Lyophilization of synthetic liposomal pulmonary surfactant

1. A lyophilized synthetic pulmonary surfactant composition comprising:

at least one phospholipid and a synthetic polypeptide having at least 10 amino acid residues and represented by a formula:

(Z a U b ) c Z d

wherein Z represents a hydrophilic amino acid residue and U represents a hydrophobic amino acid residue; wherein each Z is independently R, D, E or K; and each U is independently V, I, L, C, Y, or F; and wherein a is an integer with an average value of about 1 to about 5; b is an integer with an average value of about 3 to about 20; c is an integer of about 1 to about 10; and d is an integer of about 1 to about 3, wherein the lyophilized synthetic pulmonary surfactant composition has a specific surface area at least 2.2 m 2 /g or a porosity above 40% by volume of a total area of the lyophilized synthetic pulmonary surfactant.

2. The lyophilized synthetic pulmonary surfactant of claim 1 , wherein the specific surface area is in the range from about 3.7 m 2 /g to about 2.2 m 2 /g.

3. The lyophilized synthetic pulmonary surfactant of claim 1 , wherein the lyophilized synthetic pulmonary surfactant has a specific surface area at least 2.2 m 2 /g and porosity above 40% by volume of a total area of the lyophilized synthetic pulmonary surfactant.

4. The lyophilized synthetic pulmonary surfactant of claim 1 , wherein the lyophilized synthetic pulmonary surfactant comprises SEQ ID NO:1 (KL4 polypeptide), dipalmitoyl phosphatidylcholine (DPPC), palmitoyloleoyl phosphatidylglycerol (POPG) and palmitic acid.

5. A process of making a lyophilized synthetic pulmonary surfactant having a reduced or eliminated cake levitation during the process, the process comprising:

providing to a lyophilizing chamber a pre-lyophilization mixture comprising at least one phospholipid and a synthetic peptide dispersed in a solvent having an organic solvent in a range of between 3% (v/v) and below 20% (v/v) of the total volume of the pre-lyophilization mixture with a remainder being water and/or buffer, wherein the pre-lyophilization mixture is filled in a container and, wherein the synthetic peptide has at least 10 amino acid residues and is represented by a formula:

(Z a U b ) c Z d

wherein Z represents a hydrophilic amino acid residue and U represents a hydrophobic amino acid residue; wherein each Z is independently R, D, E or K; and each U is independently V, I, L, C, Y, or F; and wherein a is an integer with an average value of about 1 to about 5; b is an integer with an average value of about 3 to about 20; c is an integer of about 1 to about 10; and d is an integer of about 1 to about 3;

lowering a temperature inside the lyophilizing chamber to begin chilling and solidifying the pre-lyophilization mixture in a freezing phase; and

conducting an annealing phase prior to a primary drying phase and thereby reducing or eliminating cake levitation in the lyophilized synthetic pulmonary surfactant;

wherein the lyophilized synthetic pulmonary surfactant composition has a specific surface area at least 2.2 m 2 /g or a porosity above 40% by volume of a total area of the lyophilized synthetic pulmonary surfactant.

6. The process of claim 5 , the process comprising:

conducting the freezing phase in a process of lowering the temperature inside the lyophilizing chamber, wherein the pre-lyophilization mixture is chilled to a first temperature below −45° C. at a rate between 0.1 and 1.0° C./min and holding the pre-lyophilization mixture at the first temperature for a first period of time sufficient to solidify at least 76% of the solvent to form a first solidified mixture;

conducting the annealing phase and thereby reducing or eliminating cake levitation of the first solidified mixture, wherein the first solidified mixture is (i) heated to a second temperature selected to reduce or eliminate levitation of the first solidified mixture, (ii) held at the second temperature for a second period of time sufficient to reduce or eliminate levitation of the first solidified mixture, and (iii) chilled to a third temperature below −45° C. at a rate between 0.1 to 1.0° C./min to form a second solidified mixture, wherein the second solidified mixture is held at the third temperature for a third period of time sufficient to promote separation of unfrozen organic solvent from the second solidified mixture and thereby achieve a migration of the unfrozen organic solvent to an interface between the container and the second solidified mixture;

conducting a primary drying phase at a reduced pressure of 30 mT or higher, wherein the second solidified mixture is held at the third temperature for a fourth period of time sufficient to remove at least 5% of the organic solvent, followed by heating to a fourth temperature sufficient to keep the second solidified mixture from levitating in the container and retaining a structure established during the annealing phase, and further held at the fourth temperature for a fifth period of time sufficient to remove at least 70% of the solvent and thereby forming a third solidified mixture; and

conducting a secondary drying phase at the reduced pressure for a sixth period of time sufficient to produce the lyophilized synthetic pulmonary surfactant having a residual solvent content of at most 2%.

7. The process of claim 6 , wherein a ratio of the pre-lyophilization mixture's volume in the container to the container's volume is from about 28% to about 68%.

8. The process of claim 6 , wherein a ratio of a height of the pre-lyophilization mixture in the container to the container's diameter is in the range from about 0.3 to about 0.8.

9. The process of claim 6 , the process comprising providing the pre-lyophilization mixture wherein the organic solvent in the range from about 3% to about 15%.

10. The process of claim 6 , the process comprising providing the pre-lyophilization mixture wherein the organic solvent in the range from about 5% to about 10%.

11. The process of claim 6 , the process comprising providing the pre-lyophilization mixture wherein the organic solvent in the range from about 7% to about 10%.

12. The process of claim 6 , the process comprising:

conducting the freezing phase, wherein the pre-lyophilization mixture is chilled to the first temperature of −50° C.±5° C. at the rate between 0.1 and 1.0° C./min;

conducting the annealing phase, wherein the first solidified mixture is (i) heated to the second temperature of −22° C.±5° C. at a rate of 0.1 to 1.0° C./min, (ii) held at the second temperature for the second period of time between 4 and 8 hours, (iii) chilled to the third temperature of −50° C.±5° C. at a rate between 0.1 to 1.0° C./min; and (iv) held at the third temperature for the third period of time for about 3 to 8 hours;

conducting the primary drying phase at a pressure selected from the range of about 30 mT to about 200 mT and a primary drying temperature selected from the range of about −25° C. to 0° C. ramped up from −50° C.±5° C., and further held at the primary drying for at least 10 hours.

13. The process of claim 6 , the process comprising conducting the secondary drying phase at a pressure selected from the range of about 30 mT to about 200 mT and temperature of at most 46° C.±5° C.

14. The process of claim 5 , wherein the pre-lyophilization mixture comprises SEQ ID NO:1 (KL4 polypeptide), dipalmitoyl phosphatidylcholine (DPPC), palmitoyloleoyl phosphatidylglycerol (POPG) and palmitic acid and wherein the lyophilized synthetic pulmonary surfactant has a specific surface area at least 2.2 m 2 /g.

15. The process of claim 14 , wherein the specific surface area is in the range from about 3.7 m 2 /g to about 2.2 m 2 /g.

16. The process of claim 14 , wherein the lyophilized synthetic pulmonary surfactant has porosity above 40% by volume of a total area of the lyophilized synthetic pulmonary surfactant.