Biomimetic oxidation is a novel and efficient means of producing preparative (multi-milligram) quantities of oxidative (Phase I) metabolites. It uses metalloorganic complexes that mimic the active site heme of cytochrome P450 (CYP) enzymes. Basically, it’s a protein-free, heme-like catalyst. In the presence of an oxygen donor such as H₂O₂, a reactive species is generated that can insert oxygen into a parent compound.

What are the advantages of the biomimetic approach?

• No solubility limitations for parent compound or catalyst due to the use of pure organic solvents
• Non-enzymatic catalysts are more rugged and can be used at higher concentrations than enzymes
• Versatile: does not depend on the presence and continuous activity of any particular CYP
• Flexible: reactants and conditions can be optimized to produce the biological metabolite(s) of interest
  • Initially, liver microsomes are used in parallel with the biomimetic system to generate biological metabolites
• Easier downstream purification of metabolites

The yield of biomimetically generated metabolites is sufficient to perform in vitro testing for drug-drug interaction potential:

P-gp Substrate Assessment

	A-B  Papp (x10-6cm/sec)	B-A  Papp (x10-6cm/sec)	Efflux Ratio	P-gp Substrate
Ritonavir	0.3	37.9	122	Yes
M1a-Rit	< 0.8	8.84	> 100	Yes
M2-Rit	0.21	1.74	8.3	Weaker
Clozapine	23.6	26.5	1.1	No
Des-Me Cloz	3.74	63.2	16.9	Yes

The desmethyl metabolite of clozapine, which was produced biomimetically, was identified as a substrate of the efflux transporter, P-glycoprotein, based on its bidirectional permeability in an in vitro cell monolayer assay. As such, it could be involved in drug-drug interactions in vivo, and that potential safety liability could not have been predicted based on studying the parent compound alone.

A detailed description of biomimetic metabolite generation and characterization can be found by clicking on the Assay Data Sheet in the Related Literature section below.

Please contact Absorption Systems if you are interested in biomimetic oxidation.