Details for Patent: 6,153,224

Title:	Carrier particles for use in dry powder inhalers
Abstract:	A powder for use in a dry powder inhaler includes active particles and carrier particles for carrying the active particles. The powder further includes additive material (4) on the surfaces of the carrier particles to promote the release of the active particles from the carrier particles on actuation of the inhaler. The powder is such that the active particles are not liable to be released from the carrier particles before actuation of the inhaler. The inclusion of additive material (4) in the powder has been found to give an increased respirable fraction of the active material.
Inventor(s):	Staniforth; John Nicholas (Bath, GB)
Assignee:	Co-ordinated Drug Development Limited (London, GB)
Filing Date:	Sep 25, 1997
Application Number:	08/875,391
Claims:	1. A powder for use in a dry powder inhaler, the powder comprising active particles and carrier particles for carrying the active particles, the powder further comprising additive material on the surfaces of the carrier particles to promote the release of the active particles from the carrier particles on actuation of the inhaler, the powder comprising not more than 10% by weight of additive material based on the weight of the powder and the additive material comprising an amino acid. 2. A powder according to claim 1, wherein the amino acid is leucine. 3. A powder according to claim 1, wherein the powder comprises not more than 4% by weight of additive material based on the weight of the powder. 4. A powder according to claim 3, wherein the powder comprises not more than 2% by weight of additive material based on the weight of the powder. 5. A powder according to claim 1, wherein the additive material is in the form of particles, the additive particles being attached to the surfaces of the carrier particles. 6. A powder for use in a dry powder inhaler, the powder comprising active particles and carrier particles for carrying the active particles, the powder further comprising additive material on the surfaces of the carrier particles to promote the release of the active particles from the carrier particles on actuation of the inhaler, wherein substantially all (by weight) of the carrier particles have a diameter which lies between 20 .mu. and 1000 .mu. and 95% of the additive material is in the form of particles having a diameter of less than 150 .mu., the powder being such that the active particles are not liable to be released from the carrier particles before actuation of the inhaler. 7. A powder according to claim 6, wherein the powder comprises not more than 5% by weight of additive material based on the weight of the powder. 8. A powder according to claim 7, wherein the powder comprises not more than 2% by weight of additive material based on the weight of the powder. 9. A powder according to claim 6, wherein the carrier particles are comprised of one or more crystalline sugars. 10. A powder according to claim 9, wherein the carrier particles are particles of lactose. 11. A powder according to claim 6, wherein substantially all (by weight) of the carrier particles have a diameter which lies between 20 .mu.m and 1000 .mu.m. 12. A powder according to claim 6, wherein the additive material consists of physiologically acceptable material. 13. A powder according to claim 6, wherein the additive material comprises one or more compounds selected from amino acids and derivatives thereof, and peptides and polypeptides having a molecular weight from 0.25 to 1000 KDa, and derivatives thereof. 14. A powder according to claim 7, wherein the additive material comprises an amino acid. 15. A powder according to claim 14, wherein the additive material consists substantially of leucine. 16. A powder according to claim 6, wherein the additive material comprises one or more water soluble materials. 17. A powder according to claim 6, wherein the additive material is in the form of particles, the additive particles being attached to the surfaces of the carrier particles. 18. A powder according to claim 17, wherein at least 95% by weight of the additive particles have a diameter less than 100 .mu.m. 19. A powder according to claim 18, wherein the mass median diameter of the additive particles is not more than about 10 .mu.m. 20. A powder according to claim 6, wherein the powder consists of not loss than 0.1% by weight of additive particles based on the weight of the carrier particles. 21. A powder according to claim 6, wherein the additive material forms a discontinuous covering on the surfaces of the carrier particles. 22. A powder according to claim 20, wherein the additive material, whilst forming a discontinuous covering on the surfaces of the carrier particles, saturates the surfaces of the carrier particles. 23. A powder according to claim 6, wherein the mass median diameter of the active particles is not more than 10 .mu.m. 24. A powder according to claim 6, wherein the active particles comprise a .beta..sub.2 -agonist. 25. A powder according to claim 24, wherein the active particles comprise salbutamol, a salt of salbutamol or a combination thereof. 26. A powder according to claim 6, wherein the active particles comprise beclomethasone dipropionate. 27. Particles for use in a powder according to claim 6, the particles comprising carrier particles in a first composition and of a size suitable for use in a dry powder inhaler and additive material of a second composition, at least some of the additive material being attached to the surface of the carrier particle. 28. A powder for use in a dry powder inhaler, the powder comprising active particles and carrier particles for carrying the active particles wherein the powder further includes additive material which is attached to the surface of the carrier particles to promote the release of the active particles from the carrier particles, the powder comprising not more than 10% by weight of additive material based on the weight of the powder. 29. A method of promoting the release of active particles from the surfaces of carrier particles during inhalation, comprising attaching an additive material to the surfaces of carrier particles suitable for carrying active particles in a powder for use in a dry powder inhaler, and introducing a powder comprising said carrier particles with the additive material and active particles into a dry powder inhaler, 95% of the additive material being in the form of particles having a diameter which of less than 150.mu., substantially all (by weight) of the carrier particles having a diameter which lies between 20.mu. and 1000.mu. and the powder being such that the active particles are not liable to be released from the carrier particles before actuation of the inhaler. 30. A powder for use in a dry powder inhaler where in the powder is made according to a method comprising steps of: (a) mixing carrier particles of a size suitable for use in dry powder inhaler with an amount of additive material such that the additive material becomes attached to the surfaces of the carrier particles, and comprises not more than 10% by weight of additive material based on the weight of the powder; (b) treating the carrier particles to dislodge small grains from the surfaces of the carrier particles, without substantially changing the size of the carrier particles during treatment; and (c) mixing the treated particles with active particles such that active particles adhere to the surfaces of the carrier particles and/or the additive material.