Generation of statin drug metabolites through electrochemical and enzymatic oxidations

Abstract

The generation of key drug metabolites for the purpose of their complete structural characterization, toxicity testing, as well as to serve as standards for quantitative studies, is a critical step in the pharmaceutical discovery and development cycle. Here, we utilized electrochemistry/mass spectrometry for the detection and subsequent generation of six phase I metabolites of simvastatin and lovastatin. Both simvastatin and lovastatin are widely used for the treatment of hypercholesterolemia. There are known drug-drug interaction issues of statin therapy, and it has been suggested that the oxidative metabolites may contribute to the cholesterol-lowering effect of both statins. Of the known phase I metabolites of simvastatin and lovastatin, none are commercially available, and chemical means for the synthesis of a very few of them have been previously reported. Here, we report that electrochemical oxidation of less than 1 mg each of simvastatin and lovastatin led to the generation of three oxidative metabolites of each parent to allow complete nuclear magnetic resonance characterization of all six metabolites. The yields obtained by the electrochemical approach were also compared with incubation of parent drug with commercially available bacterial mutant CYP102A1 enzymes, and it was found that the electrochemical approach gave higher yields than the enzymatic oxidations for the generation of most of the observed oxidative metabolites in this study.

Optimization of reaction parameters for the electrochemical oxidation of lidocaine with a Design of Experiments approach

“…Other metabolites, namely the N-oxide and aromatic hydroxylation products, were also monitored but were either absent (hydroxylations) or obtained in low and irreproducible yields (N-oxide). Three continuous range factors, pH (3)(4)(5)(6)(7)(8)(9)(10)(11)(12), concentration (10-1000 mM), and potential Table 1 are shown in Fig. 2 revealing that by far the highest amount of Ndealkylation product was obtained in experiment 12 corresponding to a pH of 12 and a potential of 1.5 V in combination with a low starting concentration (10 mM) and a glassy carbon electrode.…”

“…However, these methods are not adequate to produce metabolites in sufficiently large quantities for follow-up studies [6]. In order to characterize the structure and study the toxicology of metabolites, it is necessary to have quantities in excess of 1 mg [7,8]. While organic synthesis is the standard approach, an emerging technique to produce oxidative metabolites is electrochemistry (EC), which can be combined with mass spectrometry (EC-MS) for product monitoring to optimize the conditions of metabolite synthesis [9,10].…”

Metabolism‐Inspired Electrosynthesis

“…Khera and colleagues demonstrated the ability to dial‐in the desired electrosynthetic oxidation state on two commonly prescribed statins (lipid‐lowering drugs), Lovastatin 52 and Simvastatin 56 (Scheme ) . Using a coupled electrochemical‐mass spectrometry set‐up on a milligram scale, hydroxylated metabolites of both were prepared with comparable conversions to those obtained using CYP BM3 mutants although the isolated yield was not stated.…”

Die Erschließung von Wirkstoffmetaboliten durch übergangsmetallkatalysierte C‐H‐Oxidation: die Leber als Inspiration für die Synthese

“…Das EC/MS‐System, ausgerüstet mit einer Bor‐dotierten Diamantelektrode bei einem konstanten Potential von 1500 mV, wurde zur Oxidation von Lovastatin ( 177 , lipidsenkend) in einem Maßstab von weniger als 1 mg verwendet, die zu 3′α‐Hydroxy‐, 6′β‐Hydroxy‐ und 3’α‐5’β‐Dihydrodiol‐Lovastatin‐Analoga ( 178 , 179 , 180 ) führte. Die Ausbeuten waren mit denen vergleichbar, die mit CYP‐BM3‐Mutanten erzielt wurden; drei Metabolite wurden isoliert und NMR‐spektroskopisch charakterisiert.…”