Effect of variable inspiratory flow rate on the performance of the budesonide Rhinocort Turbuhaler (TM)

Objective: To investigate the effect of variable nasal inspiratory flow rat es in vitro on total drug delivery and deposition patterns of budesonide de livered from the Rhinocort Turbuhaler (TM) Methods: The total dose of budesonide delivered at flow rates of 15, 30 and 60 L/min and the particle size distribution of the delivered drug at flow rates of 28 and 60 L/min were determined at regular intervals throughout th e life of six Rhinocort Turbuhalers (TM) each containing 200 x 100 mug dose s of budesonide. The delivered dose was determined by drawing individual do ses of budesonide through separate G0120 Filtrete electrostatic filters. A cascade impactor was used to determine the particle size distribution of th e delivered drug. Results: The amount of budesonide delivered from each Turbuhaler (TM) devic e was variable throughout the life of the devices and was dependent on the inspiratory flow rate. Variability was greatest at the lower flow rates and decreased slightly with increasing inspiratory flow rate. Similarly, the p article size distribution of budesonide throughout the cascade impactor was variable and dependent on the flow rate. dConclusion: This study suggested that the efficiency of the Rhinocort Turb uhaler (TM) device in the management of allergic rhinitis may be influenced by the severity of nasal symptoms, particularly rhinorrhoea and nasal bloc kage, which determine the peak nasal inspiratory flow rates in symptomatic individuals.