How much aerosol reaches the lungs of wheezy infants and toddlers?

Using sodium cromoglycate as a non-toxic marker, we assessed the delivery of aerosol to nine wheezy infants and seven healthy adults. The drug was delivered to the infants by face mask and spacer device from a metered dose inhaler, and by face mask and nebuliser to the infants and the adults who breathed though their noses. The concentration of sodium cromoglycate was estimated in timed urine collections to find out how much of the dose was absorbed from the lung. Only 0.13% to 0.61% of the 20 mg nominal dose was detected in the urine, representing an estimated 0.3% to 1.5% deposited in the lung. Nasal filtration of aerosol could be a critical factor in reducing lung deposition.