VOLUMATIC USAGE - SOME GENERIC SALBUTAMOL METERED-DOSE INHALERS CAN BE USED

Background - The 30 minute and 24 hour post-inhalation urinary excretion of salbutamol represents the relative amount of drug deposited in the lungs and total systemic absorption, respectively. Using this method two metered dose inhalers used with a Volumatic (Alien and Hanburys Ltd, UK) large volume spacer have been compared. Method - Eleven healthy volunteers inhaled 4 x 100 mu g salbutamol from either a generic salbutamol (Baker Norton, UK) or Ventolin (Allen and Hanburys Ltd, UK) metered dose inhaler with a Volumatic. The order of administration was randomised with a seven day washout period. Urine samples were collected for 0-30 minutes and then pooled up to 24 hours after inhalation. Results - The mean (SD) urinary salbutamol excretion 30 minutes after inhalation with the metered dose inhalers used with the Volumatic was 22.22 (4.63) and 21.30 (5.91) mu g for the Baker Norton and Ventolin respectively, with a mean difference (95% confidence interval (CI)) of 0.92 (-0.65 to 2.49) mu g. Similar amounts were excreted up to 24 hours after the dose with a mean (SD) urinary excretion of 116.1 (24.3) mu g and 114.8 (22.3) mu g, respectively, and a mean difference (95% CI) of 1.22 (-20.39 to 22.84) mu g. Conclusion - Inhalations from generic salbutamol (Baker Norton) and Ventolin metered dose inhalers with a Volumatic inhalation aid deliver similar amounts of drug to the lungs and the total systemic absorption from the two products is the same.