Morphinae Acetas, B.P. Morphine Acetate.
Related entries: Opium - Poppy Capsules - Cotarnine - Cotarnine Hydrochloride - Morphine - Morphine Acetate - Morphine Hydrochloride - Morphine Sulphate - Morphine Tartrate - Narceine - Narcotine - Red poppy petals - Meconic acid
C19H23NO5. 3H2O = 399.242.
Morphine acetate, C17H19NO3, C2H4O2, 3H2O, may be prepared by neutralising freshly precipitated morphine, diffused in water, with acetic acid, evaporating on a water-bath until the solution solidifies on cooling, and finally, carefully drying the salt at a gentle heat when it may be powdered. It cannot be dried without some little decomposition occurring, acetic acid being liberated. The U.S.P. states that it should contain a minute quantity of free acetic acid to prevent decomposition. It occurs as a white or yellowish-white, amorphous or crystalline powder, having a faintly acetous odour, especially when the vessel containing it is freshly opened. Samples which have been kept for any length of time become basic from loss of acetic acid, and brownish in colour. It has a bitter taste. In making aqueous solutions a little free acetic acid is usually required to replace that lost during spontaneous decomposition. The alcoholic solution when mixed with ether deposits crystals of the base, free acetic acid remaining in solution. When heated, the salt loses water and acetic acid, and melts at about 200°. In neutral solutions ferric chloride produces a blue colour, which is destroyed by acids, alcohol, or by heating. Morphine acetate should be kept in well-stoppered, amber-coloured bottles.
Soluble in water (1 in 2.5), alcohol (1 in 100), glycerin (1 in 5); insoluble in ether.
Action and Uses.—Morphine acetate has the general medicinal properties of the salts of morphine (see Morphina), but is not so much used as formerly, owing to the tendency both of the salt and its solutions to undergo change; the tartrate is now generally preferred. The acetate is employed in the preparation of the official Liquor Morphinae Acetatis, a fairly stable solution which, however, darkens slightly in colour on keeping. Morphine acetate is incompatible with alkalies, alkali earths, vegetable astringents, and salts of the heavy metals. In cases of poisoning by morphine acetate the antidotes are those of morphine.
Dose.—8 to 30 milligrams (⅛ to ½ grain).
PREPARATIONS.
- Liquor Morphinae Acetatis, B.P.—SOLUTION OF MORPHINE ACETATE.
- Morphine acetate, 1; diluted acetic acid, 2; alcohol, 25; distilled water, sufficient to produce 100. Mix the alcohol with 25 of the water, add the acid, dissolve the morphine acetate in the mixture, and add sufficient distilled water to make up to the required volume. This preparation has the same action as other solutions of morphine, and is used for similar purposes. Dose.—½ to 4 mils (10 to 60 minims).
- Pastillus Morphinae B.P.C.—MORPHINE PASTILLE. 1/30 grain.
