Relative bioavailability of salbutamol to the lung following inhalation via a novel dry powder inhaler and a standard metered dose inhaler |
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Authors: | M. Hindle,E. M. Peers,M. Parry-Billings,& H. Chrystyn |
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Affiliation: | Innovata Biomed Ltd, St Albans, UK |
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Abstract: | Aims The number of dry powder inhaler (DPI) devices could increase because they are easier to use than a metered dose inhaler (MDI). Using urinary excretion, the relative bioavailability of salbutamol to the lungs and the body for a prototype DPI has been compared with an MDI. Methods A randomized, double-blind, two way crossover study compared the amount of salbutamol in the urine 30 min following inhalation of 2×100 μg salbutamol from a prototype DPI (Innovata Biomed Ltd, UK) and a Ventolin® (Allen and Hanburys Ltd, UK) MDI in 10 volunteers. The amount of salbutamol and its metabolite, the ester sulphate conjugate, renally excreted up to 24 h post inhalation was also determined to evaluate the relative bioavailability of salbutamol to the body. Results The mean (s.d.) 30 min post-treatment urinary excretion for the prototype DPI and MDI was 8.4 (2.6) and 5.0 (1.9) μg, respectively ( P <0.001). The total amount of salbutamol and its ester metabolite excreted in the urine over the 24 h period after inhalation was 187.9 (77.6) and 137.6 (40.0) μg ( P <0.05). Conclusions The prototype DPI delivered more salbutamol to the body and the lungs than a conventional MDI. This finding supports further development of the prototype DPI. The urinary salbutamol method is able to discriminate between two different inhalation systems. |
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Keywords: | salbutamol dry powder inhaler metred dose inhaler |
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