Inhalation performance of pollen-shape carrier in dry powder formulation with different drug mixing ratios: comparison with lactose carrier.

In this study, the drug delivery performance of pollen-shape hydroxyapatite (HA) carriers is assessed and compared with conventional lactose (LA) carriers. Budesonide (Bd) is used as the model drug. Three drug mixing ratios of 2:1, 10:1 and 45:1 (carrier:drug, w/w) are used. The attachment of the drug with the carrier is characterized by sieving test. It is found that the drug content in the blends with HA particles is higher than the blends with LA. In vitro inhalation experiments are also conducted in an Andersen cascade impactor (ACI) equipped with a Rotahaler at gas flow rates of 30 and 60 L/min. The HA blends show high emitted dose (ED) of 82-90% at 30 L/min while the LA blends are observed to have ED of 69-82% at the same conditions. The high emission of the HA blends also allows high fine particle fraction (FPF) of 10-18% while the FPF of the LA blends are 3-15%. At a gas flow rate of 60 L/min, all the HA and LA blends show compatible ED (83-95% for HA blends and 82-84% for LA blends) and FPF (19-41% for HA blends and 21-34% for LA blends). Copyright 2009 Elsevier B.V. All rights reserved.