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Pharmacokinetics of Darolutamide, its Diastereomers and Active Metabolite in the Mouse: Response to Saini NK et al. (2020)

[ Vol. 14 , Issue. 1 ]


Pirjo Nykänen, Timo Korjamo, Hille Gieschen, Christian Zurth and Mikko Koskinen*   Pages 9 - 16 ( 8 )


Background: Saini et al. recently investigated the pharmacokinetics of darolutamide and its diastereomers in vitro and in vivo in Balb/c mice, reporting higher levels of (S,S)-darolutamide than (S,R)-darolutamide following intravenous or oral dosing, and interconversion of (S,R)-darolutamide to (S,S)-darolutamide.

Objective: To present our in vitro and in vivo studies of darolutamide pharmacokinetics in mice, which contrast with the findings of Saini et al.

Methods: Nude male Balb/c mice were orally dosed for 7 days with 25, 50, or 100 mg/kg of darolutamide twice daily. Pharmacokinetic parameters in plasma and tissue samples were assessed by liquid chromatography-tandem mass spectrometry. Metabolism and interconversion of darolutamide and its diastereomers were investigated in cryopreserved Balb/c mouse hepatocytes. Protein binding was determined in plasma samples by equilibrium dialysis.

Results: On day 7, Cmax was reached 30 min after the last dose. Rapid formation and greater exposure of keto-darolutamide versus darolutamide were observed. Plasma exposure of (S,R)-darolutamide was 3-5-fold higher than that of (S,S)-darolutamide. The fraction of unbound keto-darolutamide was almost 6-fold lower than for darolutamide.

In mouse hepatocytes, the conversion of (S,S)- to (S,R)-darolutamide was observed, but the conversion of (S,R)- to (S,S)-darolutamide was not detectable. Back-formation of keto-darolutamide to both diastereomers occurred at low levels.

Conclusion: The darolutamide diastereomer ratio changes upon administration in mice and other species due to interconversion through keto-darolutamide. This is not considered clinically relevant since both diastereomers and keto- darolutamide are pharmacologically similar in vitro. Based on the high protein binding of keto-darolutamide, its contribution in vivo in humans is considered low.


Darolutamide, pharmacokinetics, mice, diastereomer, interconversion, metabolism.


Orion Corporation, Orion Pharma, Espoo, Orion Corporation, Orion Pharma, Espoo, Bayer AG, Berlin, Bayer AG, Berlin, Orion Corporation, Orion Pharma, Espoo

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