Morphine-narcotine salts

The precipitate is filtered off, and the clear liquid concentrated, when a fresh deposit of meoonate of time will be formed. Filter again, wash the precipitate on the filter with a little cold water, and add the wasliings to the filtrate. This is now evaporated down to the consistence of sirup, and allowed to stand for some days. There is then obtained a crystalline mass— a double salt of morphin and codoin—and a dark mother-liquor, containing an acid meoonate of lime, a little morphin, and the narcetn, meoorun, narcotin, and paramorphin. 

The isolation of narcotine from opium is simplified by the fact that most of it remains in the water-insoluble residue when opium is processed for the manufacture of morphine. The narcotine is then extractable from this residue with dilute acids, and after regeneration from the extract it may be purified by recrystallization from ethanol (107). The acid oxalate, m.p. 174°, has also been used to separate it from its chief contaminant, namely, papaverine (92,108, 109). Its salt with camphorsulfonic acid is practically insoluble in water whereas that of the other opium salts are quite soluble (110). The free base may be quickly purified by passing a chloroform or benzene solution through a column of calcium hydroxide, most of the impurities being absorbed (HI). 

Two of the principal alkaloids of opium are morphine (4-21%) and a a-narcotine (noscapine) (4-8%) (63). These alkaloids occur partially bound to meconic acid, which is diagnostic for opium. Morphine (58) and its salts are classified as narcotic analgesics. Codeine (62) also occurs in opium, in the concentration range 0.7-2.5%. Most codeine (62) is prepared by methylation of morphine. 

In modem medicine, mily the purified opium alkaloids and their derivatives are commonly employed. Although the ripe poppy capsule can contain up to 0.5 % total alkaloids, opium represents a much concentrated form and up to 25 % of its mass is composed of alkaloids. Of the many (>40) alkaloids identified, some six represent almost all of the total alkaloid content. Actual amounts vary widely, e.g., morphine (4-21 %), codeine (0.8-2.5 %), thebaine (0.5-2.0 %), papaverine (0.5-2.5 %), noscapine (narcotine) (4—8 %), and narceine (0.1-2 %). A t3q>ical commercial sample of opium would probably have a morphine content of about 12 %. Powdered opium is standardized to contain 10 % of anhydrous morphine, usually by dilution with an approved diluent, e.g., lactose or cocoa husk powder. The alkaloids are largely combined in salt form with meconic acid, opium containing some 3-5 % of this material. Meconic acid is invariably found in opium but, apart from its presence in other Papaver species, has not been detected elsewhere. It gives a deep red-colored complex with ferric chloride, and this has thus been used as a rapid and reasonably specific test for opium. Of the main opium alkaloids, only morphine and narceine display acidic properties, as well as the basic properties due to the tertiary amine. Narceine has a carboxylic acid function, while morphine is acidic due to its phenolic hydroxyl. This acidity can be exploited for the preferential extraction of these alkaloids (principally morphine) from an organic solvent by partitioning with aqueous base (Table 15.6). 

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