Using Laser Diffraction As A Screening Tool For Dry Powder Inhaler Formulations

摘要

Reproducible drug delivery from dry powder inhaler systems requires control of the delivered drug particle size. Particle morphology is also important as the surface properties of the drug and excipient particles can have a significant effect on the process of deagglomeration that occur within the powder spray plume during inhalation. This, in turn, can define the deposition characteristics of the drug within the respiratory tract. Traditionally, particle size analysis of dry powder inhaler formulations has been carried out using cascade impaction (CI). However, CI measurements are time consuming, of low resolution and only provide a time-averaged result. In this work a method is presented for measuring the particle size produced by different dry powder formations using the technique of laser diffraction. Rapid data acquisition speeds of up to are possible using laser diffraction, allowing the dynamics of power release to be assessed along with the average particle size. This can aid in understanding the delivery dynamics and can allow different formulations to be rapidly screened for the correct dispersion properties.