| 摘要 |
Novel xanthosine salts, crystal and solute polymorphs of xanthosine and crystal and solute polymorphs of xanthosine salts. Also, a method of preparing a crystal polymorph of xanthosinate comprising: providing a solvent; adding to the solvent a quantity of xanthosine and an equimolar amount of a strong base; heating the solvent, base and xanthosine at a predetermined rate to a temperature sufficient to cause the xanthosine to go into solution and to overcome the energy barriers which prevent the conversion of the xanthosine to another polymorphic configuration; precipitating the xanthosine salt; cooling the salt at a predetermined rate for a predetermined period of time; and completely lyophilizing the salt. Another method of preparing a crystal polymorph of a xanthosine salt identical to this method, except that the heat generated by the neutralization reaction is the only source of heat. Also, a method of preparing a xanthosinate solute polymorph comprising dissolving a xanthosinate crystal polymorph in a solvent and methods of preparing a solute polymorph of a xanthosinate which are identical to the above two methods for preparing crystal polymorphs, except that the precipitation and lyophilization steps are eliminated. Finally, compositions for modulating the immune response of an animal comprising an amount of a polymorph of xanthosine or of a polymorph of a xanthosine salt effective to modulate the immune response of the animal, and methods of using these compositions to modulate the immune response of an animal. |
