Spray drying process control of drying kinetics
View Patent ↗The present invention provides exemplary systems and methods for producing dry powder formulations. In one embodiment, a system ( 10 ) includes at least one conditioning zone ( 12 ) having an inlet ( 20 ) to introduce an atomized formulation ( 18 ) into the conditioning zone. A controller ( 14, 16 ) controls temperature and relative humidity of the airflow into the conditioning zone to allow amorphous-to-crystalline transformation of the atomized formulation. In another embodiment, the formulation is suspended in the conditioning zone for a residence time of sufficient duration to allow surface orientation of surface active components. A dryer ( 24 ) is coupled to the conditioning zone to dry the atomized formulation, and a collector ( 28 ) collects the formulation in powder form.
1. A method for producing a powdered formulation, comprising:
introducing an atomized formulation into a conditioning zone from an atomizer;
separately introducing humid air into the conditioning zone from a humid air inlet configured to control a relative humidity range within the conditioning zone;
controlling a first temperature range and the relative humidity range within the conditioning zone for a conditioning time sufficient to promote a crystalline state of a partially dried atomized formulation, wherein the first temperature range is from about 25° C. to about 50° C. and the relative humidity range is from about 10% to about 100%; transferring the partially dried atomized formulation into a second conditioning zone;
introducing the partially dried atomized formulation into a drying zone;
drying the partially dried atomized formulation to form crystallized dry particles within the drying zone; and
collecting the crystallized dry particles of the powdered formulation, wherein the crystallized dry particles have a size within a range from about 0.5 microns MMD to about 10 microns MMD.
2. The method as in claim 1 , wherein the crystallized dry particles have a size within a range from about 1 micron MMD to about 5 microns MMD.
3. The method as in claim 1 , further comprising introducing a cosolvent into the conditioning zone prior to introducing the atomized formulation.
4. The method as in claim 3 , wherein the cosolvent comprises ethanol.
5. The method as in claim 1 , wherein the powdered formulation comprises an active agent.
6. The method as in claim 1 , wherein the powdered formulation comprises an excipient.
7. The method as in claim 1 , further comprising introducing one or more reagents into the second conditioning zone.
8. The method as in claim 1 , further comprising introducing a sublimed material into the second conditioning zone.
9. The method as in claim 1 , further comprising introducing organic vapors or reactants into the second conditioning zone to condition or coat particle surfaces of the partially dried atomized formulation.
10. The method as in claim 1 , wherein the conditioning zone is operated at an elevated pressure.
11. The method of claim 10 , wherein the elevated pressure is up to about 10 atmospheres.
12. The method as in claim 1 , wherein the drying zone is operated at an elevated pressure.
13. The method according to claim 12 , wherein the elevated pressure is up to about 10 atmospheres.
14. The method of claim 1 , wherein the drying comprises introducing heated gas into the drying zone.
15. A method for producing a crystallized powdered formulation, comprising:
introducing an atomized formulation into a conditioning zone from an atomizer;
separately introducing humid air into the conditioning zone from a humid air inlet configured to control a relative humidity range within the conditioning zone;
controlling a first temperature range and relative humidity range within the conditioning zone for a conditioning time sufficient to promote a crystalline state of a partially dried atomized formulation; transferring the partially dried atomized formulation into a second conditioning zone;
introducing the partially dried atomized formulation into a drying zone;
controlling a second temperature range within the drying zone to form crystallized dry particles from the partially dried atomized formulation; and
collecting the crystallized dry particles as a powdered formulation, wherein the crystallized dry particles have a size within a range from about 0.5 microns MMD to about 10 microns MMD.
16. The method of claim 15 , wherein the crystallized dry particles have a size within a range from about 1 micron MMD to about 5 microns MMD.
17. The method of claim 16 , wherein the conditioning time is within a range from about 2 seconds to about 20 seconds.
18. The method of claim 17 , wherein the relative humidity range is from about 10% to about 100%.
19. The method of claim 18 , wherein the first temperature range is from about 25° C. to about 50° C. and the second temperature range is from about 90° C. to about 180° C.
20. The method of claim 16 , wherein the powdered formulation comprises an active agent.
21. The method of claim 20 , wherein the powdered formulation comprises an excipient.
22. The method of claim 15 , further comprising introducing one or more reagents into the second conditioning zone.
23. The method of claim 15 , further comprising introducing a sublimed material into the second conditioning zone.
24. The method of claim 15 , further comprising introducing organic vapors or reactants into the second conditioning zone to condition or coat the partially dried atomized formulation.
25. The method of claim 15 , wherein the controlling the second temperature range comprises introducing heated gas into the drying zone.