mL volumetric flask, dilute with methanol to volume, and mix. To 50.0 mL of the solution add 25.0 mL of 0.1 N sulfuric acid VS, and evaporate to about 40 mL. Cool, add methyl red TS, and titrate the excess acid with 0.1 N sodium hydroxide VS. Each mL of 0.1 N sulfuric acid is equivalent to 15.53 mg of C10H21N.