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Canadian researchers have used ultraviolet spectroscopy to validate the efficacy of a new dry powder inhaler developed by their laboratory. Biljana Grgic, Zhaolin Wang, and Warren Finlay founder of the Aerosol research Laboratory of Alberta, in the Department of Mechanical Engineering, at the University of Alberta, in Edmonton, have developed a new type of dry powder inhaler (DPI) for drug delivery that is not only compact and highly efficient but reduces the deposits of powder that cause throat problems for many patients using conventional inhalers, such as asthma sufferers. The most important function of an inhaler is to ensure that the drug is delivered as deep into the lung as possible. DPIs help in this endeavour by being breath activated so that patients are not required to coordinate pressing the trigger and breathing in at the same time as they are with metered dose inhalers. Despite the ongoing efforts of laboratories around the world, including ARLA, the way IPAs actually work remains unclear because of the complicated manner in which aerosol is dispersed on patient triggering of the device and inhalation. ARLA and the other laboratories hope to improve understanding of IPA action and so develop new more effective devices that waste less drug and provide greater benefits for patients using inhaled pharmaceutical aerosols. To test the performance of their DPI the researchers measured total aerosol deposition in and around a model mouth-throat cast. They also determined the fraction of fine particles produced using a standard Mark II Anderson impactor. In addition, ultraviolet spectroscopy was used to assess the chemistry of the aerosol deposits. The team tested their DPI using a common aerosol powder - the commercial corticosteroid budesonide used in asthma prevention and an ARLA preparation of the antibiotic ciprofloxacin containing lipid and lactose. They dispersed both drugs into the mouth-throat model at an inhalation flow rate of 60 litres per minute to simulate ideal inhalation by a patient. The newly developed DPI had an improved total aerosol delivery distal to the mouth-throat model compared with the original Turbuhaler device for delivery of both budesonide and ciprofloxacin + lipid + lactose aerosols. Importantly, mouth-throat deposition fell from around 30% to about 10% with the present inhaler. The researchers explain that the different lung deliveries observed with the same inhaler for two drug formulations also suggests that a DPI can be optimized still further using novel powder formulations. Finlay's DPI was co-invented by Wang, Grigic, and E Matida and will be commercialised by international pharmaceutical company LAB Pharma Inc based in Canada with offices in Europe and the USA. Related links:
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 Finlay, bringing a breath of fresh air to DPI research Budesonide, helping lungs breathe deeper |
