The study of the differential pulse voltammetric behaviour of ergot alkaloids and their determination by DC amperometric detection in a FIA system.

The ergot alkaloids possess strong pharmacological effects and are important drugs with widespread clinical uses. The ergot alkaloid preparations manufactured by Gedeon Richter Chemical Works Ltd have a very low active substance content (e.g. 1.0 mg in each Secadol (0.4 g) coated tablet); therefore a sensitive method of determination must be used. Because of this constraint the differential pulse voltammetric behaviour of ergot alkaloids was studied in respect of the effects of pH and composition of media and an automated FIA system with amperometric detection has been used to develop a selective and sensitive method for the routine quantitative assay of these alkaloids. A short summary is given of the experimental evidence to substantiate the stoichiometric equation proposed for the electrochemical oxidation of the lysergic acid type of ergot alkaloids, the mechanism may be generally applicable for compounds having the ergoloid skeleton. In the course of the work it was concluded that a simple DC amperometric method of detection in a FIA system could be applied to determine the content of ergot alkaloids of different pharmaceutical preparations. A suitable method designed to meet current analytical requirements has been developed and validated.

Use of overpressurized thin-layer chromatography (OPTLC) for the separation of amino-acids and polypeptides.

Overpressurized thin-layer chromatography (OPTLC) has been used for the separation of amino-acids and polypeptides. The effects of the ratio of pyridine to acetic acid as well as that of butanol to water on the selectivity and efficiency of separation have been investigated in detail. The influence of the nature of organic solvents in the eluent has also been studied. The optimal conditions have been elaborated and the practical applicability in pharmaceutical analysis of the separation system has been demonstrated.