Lactose fluidisation properties and their relationship to dry powder inhaler performance

Adding lactose fines to a dry powder inhaler (DPI) formulation is hypothesised to increase the tensile strength of the powder thus resulting in higher fluidisation energy and consequentially in improved drug delivery. The aim of the study was to test the hypothesis. The results show that an increase in fluidisation energy corresponds to an improved DPI performance in the case of micronised fines. With milled fines no such clear link between fluidisation energy and DPI performance was seen.