Salting-out thin-layer chromatography of some angiotensin converting enzyme inhibitors on different sorbents

Chromatographic behaviour of six anti hypertensive drugs from the class of ACE inhibitors was studied under conditions of salting-out thin-layer chromatography on silica-gel, cellulose and polyacrylonitrile (PANS) as sorbents. For this purpose, different concentrations of aqueous ammonium sulphate solutions were used as solvents. In all cases studied, it was established that hR(F) values decrease with increasing salt concentrations in the chromatographic solvent Systems used. In addition, a linear relationship of the corresponding R-M values and ammonium sulphate content in the solvent was observed. To explain these results, a separation mechanism based on hydrophobic interaction between the sorbend and sorbent is proposed.