Factors Affecting In Vitro Testing of Inhalers

Abstract

ABSTRACT By examining data for various inhalers under a range of conditions, we have demonstrated the effect of air flow, humidity, and the shape of an artificial throat, on delivery for a number of different inhaler types. The importance of these effects will be discussed by showing how the achievable flow through an inhaler can be estimated, indicating that standard test conditions of 60 1/min flow may be inappropriate for some inhaler types, and may over estimate their performance.