TY - JOUR T1 - PHYSICAL AND CHEMICAL PROPERTIES OF SODIUM IODOBISMUTHITE, A SOLUBLE COMPOUND OF ELECTRONEGATIVE BISMUTH FOR USE IN THE TREATMENT OF SYPHILIS JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 427 LP - 467 VL - 45 IS - 4 AU - CHAS. GURCHOT AU - P. J. HANZLIK AU - JEAN SPAULDING Y1 - 1932/08/01 UR - http://jpet.aspetjournals.org/content/45/4/427.abstract N2 - The main part of our paper has dealt with an attempt at preparation and identification of sodium iodobismuthite, an inorganic compound of bismuth and iodine differing in type and properties from bismuth compounds in current use. The following is a brief summary of the essential points relative to the validity of the claims. From the method of preparation, the general properties of the product, such as color, crystalline structure, solubility, chemical reactions and electrical migration and the elementary composition, there seems to be no doubt that a compound has been prepared by us which is sodium iodobismuthite, containing a complex anion of bismuth and iodine. As to the choice of a formula, it was suggested from the chemical analysis, supplemented by theoretical deductions. Molecular weights could not be determined for lack of facilities to use a suitable solvent in which the compound would not ionize, polymerize or decompose. Acetic acid was tried, but unsuccessfully. No values were available for ionization constants. The results of chemical analysis, except volatile matter, were compatible with the formula Na2BiI5·4H2O. In the modified method of synthesis, the presence of a hydroxyl (OH) group, replacing 1 iodine atom, is eliminated, but the compound obtained by crystallization from alcohol, according to the old method, may have the formula Na2BiI4(OH)·4 or 6H2O. The revised method gives a compound of more uniform bismuth content, which alone would justify its use. The iodobismuthite prepared does not have the properties of a double salt. The results of migration experiments, which showed the existence of a complex, electronegative ion, sustain this, and also certain chemical reactions and tests which failed to establish the presence of the bismuth ion alone. That is, the compound is not a double salt of bismuth. Precipitation on treatment with water means hydrolysis, but this is not characteristic of double salts, for there is a considerable number of double salts which do not hydrolyze, namely carnallite, the alums, etc. Moreover, the soluble arsenites and antimonites hydrolyze and they are not double salts. From our results, iodobismuthite should be regarded as containing a complex bismuth anion containing iodine. As to oxidizing properties, the iodobismuthite should not be expected to possess these any more than an arsenite which is a powerful reducing agent. Lack of oxidizing power, therefore, would not be against considering the product as an anionic or acidic bismuth compound. lodobismuthite is an iodine derivative of an acid bismuth compound, namely, bismuthite. This was sufficiently discussed under nomenclature in the text. Electronegativity (anionic character) of heavy metals may be fundamentally significant for better absorption and cerebral penetration of heavy metals as is the case with halides. Theoretically, iodobismuthite should fit in with this conception, and practical results, being reported elsewhere, sustain it. Electropositive bismuth, as in sodium bismuth tartrate (in cane sugar solution) may become partly electronegative under suitable conditions in vitro. In serum, both sodium bismuth tartrate and sodium bismuth thioglycollate yielded electronegative bismuth. These changes indicate the complex behavior of bismuth compounds, which may be significant in the behavior of bismuth under biological conditions. The principle of electronegativity may be more intimately related to cerebral penetration of bismuth in general than is realized. Certain pharmacological actions of potassium iodomercuriate (K2HgI4), as compared with those of mercuric iodide or mercuric chloride, show differences according to their ionic characteristics. For instance, the toxicity of the mercury in a complex anionic state is much less than that of mercury in the cationic state. This has been recently shown by Baas-Becking (23). Baas-Becking found that the flagellate Dunaliella could tolerate 100 times the concentration of mercury, when the organism was suspended in a solution of potassium iodomercuriate (K2HgI4; concentration of Hg, 1.1 x 10–3) than when it was suspended in a solution of mercuric iodide (HgI2) in potassium chloride (concentration of Hg, 7 x 10–5). A lower toxicity was also observed with a solution of mercuric chloride in sodium chloride, a common ion phenomenon. If these relations hold for the amphoteric ions of mercury, they are conceivably true for amphoteric ions of bismuth compounds. These theoretical considerations are not idle speculation. They appear to be sustained by experimental results on general actions, toxicity, etc. The considerable amount of details and facts presented in this report still indicates the desirability of further work on the chemistry of iodobismuthite and of its interesting homologues. ER -