国生一 Dry Powder Inhalers 国生 Dry Powder Inhalers Formulation design of dry powder inhaler Formulation design of dry powder inhaler Low aerodynamic diameters Dry powder particles of suitable size range, Low inter-particulate forces generally considered between I and 6 um,can be readily produced. However,such particles have high surface area to mass ratio,making them highly cohesive/adhesive in nature. 国生一 图上生 图Carrier 图Carrier To overcome agglomerate,coarse carrier is The balance of interparticle forces is very used for the micronized drug. important,because a drug particle needs to be The drug is blended with and distributed over strongly attached to the carrier,yet becomes the surface of the coarse carrier. easily detached on aerosolisation to form a fine particle cloud 国坠生 圈生一 Pre-metered single dose ©Devices ·Spinhaler Pre-metered single dose Pre-metered multidose as single units Multidose bulk reservoir 77 Shanghai Jiao Tong University Dry Powder Inhalers Formulation design of dry powder inhaler • Low aerodynamic diameters • Low inter-particulate forces Shanghai Jiao Tong University Dry Powder Inhalers Formulation design of dry powder inhaler • Dry powder particles of suitable size range, generally considered between 1 and 6 μm, can be readily produced. • However, such particles have high surface area to mass ratio, making them highly cohesive/adhesive in nature. Shanghai Jiao Tong University Carrier • To overcome agglomerate, coarse carrier is used for the micronized drug. • The drug is blended with and distributed over the surface of the coarse carrier. Shanghai Jiao Tong University Carrier • The balance of interparticle forces is very important, because a drug particle needs to be strongly attached to the carrier, yet becomes easily detached on aerosolisation to form a fine particle cloud Shanghai Jiao Tong University Devices • Pre-metered single dose • Pre-metered multidose as single units • Multidose bulk reservoir Shanghai Jiao Tong University Pre-metered single dose • Spinhaler