Investigation of the C-1311 glucuronidation: an electrochemical approach

This study was undertaken to investigate the glucuronidation of the compound C-1311 (5-diethylaminoethylamino-8-hydroxyimidazoacridinone – the model anticancer acridine derivative) using electrochemistry/mass spectrometry (EC/MS) as a complementary technique to in vitro (liver microsomes) and in silico approaches.
For the EC/MS experiment the RoxyTM system (Antec Scientific, The Netherlands) equipped with an electrochemical thin-layer ReactorCellTM connected directly to a 6470 Triple Quad LC/MS with an AJS (Agilent Jet Stream) ESI interface (Agilent Technologies, USA) was used. The ReactorCellTM was supplied to a disc glassy carbon working electrode (ϕ =8 mm; A = 0.502 cm2) and a HyREF palladium-hydrogen (Pd/H2) pseudo reference electrode. The upper half of the electrochemical cell block made of a chemically inert and physically resistant polyether ether ketone (PEEK; 30% carbon fiber-reinforced) was employed as a counter electrode.
Generation of C-1311 glucuronides:

Sample: 10 μM C-1311 solution in 10 mM ammonium formate (pH ~ 7.4) and methanol (1:1, v/v) (electrolyte solution)
Conjugation reaction: addition of 100 μM glucuronic acid solution in electrolyte solution after the ReactorCellTM via 100 μL T-piece to conjugate C-1311 and/or phase I metabolites
Flow rate: 20 μL/min
Potential: from 0 to 2500 mV (at 10 mV/s)
Reaction temperature: room temperature

EC/MS made it possible to detect three potential 8-O-glucuronides (predicted by XenoSite Reactivity Predictor) derived from C-1311 (m/z 351) and its derivatives – products of C-1311 side chain degradation (corresponding ions at m/z 278 and m/z 323).