A Novel Method to Chromatographically Resolution Of Sulphonamides By Vapour-Programmed Thin-Layer Chromatography

Identification, especially of drugs, plays an important role in pharmaceutical analysis. Thin-layer chromatography (TLC) has been widely applied in this field, but sometimes its resolving power leaves something to be desired. Barbiturates, steroids, sulphonamides and local anaesthetics, for example, represent classes where an abundance of closely similar derivatives are available. Separations and identification within these classes are by no means easy to perform. Recently, however, a new type of TLC was developed in our laboratory, namely vapour-programmed TLC (VP-TLC) [1], which allows optimum vapour conditions to be established at the distinct feed tray and, as a consequence, better separations usually result. This technique has already proved to be very satisfactory for the analysis of barbiturates and local anaesthetics and preliminary investigations with a small number of sulphonamides were also very promising [2]. We would now like to report a VP-TLC procedure by which fifteen sulphonamides can be separated and identified.