Details for Patent: 7,744,855

Title:	Method of making particles for use in a pharmaceutical composition
Abstract:	A method for making composite excipient particles for use in a pharmaceutical composition comprises a milling step in which particles of an excipient material are milled in the presence of an additive material. The product particles are of small size and the milling requires relatively low input of time and energy. The composite particles are suitable for use in inhalable pharmaceutical compositions.
Inventor(s):	Staniforth; John Nicholas (Bath, GB), Morton; David Alexander Vodden (Bath, GB), Musa; Rosella (Parma, IT)
Assignee:	Vectura Limited (Wiltshire, GB)
Filing Date:	Jun 27, 2001
Application Number:	10/312,488
Claims:	1. A method for making composite excipient particles for use in a pharmaceutical composition, the method comprising a milling step in which particles of an excipient material are milled in the presence of an additive material prior to adding active ingredient, wherein the milling step applies a force sufficient to break coarse excipient particles of mass median aerodynamic diameter (MMAD) greater than 100 .mu.m down to fine particles of MMAD not more than 50 .mu.m and involves mechanofusion, ultracentrifugal milling, jet milling, homogenisation, bead milling, media milling, hybridization, air jet milling, pin milling, hammer milling or knife milling; wherein the milling step results in the additive material being applied to the surfaces of the excipient particles; and wherein the composite particles comprise not more than 60% additive material by weight. 2. A method as claimed in claim 1, in which the mass median aerodynamic diameter of the particles of excipient material is substantially reduced during the milling step. 3. A method as claimed in claim 2, in which the mass median aerodynamic diameter (MMAD) of the particles of excipient material is reduced by at least 50% during the milling step. 4. A method as claimed in claim 1, in which the milling step is carried out in the presence of a fluid. 5. A method as claimed in claim 4, which also comprises the step of removing the fluid after the milling step. 6. A method as claimed in claim 5, in which the fluid is removed by spray drying. 7. A method according to claim 1, which comprises, after the milling step, an agglomeration step in which the composite excipient particles are agglomerated to form agglomerated particles. 8. A method as claimed in claim 7, in which the agglomeration step is a spray drying step. 9. A method as claimed in claim 1, wherein the excipient material is a crystalline sugar. 10. A method as claimed in claim 1, in which the additive material comprises an amino acid. 11. A method as claimed in claim 1, in which the additive material comprises a phospholipid. 12. A method as claimed in claim 1, in which the additive material comprises a metal stearate. 13. Composite excipient particles for use in a pharmaceutical composition as made by the method of claim 1. 14. Composite excipient particles as claimed in claim 13, the composite excipient particles having a mass median aerodynamic diameter of less than 20 .mu.m. 15. A pharmaceutical composition comprising composite excipient particles as made by a method as claimed in claim 1 and active particles. 16. A pharmaceutical composition as claimed in claim 15, which is a dry powder and is suitable for use in a dry powder inhaler. 17. A pharmaceutical composition as claimed in claim 16, which comprises carrier particles. 18. A pharmaceutical composition as claimed in claim 17, which comprises the composite excipient particles in an amount of 1 to 40% based on the weight of the carrier particles. 19. A pharmaceutical composition as claimed in claim 17, in which the carrier particles have a fissured surface. 20. A pharmaceutical composition as claimed in claim 17, in which the carrier particles are of a crystalline sugar having a tapped density not exceeding 0.75 g/cm.sup.3. 21. A pharmaceutical composition as claimed in claim 17, in which the carrier particles have a bulk density as measured by mercury intrusion porosimetry of not exceeding 0.6 g/cm.sup.3. 22. A pharmaceutical composition as claimed in claim 17, in which the carrier particles have a mass median aerodynamic diameter of at least 175 .mu.m. 23. A pharmaceutical composition as claimed in claim 15, which comprises a propellant and is suitable for use in a pressurised metered dose inhaler. 24. A dry powder for use in a dry powder inhaler comprising active particles, carrier particles for carrying the active particles and composite excipient particles as made by the method as claimed in claim 1, each of the composite excipient particles comprising a particle of excipient material having additive material on the surfaces of that particle of excipient material, the additive material being suitable for the promotion of the release of the active particles from the carrier particles on actuation of the inhaler. 25. A pharmaceutical composition comprising composite excipient particles as claimed in claim 14 and active particles. 26. A dry powder for use in a dry powder inhaler comprising active particles, carrier particles for carrying the active particles and composite excipient particles as claimed in claim 14, each of the composite excipient particles comprising a particle of excipient material having additive material on the surfaces of that particle of excipient material, the additive material being suitable for the promotion of the release of the active particles from the carrier particles on actuation of the inhaler. 27. The method of claim 1, wherein said particles have a fissured surface. 28. The method of claim 14, wherein said particles have a fissured surface 29. The method of claim 24, wherein said particles have a fissured surface. 30. The method of claim 29, wherein said particles have a fissured surface. 31. The method of claim 30, wherein said particles have a fissured surface.