Abstract
ABSTRACT
New proposals for the testing of dose delivery from metered-dose inhalers (MDI's) are discussed. Data are presented to show that overdosing may be a problem the first time an inhaler is used. Delivery of amounts of drug in excess of 2-3 times the label claim was observed for the first spray in one product. The problem was less severe for a second product but was still present. Dose delivery problems remain after initial use of the MDI's studied but underdosing was observed. The severity of the problem depends on the product and on a number of factors, including valve orientation during periods of inactivity and whether an unprimed or a primed spray is examined. Testing protocols and requirements that would be appropriate during product development and for quality control are discussed.
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