ACKNOWLEDGEMENTS

The authors thank N. de Haan for his skilful technical help during the development of the HPLC-method, Dr. L. Stolk (AZUA-Apotheek, Academic Medical Centre) for the opportunity to use the curve-fitting computer program MW/Pharm and Dr. R.S. Leeuwin for his continuous interest and critical reading of this manuscript.

The authors wish to thank the following contributors to this study: P.J. Geerlings MD, J.G.R. Ufkes PhD, R.S. Leeuwin PhD, P.A.E.G. Delespaul PhD, H.M.B. Leunissen MA.

We thank R.S. Leeuwin Ph.D. for his comments on the manuscript and the CODA (Jellinek Clinic) for their cooperation.

The authors wish to thank V.M. Hendriks and M.W.J. Koeter for their help with analysing the data, as well as H.M.B. Leunissen and C.D. Kaplan for their contribution to this study.

This study was initiated by Prof. Dieter Hellenbrecht MD in 1993/94, who unfortunately deceased october 1994. The authors wish to thank the following persons for their cooperation with this study; Prof. W. van den Brink PhD and R.S. Leeuwin PhD.

The authors wish to thank the following contributors to this study: prof. W. van den Brink Ph.D, H. van Wilgenburg Ph.D, S.P. de Vries MA and R.S. Leeuwin Ph.D.

The authors are indebted to Prof. dr. F.A. de Wolff for his generous gift of pure dextromoramide tartrate for calibration purposes and to Dr. R.S. Leeuwin for his continuous interest and critical reading of this manuscript.