Caratterizzazione tecnologica di un nuovo prototipo di inalatore multidose per polveri (MDPI)

Multidose Dry Powder Inhalers (MDPI) appear the best alternative to Metered Dose Inhalers (MDI) which are characterised by several problems mainly due to the CFC world-ban. In this work a new prototype of DPI has been tested in terms of delivery efficiency, precision, uniformity and reproducibility of the emitted dose and respirable fraction, in controlled aerodynamic conditions. Generally, in the case of DPIs, the energy needed for actuation and dose delivery is given by patient's breathing effort, as a consequence, the reduction of the inhalation flow, due to a pulmonary disease, could be a critical factor, influencing the effective delivery of the dose. For this reason, in this study, the efficiency of dose delivery was verified at two different flow rates: 30 and 60 1/min, while the deposition pattern was tested using the Twin Impinger method. The results show that the dose delivered from the prototypes tested is precise and reproducible for all the 100 labelled doses and the device is able to dispense the entire dose at the two flow rates considered. The respirable fraction is about 37% and it remains constant and reproducible during all the life of the inhaler independently of the sequence of actuations. By comparing the performance of the prototypes a good inter-device reproducibility can be evidenced in both emitted dose and respirable fraction.