pMDI Uniformity of Delivered Dose Method Development using an Automated Dose Collection Apparatus

Jim Clay & Andy Cooper

3M Drug Delivery Systems Ltd, Loughborough, Leicestershire LE11 1EP

Summary

The analytical methodology for uniformity of delivered dose (UoDD) and dose content uniformity (DCU) is sensitive to user-operation variability associated with the shaking and actuation process of pressurised metered dose inhalers (pMDIs) ^[1]. The analytical method therefore requires control of these parameters for the priming, dose collection and waste actuations and it is the parameters for priming and dose collection that have been assessed, by use of automation.

All data were generated by the use of UV Spectrophotometer methodology or HPLC-UV (High Performance Liquid Chromatography – Ultra Violet detection) methodology.

The data demonstrate that an automated dose collection apparatus (Vertus from Novi Systems Ltd.) can be used to understand user-operation variability associated with the pMDI shaking and actuation process.  This is useful for product development – pMDI devices could be improved by minimising the effect of these parameters, by design. For example, the 3M™ Intelligent Control Inhaler will have no user-operation variability associated with the pMDI actuation process.

It is shown that it is advantageous to use automation for such experiments; they are less subject to sources of variability linked to user operation which may be useful for optimisation studies during method development. Finally, it was demonstrated that the Vertus can be used for routine product analysis – The data for three different suspension products were very accurate and precise in terms of theoretical ex-actuator dose.