A direct correlation was shown between droplet si.ze and granule si ze. Spray characteristics of the atomised granulating solution were measured using a Malvern ST 1800 Particle and Droplet Size Analyser. This was achieved by studying the spray characteristics and droplet size of the atomised granulating solution, and investigating powder bed hydrophobicity. A closer examination of those factors influencing bed wettability was indicated. The variables found to exert a significant effect upon granule quality were those which affected the wetting of the powder mix and rate of evaporation during granulation.

Duringgranule assessment the torque generated by a paddle revolving in a granule mass was shown to be a useful measure of granule quality. Initially the effect of seven process variables upon granule quality was quantified using a factorially designed experiment.

IIДЈ CONTENTS Abstract IV List of Figures V List of Tables VIII CHAPTER 1 INTRODUCTION AND SCOPE OF THESIS 1-35 CHAPTER 2 MATERIALS AND METHODS CHAPTER 3 INVESTIGATION INTO THE INFLUENCE OF PROCESS VARIABLES UPON GRANULE QUALITY CHAPTER 4 SPRAY DROPLET CHARACTERISATION CHAPTER 5 INFLUENCE OF POWDER MIX WETTABILITY UPON GRANULATION CHAPTER 6 AN INVESTIGATION INTO THE GRm-lTH MECHANISM AND STRUCTURE OF GRANULES PREPARED BY FLUIDISED BED GRANULATION CHAPTER 7 OVERALL DISCUSSION AND CONSIDERATIONS FOR FUTURE WORK BIBLIOGRAPHY APPENDICES Al - A20 IIIД¤ STUDIES ON THE FLUIDISED BED GRANULATION PROCESS by MICHAEL BANKS ABSTRACT This study is an evaluation of the process of fluidised bed granulation with the objectives of elucidating the mechanism of granule formation and identifying the fundamental parameters affecting granule quality thereby enabling the true benefits of the process to be realised. Finally my parents and fiancee for their patience and support. For typing services, often under extreme pressure of work: Mrs. The management of Abbott Laboratories, International Division for providing the opportunity to complete this thesis. Felton (Sheffield University) for use of the Malvern ST 1800 droplet size analyser. Smith of Riker Laboratories for use of the instrumented tablet machine. Proudfoot (Leicester School of Pharmacy). Aulton, as internal supervisor for his contribution to the guidance and planning of the project and constant encouragement. In particular I would like to acknowledge the individual participation and encouragement of the following people: Dr. June, 1981Дў ACKNOWLEDGEMENTS I would like to thank most sincerely all my friends and colleagues who have contributed to the completion of this thesis. Submitted in part fulfilment of the requirements for the degree of Doctor of Philosophy. in collaboration with Riker Laboratories, Loughborough. School of Pharmacy, Leicester Polytechnic, Leicester. Thesis Presented to the Council for National Academic Awards for the DEGREE OF DOCTOR OF PHILOSOPHY.

1 STUDIES ON THE FLUIDISED BED GRANULATION PROCESS by Michael Banks, B.Sc.(Hons.) Pharm.

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