The PreciseInhale system works as an exposure platform where different means of aerosol generation in combination with equipment for controlled dosing enables its use in a wide range of exposure modules for application in in vitro and in vivo animal studies.
To characterize the pharmaceutical performance of PreciseInhale with respect to dose uniformity and accuracy, micronised budesonide was used. Aliquots of drug substance were aerosolised and the resulting aerosol was subsequently withdrawn using low, clinically relevant flows (7 and 15 L/min), collected and assayed by UPLC. In parallel, the signal obtained from the in-line Casella particle counter was integrated over the time of dose withdrawal and hereby forming an estimated aerosol dose.
Using the Casella estimated aerosol dose, pre-set target doses could be set. Target doses on several different levels were selected to investigate the uniformity and accuracy of the software dosing procedure.
By using the Casella dosing functionality, significantly improved dose uniformity was achieved. However, the doses delivered were a lot higher than the pre-set target doses, indicating that the control software is not capable of controlling the doses at the flow rates investigated (7 and 15 L/min).
By using the in-line Casella particle counter and hereby estimating and controlling the aerosol dose, good dose uniformity was achieved. But at the patient relevant inhalation flows used, it is evident that the dose accuracy is currently not sufficient. This is important to consider in future use of the PreciseInhale.