The Study of the Differential-Pulse Voltammetric Behavior of Ergot Alkaloids and Their Determination by Dc Amperometric Detection in a Fia System

Journal of Pharmaceutical & Biomedical Analysis
Vol. I 1, No. 3, pp. 191-196, 1993 Printed in Great Britain

0731-7085/93 $6.00 + 0.00 ~) 1993 Pergamon Press Ltd

The study of the differential pulse voltammetric behaviour of ergot alkaloids and their determination by DC amperometric detection in a FIA system*
JUDIT INCZEFFY,t$ ZSUZSA BERTHA SOMODI,$ ZSOFIA PAP-SZIKLAY$ and GYORGY FARSANG§
$ Chemical Works of Gedeon Richter Ltd, P.O.B. 27, H-1475 Budapest, Hungary § Institute of Inorganic and Analytical Chemistry of L. EOtvOs University, P. O.B. 32, H-1518 Budapest, Hungary
Abstract: 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.

Keywords: Electrochemical oxidation; ergot alkaloids; differential pulse voltammetry; DC voltammetry; controlled potential

References: [1] R.H.F. Manske (Ed.), Vol. 15, The Alkaloids, Chap. 1, pp. 1-36. Academic Press, New York (1975). [2] J. Wang and M. Ozsoz, Electroanalysis 2, 595-599 (1990). [3] F. Belal and J.L. Anderson, Talanta 33, 448-450 (1986). [4] G. Szepesi, M. Gazdag and L. Terdy, J. Chromatogr. 191, 101-108 (1980). [5] L. Szepesy, I. Feh6r, G. Szepesi and M. Gazdag, J. Chromatogr. 149,271-280 (1978). [6] G. Szepesi, J. Molnfir and Sz. Nyiredy, Z. Anal. Chem. 294, 47-48 (1979). [7] G. Szepesi and M. Gazdag, J. Chromatogr. 122, 479485 (1976). [8] P. Horvfith, G. Szepesi and A. Kassai, Planta Med. 33, 407-4ll (1978). [9] S. Pap-Sziklay, E. M~irton-Puzsfir, Zs. Bertha-Somodi and I. P6ter, Magyar K(miai Foly6frat 93, 171-176 (in Hungarian) (1987). [Received for review 5 June 1992; revised manuscript received 18 September 1992] m e a s u r e d for the concentration level corresponding to the 100% ergotamine tartrate content o f the c o a t e d tablet. T h e R S D was 1.9%. In Fig. 4 10 F I A a m p e r o m e t r i c signals are shown; these were r e c o r d e d after the injection of solutions each p r e p a r e d f r o m individual tablets. Conclusions A rapid, selective and accurate m e t h o d based on voltammetric detection in a PCcontrolled a u t o m a t e d F I A system w a s develo p e d for the determination of ergot alkaloids in solid dosage forms. This m e t h o d can be used