Novel cyclic phosphate prodrug approach for cytochrome P450-activated drugs containing an alcohol functionality.
OBJECTIVE
A cyclic phosphate prodrug of a descriptive molecule containing an alcohol functionality was designed, synthesized and characterized in vitro as a cytochrome P450 (CYP) -selective prodrug.


METHODS
To achieve efficient CYP-oxidation and prodrug bioconversion, 1,3-cyclic propyl ester of phosphate was designed to have a C4-aryl substituent and synthesized using phosphorus(III) chemistry. The two-step bioconversion of the cyclic phosphate prodrug was evaluated in vitro using human liver microsomes and recombinant CYP enzymes.


RESULTS
This cyclic phosphate prodrug underwent initial CYP-catalyzed oxidation and was mainly catalyzed by the CYP3A4 form. The hydroxylated product was slowly converted to a ring-opened intermediate, which subsequently transformed by beta-elimination reaction to a free phosphate. The free phosphate was further dephosphorylated by microsomal phosphatases, releasing the parent molecule with a free hydroxyl group. The cyclic phosphate was reasonably stable in buffer solutions at the pH range 1.0-9.0.


CONCLUSIONS
Since CYP enzymes reside predominantly in the liver and secondarily in the small intestine, the results indicate that cyclic phosphate prodrugs represent a very feasible liver- or intestinal-targeted drug delivery strategy for drug molecules containing an alcohol functionality. This may potentially improve the efficacy and the safety profile of the alcoholic parent drugs.
Huttunen
Kristiina M
KM
Department of Pharmaceutical Chemistry, University of Kuopio, 70211, Kuopio, Finland. Kristiina.Huttunen@uku.fi
Mähönen
Niina
N
Leppänen
Jukka
J
Vepsäläinen
Jouko
J
Juvonen
Risto O
RO
Raunio
Hannu
H
Kumpulainen
Hanna
H
Järvinen
Tomi
T
Rautio
Jarkko
J
D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism; D001711:Biotransformation; D002021:Buffers; D065731:Cytochrome P-450 CYP2C19; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D015195:Drug Design; D004355:Drug Stability; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006900:Hydroxylation; D066298:In Vitro Techniques; D008862:Microsomes, Liver / Q000201:enzymology; D006899:Mixed Function Oxygenases / Q000378:metabolism; D010755:Organophosphates / Q000138:chemical synthesis / Q000378:metabolism*; D010084:Oxidation-Reduction; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D011083:Polycyclic Compounds / Q000138:chemical synthesis / Q000378:metabolism*; D011355:Prodrugs / Q000138:chemical synthesis / Q000378:metabolism*; D020005:Propanols / Q000138:chemical synthesis / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism
D002021:Buffers; D010755:Organophosphates; D011083:Polycyclic Compounds; D011355:Prodrugs; D020005:Propanols; D011994:Recombinant Proteins; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D001189:Aryl Hydrocarbon Hydroxylases; C045793:CYP2C19 protein, human; D065731:Cytochrome P-450 CYP2C19; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; D010744:Phosphoric Monoester Hydrolases