This section is from the book "Materia Medica Pharmacy, Pharmacology And Therapeutics", by W. Hale White. Also available from Amazon: Materia Medica Pharmacy, Pharmacology And Therapeutics..
Iodine is rarely employed for its antiseptic properties, as chlorine is cheaper. The preparations of iodine are in constant use as irritants and counter-irritants. Usually one or two coats of the liniment B. P., 1885, which contains iodine, 5; potassium iodide, 2; glycerin, 1; alcohol, 40, lightly painted on the skin, suffice; if more is used the inflammation is too severe. If it causes pain, it may be washed off with a solution of potassium iodide. The ointment, tincture and compound solution are much milder than the liniment, which is too strong for many persons. Preparations of iodine are frequently used as counter-irritants for chronic inflammation of joints, for pleurisy, chilblains, periostitis, and many other purposes. The mild preparations of iodine are applied over chronically inflamed lymphatic glands when the cause of the swelling cannot be removed. A decolorized tincture of iodine is prepared, consisting of iodine dissolved in alcohol, and decolorized by a strong solution of ammonia. Its strength is 1 in 40, nearly, and has the advantage of not staining the skin; but it contains no iodine, for ammonium iodide and iodate are formed. Therefore it is a much milder irritant than other iodine preparations. Any effect it may have is due to excess of ammonia. For its irritant effect the official tincture may be injected into a hydrocoele or a cyst to cause adhesive inflammation, and it has been injected into joints, abscesses, and the pleural cavity after empyema; but in such cases great care must be taken that the inflammation induced is not too severe, and this treatment is now very rarely used, for the cavities, being kept aseptic, heal up without it. The tincture, or, if it can be borne, the liquor B. P., which is iodine, 10; potassium iodide, 15; water, 200; is often used as an antiparasitic for ringworm. Coster's paste, which is sometimes employed for this disease, consists of iodine dissolved in light oil of wood tar (1 to 4). Morton's fluid, which is used as an injection for spina bifida, consists of iodine, 1; potassium iodide, 3; glycerin, 48. Two preparations are frequently employed in the treatment of diseases of women. These are: Churchill's tincture; iodine, 5; potassium iodide, 1; water, 8; alcohol, 24, and Battey's fluid; iodine, 2; pure carbolic acid, 1.
The vapor B. P., see p. 246 of iodine is occasionally inhaled for diseases of the lungs; but it probably does more harm than good. One or two minims, .06 to . 12 c.c. of the tincture in half an ounce, 15. c.c. of water are often given, quite empirically, every half hour, in cases of vomiting, and sometimes with distinct benefit. Preparations of seaweed have among uneducated persons a reputation for reducing obesity.
If they have any such action it is probably because the iodine, chlorine and bromine in them set up such dyspepsia that the proper digestion and absorption of food are prevented. Extracts of Fucus vesiculosus, the bladderwrack or seawrack, have been used, and are the basis of some quack preparations.
I. Potassii Iodidum. - Potassium Iodide. KI=l65.56.
Dissolve Iodine in a hot solution of Potassa in distilled water. 3l2+6Kho=5KI+Kio3+3H2O. Evaporate and heat the residue with Charcoal; the Oxygen of the Iodate is carried off as Carbonic Oxide. Kio3 +C3=KI+3CO. Dissolve in boiling water, filter, wash and crystallize.
Colorless, transparent or translucent, cubical crystals, or a white, granular powder, having a peculiar, faint, iodine-like odor, and a pungent, saline, afterwards bitter taste. •Solubility. - In 0.75 part of water; in 18 of Alcohol; in 2.5 of Glycerin.
Bismuth subnitrate, sweet spirit of nitre, liquorice, and preparations containing starch.
Iodates and free alkalies.
Dose, 5 to 60 gr.; .30 to 4.00 gm., or more.