| 摘要 |
A method of preparing an anti-malignant tumor agent comprising a mixture of poly L-lactates that are cyclic and linear oligomers having degrees of condensation of 3 to 23, the method comprising dehydration condensation of L-lactic acid in a nitrogen atmosphere under stepwise reduced pressure and at an increasing temperature, drying ethanol- and methanol-soluble components in the resulting reaction solution under reduced pressured, subjecting the product to chromatography on a reverse phase ODS column, and after elution with 25 to 50% aqueous acetonitrile at pH 2.0, giving the mixture of poly L-lactates as a fraction eluted with 100% acetonitrile at pH 2.0.
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