Lyophilization system and method
View Patent ↗System and method for lyophilization or freeze-drying is provided. During the freezing step, the material or solution to be frozen is initially brought to a temperature near or below its freezing temperature after which the pressure in the freeze-dryer chamber is reduced to induce nucleation of the material.
1. A method of lyophilizing a material within a freeze-dryer chamber comprising the steps of:
pressurizing the gas atmosphere within the freeze-dryer chamber to a pressure level of between about ambient pressure and 25 psi above ambient pressure;
bringing the material to a temperature near or below a phase transition temperature in the pressurized gas atmosphere;
rapidly changing the pressure to nucleate freezing in the material; and
drying the material to produce a dried product having reduced moisture or solvent.
2. The method of lyophilizing as set forth in claim 1 wherein the material is selected from the group consisting of: a biopharmaceutical material, a pharmaceutical material, a biological material, or combinations thereof.
3. The method of lyophilizing as set forth in claim 1 wherein the pressurized gas atmosphere comprises an inert gas.
4. The method of lyophilizing as set forth in claim 1 wherein the pressurized gas atmosphere comprises a gas selected from the group consisting of:
argon, nitrogen, helium, xenon, air, or mixtures thereof.
5. The method of lyophilizing as set forth in claim 1 wherein the material is brought to a temperature ranging from about 0° C. to −10° C. prior to the step of rapidly changing the pressure to nucleate freezing in the material.
6. The method of lyophilizing as set forth in claim 1 wherein the step of rapidly changing the pressure to nucleate freezing in the material further comprises rapidly decreasing the pressure by about 7 psi or more.
7. The method of lyophilizing as set forth in claim 1 wherein the step of rapidly changing the pressure to nucleate freezing in the material further comprises rapidly decreasing the pressure such that an absolute pressure ratio, P i /P f , is about 1.2 or greater.
8. The method of lyophilizing as set forth in claim 1 wherein the step of rapidly changing the pressure to nucleate freezing in the material further comprises rapidly decreasing the pressure at a pressure rate drop, ΔP/Δt, greater than about 0.2 psi per second.
9. The method of lyophilizing as set forth in claim 1 wherein the step of rapidly changing the pressure to nucleate freezing in the material further comprises rapidly decreasing the pressure in 10 seconds or less.