Respimat deposition

S. P. Newman, J. Brown, K. P. Steed, S. J. Reader, and H. Kladders, Lung deposition of fenoterol and flunisolide delivered using a novel device for inhaled medicines Comparison of RESPIMAT with conventional metered-dose inhalers with and without spacer devices, Chest 113 951 (1998). 

Pitcairn, G, Reader, S., Pavia, D., and Newman, S. (2005), Deposition of corticosteroid aerosol in the human lung by respimat soft mist inhaler compared to deposition by metered dose inhaler or by turbuhaler dry powder inhaler, J. Aerosol Med., 18, 264-272. 

Newman examined the deposition profiles in patients of several developmental Respimat prototypes using gamma scintigraphic techniques. In these studies, the deposition of the bronchodilator fenoterol and the corticosteroid flunisolide were examined. Fenoterol in the Respimat was formulated in an aqueous medium, and flunisolide was formulated in 96% ethanol. The experimental data from these studies are shown in Table 12. 

The performance of the Respimat was clearly improved for the flnal prototype compared with Prototype III. Drug deposition in the lungs increased from approximately 31% to 39% for the fenoterol, and from about 40% to 45% for the drug compound of flunisolide respectively. At the same time, the oral-pharyngeal deposition decreased from approximately 54% to 37%... 

Table 12 Average deposition data using the Respimat (% of the emitted dose)...

In scintigraphic studies using fenoterol and flunisolide, mean drug delivery to the lungs was 31-45% of the dose delivered using Respimat compared with less than 20% using a CFC MDI. Safety profiles did not differ between Respimat and CFC MDI administration. Facial deposition data suggested a low risk of untoward effects even in potential misuse situations for Respimat. 

Lung deposition of fenoterol with the use of Respimat, a MDI, and a MDI plus Aerochamber in healthy volunteers was found to be 39, 11 and 10%, respectively. The use of Respimat resulted in uniform deposition of drugs throughout the peripheral, intermediate, and central lung zones. On the other hand, oropharyngeal deposition of fenoterol from Respimat was lower than that from the MDI (37% vs 72%). 

Steed, K. P., L. J. Towse, B. Freund, and S. P. Newman. 1997. Lung and oropharyngeal depositions of fenoterol hydrobromide delivered from the prototype III hand-held multidose Respimat nebuliser. Eur.. Pharmaceut. Sci. 5 55-61. 

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