A new and fast DLLME-CE method for the enantioselective analysis of zopiclone and its active metabolite after fungal biotransformation

Author(s)

Perez de Albuquerque, Nayara Cristina ^[1] ; de Gaitani, Cristiane Masetto ^[2] ; Moraes de Oliveira, Anderson Rodrigo ^[1]

Affiliation

^[1] Univ Sao Paulo, Dept Quim, Fac Filosofia Ciencias & Letras Ribeirao Preto, BR-14040901 Ribeirao Preto, SP - Brazil

^[2] Univ Sao Paulo, Dept Ciencias Farmaceut, Fac Ciencias Farmaceut Ribeirao Preto, BR-14040903 Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: Journal of Pharmaceutical and Biomedical Analysis; v. 109, p. 192-201, MAY 10 2015.
• Web of Science Citations: 12

Abstract

Zopiclone (ZO) is a chiral drug that undergoes extensive metabolism to N-desmethylzopiclone (N-Des-ZO) and zopiclone-N-oxide (N-Ox-ZO). Pharmacological studies have shown (S)-N-Des-ZO metabolite presents anxiolytic activity and a patent for this metabolite was requested for anxiety treatment and related disorders. In this context, biotransformation employing fungi may be a promising strategy to obtain N-Des-ZO. To perform the biotransformation study in this work, an enantioselective method based on capillary electrophoresis (CE) and dispersive liquid-liquid microextraction (DLLME) was developed. CE analyses were carried out in sodium phosphate buffer (pH 2.5; 50 mmol L-1) containing 0.5% (w/v) carboxymethyl-beta-CD, at a constant voltage of +25 kV. DLLME was conducted using 2 mL of liquid culture medium pH 9.5. Chloroform (100 mu L) and methanol (300 mu L) were employed as extraction and disperser solvent, respectively. After CE and DLLME optimization, the analytical method was fully validated. The method was linear over a concentration range of 90-6000 ng mL(-1) for each ZO enantiomer (r > 0.999) and 50-1000 ng mL(-1) for each N-Des-ZO enantiomer (r > 0.998). Absolute recovery of 51 and 82% was achieved for N-Des-ZO and ZO, respectively. The accuracy and precision results agreed with the EMA (European Medicines Agency) guideline, and so did the stability study. Application of the developed method in a biotransformation study was conducted in order to investigate the ability of fungi, belonging to the genus Cunninghamella, in metabolizing ZO chiral drug. Fungi Cunninghamella elegans ATCC 10028B and Cunninghamella echinulata var elegans ATCC 8688A demonstrated to be able to enantioselectively biotransform ZO to its active metabolite, N-Des-ZO. Therefore, the proposed goals of this work, Le. a fast DLLME-CE method and an outstanding strategy to obtain N-Des-ZO, were successfully attained. (C) 2015 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 12/21578-8 - Assessment of enantioselective fungal metabolism of zopiclone and analysis by capillary electrophoresis
• Grantee: Nayara Cristina Perez de Albuquerque
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 13/17658-9 - Development and validation of chromatographic and electrophoretic methods for subsequent application in studies of in vitro metabolism and biotransformation - phase 2
• Grantee: Anderson Rodrigo Moraes de Oliveira
• Support Opportunities: Regular Research Grants