Use of reference substances in pharmacopoeia specifications

The use of reference substances in pharmacopoeial specifications has increased enormously during the last decade. In many cases the specification printed in a pharmacopoeia is worthless unless it is supported by a reference substance whose authenticity and integrity has been established beyond doubt and which is maintained and distributed in a satisfactory manner. The types of test procedure for which reference substances might be considered necessary will be reviewed and the criteria which such substances should be required to meet will be considered. Problems associated with the establishment, maintenance and distribution of reference substances for pharmacopoeial purposes will also be reviewed and the need for greater international collaboration in this field will be stressed.