| 摘要 |
<p>Calcium leucovorin (I) is prepd. by mixing anhydroleucovorin (II), an amine base and an aq. solvent. Then the mixt. is heated at pH 5-7 and an equimolar amt. of water-soluble Ca salt (III) (based on (II)) and isolating the (I). Because an amine is used for ring opening of (II), the (I) has lower impurity levels than when inorganic base is used. The (I) prod. meets U.S. Pharmacopeia specifications after being washed with water, and chromatographic purification etc. is not necessary. (I) is useful in dimininishing the toxicity and effects of overdoses of folic acid antagonists and for treating megaloblastic anaemias due to sprue, nutritional deficiency, pregnancy, infancy etc. and esp. for neutralising the toxic effects of methotrexate.</p> |
