Optimization of nucleation and crystallization for lyophilization using gap freezing
View Patent ↗This application discloses devices, articles, and methods useful for producing lyophilized cakes of solutes. The devices and articles provide for a method of freezing liquid solutions of the solute by the top and the bottom of the solution simultaneously. The as frozen solution then provides a lyophilized cake of the solutes with large and uniform pores.
1. An article adapted for use in a lyophilization chamber comprising:
a heat sink comprising a heat sink surface in thermal communication with a refrigerant;
a tray comprising a tray surface;
a thermal conduction insulator disposed between the heat sink surface and the tray surface; and
a spacer disposed between the heat sink surface and the tray surface and supporting the tray;
wherein the heat sink surface and tray surface are separated by a fixed distance greater than 1 mm.
2. The article of claim 1 , wherein the heat sink comprises a refrigerant conduit in thermal communication with the heat sink surface.
3. The article of claim 2 , wherein the heat sink further comprises a heat sink medium disposed between the refrigerant conduit and the heat sink surface.
4. The article of claim 1 , wherein the heat sink surface and tray surface are separated by a fixed distance of greater than 1.5 mm.
5. The article of claim 4 , wherein the heat sink surface and tray surface are separated by a fixed distance of greater than 2 mm.
6. The article of claim 5 , wherein the heat sink surface and tray surface are separated by a fixed distance of greater than 2.5 mm.
7. The article of claim 6 , wherein the heat sink surface and tray surface are separated by a fixed distance of greater than 3 mm.
8. The article of claim 7 , wherein the heat sink surface and tray surface are separated by a fixed distance of greater than 4 mm.
9. The article of claim 1 , wherein the heat sink surface and tray surface are separated by a fixed distance 20 mm or less.
10. The article of claim 9 , wherein the heat sink surface and tray surface are separated by a fixed distance 10 mm or less.
11. The article of claim 1 , wherein the spacer has a thickness of greater than 1 mm.
12. The article of claim 11 , wherein the spacer has a thickness of greater than 2 mm.
13. The article of claim 12 , wherein the spacer has a thickness of greater than 3 mm.
14. The article of claim 1 , wherein the spacer has a thickness in a range of 2 mm to 8 mm.
15. The article of claim 1 , wherein the spacer has a thickness in a range of 3 mm to 7 mm.
16. In a method of freezing a liquid solution for subsequent lyophilization, the liquid comprising top and bottom surfaces and disposed in a container, and the container disposed in a lyophilization chamber comprising a heat sink, the improvement comprising separating the container from direct contact with the heat sink during freezing to thereby freeze the solution from the top and bottom surfaces at approximately the same rate.
17. A sample container comprising
a vial comprising top and a bottom; and
a thermally insulating support affixed to the bottom of the vial, the thermally insulating support having a thermal conductivity less than about 0.2 W/m·K at 25° C.
18. The vial of claim 17 , wherein the vial and the insulating support comprise different materials from each other.