Lung bioavailability of generic and innovator salbutamol metered dose inhalers.
BACKGROUND
The aim of this study was to determine whether significant differences exist in lung bioavailability between generic (Salamol, Salbulin) and innovator (Ventolin) formulations of inhaled salbutamol given by metered dose inhalers.


METHODS
Ten healthy volunteers of mean age 20.5 years with a forced expiratory volume in one second (FEV1) of 112.1% predicted were studied in a randomised double blind single dosing crossover study. Salbutamol, 1200 micrograms, was given with mouth rinsing and lung bioavailability was assessed by measuring plasma salbutamol levels and urine excretion of salbutamol.


RESULTS
No differences were seen between innovator and generic salbutamol metered dose inhalers in plasma salbutamol levels, urinary salbutamol excretion, or extrapulmonary beta 2 activity. The maximum plasma salbutamol concentration (mean Cmax) and time to maximum concentration (median Tmax) were: Ventolin (2.93 ng/ml, 10 minutes), Salbulin (3.01 ng/ml, 10 minutes), Salamol (3.33 ng/ml, 10 minutes). The geometric mean ratio and 95% confidence interval for Cmax were: Salbulin/Ventolin 1.02 (0.69 to 1.41) and Salamol/Ventolin 1.13 (0.94 to 1.35).


CONCLUSIONS
No differences are apparent between the two generic and innovator formulations of salbutamol metered dose inhaler in terms of lung bioavailability.
Clark
D J
DJ
Department of Clinical Pharmacology, Ninewells Hospital and Medical School, University of Dundee, UK.
Gordon-Smith
J
J
McPhate
G
G
Clark
G
G
Lipworth
B J
BJ
D000328:Adult; D000420:Albuterol / Q000378:metabolism / Q000493:pharmacokinetics* / Q000494:pharmacology; D000704:Analysis of Variance; D001682:Biological Availability; D004311:Double-Blind Method; D016503:Drug Delivery Systems; D006801:Humans; D008168:Lung / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009330:Nebulizers and Vaporizers
D000420:Albuterol