Evaluation, synthesis and characterization of tacrolimus impurities.

Patrizia Ferraboschi, Diego Colombo, Maria De Mieri, Paride Grisenti

Index: J. Antibiot. 65(7) , 349-54, (2012)

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Abstract

Tacrolimus is an immunosuppressant macrolactam of fermentative origin. By means of HPLC, LC-MS and NMR analyses, coupled with the reference standard synthesis, the main impurities of tacrolimus bulk drug samples were identified and their chemical-physical properties reported. Known ascomycin and tautomers I and II were detected. The correct relative retention time HPLC value of 39,40-dihydro tacrolimus was established. The not described 23,24-anhydro derivative was detected and completely characterized. A full characterization of ascomycin and 39,40-dihydro tacrolimus was also reported.