Size-exclusion chromatographic determination of dextran sulfate in rat serum

A sensitive and selective method for the determination of dextran sulfate in rat serum has been developed. The analysis is suitable for quantitation of the drug and for monitoring molecular mass changes occurring during biotransformation. Dextran sulfate is resolved from higher molecular mass serum components by high-performance aqueous size-exclusion chromatography. The method has been validated for the direct injection of serum. Sensitive detection is achieved by post-column reaction of the polyanionic drug with the dye 1,9-dimethylmethylene blue. Components of serum which inhibit complex formation are separated chromatographically from dextran sulfate. Absorbance of the metachromatic complex is monitored at 525 nm.