Investigations of an optimal inhaler technique with the use of urinary salbutamol excretion as a measure of relative bioavailability to the lung. Issue 6 (June 1993)

• Record Type: Journal Article
• Authors: Hindle, M; Newton, D A; Chrystyn, H
• Is Part Of: Thorax. Volume 48:Issue 6(1993)
• Page Start: 607
• Page End: 610
• Publication Date: 1993-06
• Subjects: Chest -- Diseases -- Periodicals; Thorax; Chest -- Diseases; Periodicals; Periodicals; 617.54
• DOI: 10.1136/thx.48.6.607
• Languages: English
• ISSNs: 0040-6376

Abstract

Abstract : BACKGROUND--A simple non-invasive method, in which a urine sample is taken 30 minutes after drug administration, has previously been shown to be a measure of the relative bioavailability of salbutamol to the lungs. This technique has been used to determine an optimal inhaler technique with commercially available metered dose inhalers (MDI). METHODS--Ten healthy subjects were trained in the use of MDIs. Each inhaled 4 x 100 micrograms salbutamol in a series of experiments to examine the relative bioavailability to the lung after different respiratory manoeuvres. Urine collection intervals were 0-0.5 hours and 0.5-24 hours after administration. RESULTS--There was significantly greater elimination of unchanged salbutamol 30 minutes after administration, indicating a greater relative bioavailability of salbutamol to the lungs after (1) exhaling gently to residual volume rather than to functional residual capacity before inhalation; (2) slow inhalation (10 l/min) compared with fast inhalation (50 l/min); (3) breath holding for 10 seconds after inhalation compared with no breath holding. CONCLUSIONS--All patient information leaflets and healthcare personnel should standardise the instructions given to patients and should adopt the inhalation method proposed.