Temperature controlled ionic liquid aqueous two phase system combined with affinity capillary electrophoresis for rapid and precise pharmaceutical-protein binding measurements

Publication date: Available online 10 February 2018 Source:Methods Author(s): Deia Abd El-Hady, Hassan M. Albishri Temperature controlled ionic liquid aqueous two phase system (ILATPS) was used to improve the precision of pharmaceutical-AGP (human alpha (α1)-acid glycoprotein) binding measurements by affinity capillary electrophoresis (ACE). The effect of different types of short-chain alkyl imidazolium ILs within the concentration range of 10.0–1000.0 μmol L-1 on a propranolol (PRO)-AGP model was firstly investigated by ILATPS/ACE system. Use of 100.0 μmol L-1 1-butyl-3-methylimidazolium chloride (BMImCl) in 67.0 mmol L-1 potassium phosphate buffer (pH 7.4) containing low concentrations of AGP (5.0-100.0 µmol L-1) gave the highest precision value (2.98±0.14×105 L/mol) which is in concord with the reported one (3.00×105) under similar experimental conditions. The proposed BMImCl/phosphate solution was a unique temperature controlled system to preserve AGP activity during the pre-analysis and within ACE measurements under lab conditions for about 30 days. This period could be prolonged by converting the one-phase solution into biphasic solution at 4 °C storage temperature and again it could get rapidly back into one-phase by raising the temperature with gentle shaking. This behavior could be attributed to the electrostatic interaction and π- π interaction between BMIm cations and negatively charged AGP ions (pI= 2.7). Moreover, the compatibility of ILATPS with ...
Source: Methods - Category: Molecular Biology Source Type: research