Biodegradable lipids for the delivery of active agents
The present invention relates to a cationic lipid having one or more biodegradable groups located in a lipidic moiety (e.g., a hydrophobic chain) of the cationic lipid. These cationic lipids may be incorporated into a lipid particle for delivering an active agent, such as a nucleic acid. The invention also relates to lipid particles comprising a neutral lipid, a lipid capable of reducing aggregation, a cationic lipid of the present invention, and optionally, a sterol. The lipid particle may further include a therapeutic agent such as a nucleic acid.
1. A lipid particle comprising:
(i) a nucleic acid,
(ii) 35-65 mol % of a cationic lipid,
(iii) 3-12 mol % distearoylphosphatidylcholine (DSPC),
(iv) 15-45 mol % cholesterol, and
(v) 0.5-10 mol % of a PEG-modified lipid,
wherein the mol % is based on 100% total moles of lipids in the lipid particle; and
the cationic lipid comprises a head group, two hydrophobic tails, and a central moiety to which the head group and the two hydrophobic tails are directly bonded, wherein
(a) the central moiety is a central carbon or nitrogen atom;
(b) each hydrophobic tail independently has the formula -(hydrophobic chain)-(ester group)-(hydrophobic chain), wherein the ester group is —OC(O)— or —C(O)O—; and
(c) for at least one hydrophobic tail,
(I) the terminal hydrophobic chain in the hydrophobic tail is a branched alkyl, where the branching occurs at the α-position relative to the ester group;
(II) the hydrophobic tail has the formula —R 12 -M 1 -R 13 , wherein R 12 is a C 4 -C 14 alkylene or C 4 -C 14 alkenylene, M 1 is the ester group, and R 13 is a branched C 10 -C 20 alkyl;
(III) the total carbon atom content of the tail —R 12 -M 1 -R 13 is 21 to 26; and
(IV) the ester group is separated from a terminus of the hydrophobic tail by from 6 to 12 carbon atoms.
2. The lipid particle of claim 1 , wherein the central moiety is a nitrogen atom.
3. The lipid particle of claim 1 , wherein the cationic lipid has a pKa in the range of about 4 to about 11 and a log P of at least 10.1.
4. The lipid particle of claim 1 , wherein the ester group is —OC(O)—.
5. The lipid particle of claim 1 , wherein the ester group is —C(O)O—.
6. The lipid particle of claim 1 , wherein the PEG-modified lipid is 1-(monomethoxy-polyethylene glycol)-2,3-dimyristoylglycerol (PEG-DMG).
7. The lipid particle of claim 1 , wherein the PEG-modified lipid comprises a PEG molecule having an average molecular weight of 2,000 Da.
8. The lipid particle of claim 7 , wherein the PEG-modified lipid is 1-(monomethoxy-polyethylene glycol)-2,3-dimyristoylglycerol (PEG-DMG) comprising the PEG molecule having an average molecular weight of 2,000 Da.
9. The lipid particle of claim 1 , comprising 45-65 mol % of the cationic lipid, 5-10 mol % DSPC, 25-40 mol % cholesterol, and 0.5-5 mol % of the PEG-modified lipid.
10. The lipid particle of claim 1 , comprising about 50 mol % of the cationic lipid, about 10 mol % of DSPC, about 38.5 mol % cholesterol, and about 1.5 mol % of the PEG-modified lipid.
11. The lipid particle of claim 1 , wherein the nucleic acid comprises an RNA.
12. The lipid particle of claim 11 , wherein both hydrophobic tails have the formula —R 12 -M 1 -R 13 .
13. The lipid particle of claim 12 , wherein the chain length of —R 12 -M 1 -R 13 is at most 21 atoms from the first atom after the central moiety to a terminus of the tail.
14. The lipid particle of claim 11 , wherein, in at least one hydrophobic tail,
(i) the number of carbon atoms between the central moiety and the ester group in the hydrophobic tail ranges from 5 to 10;
(ii) the total number of carbon atoms between the central moiety and a terminus of the hydrophobic tail ranges from 15 to 20; and
(iii) the ester group is separated from a terminus of the hydrophobic tail by from 8 to 12 carbon atoms.
15. The lipid particle of claim 11 , wherein in both hydrophobic tails,
(I) the terminal hydrophobic chain in the hydrophobic tail is a branched alkyl group, where the branching occurs at the α-position relative to the ester group;
(II) the ester group is separated from a terminus of the hydrophobic tail by from 6 to 12 carbon atoms;
(III) the hydrophobic tail has the formula —R 12 -M 1 -R 13 , where R 12 is a C 4 -C 14 alkylene or C 4 -C 14 alkenylene, M 1 is the ester group, and R 13 is a branched C 10 -C 20 alkyl; and
(IV) the total carbon atom content of the tail —R 12 -M 1 -R 13 is 21 to 26.
16. The lipid particle of claim 15 , wherein the PEG-modified lipid comprises a PEG molecule having an average molecular weight of 2,000 Da.
17. The lipid particle of claim 15 , wherein the chain length of —R 12 -M 1 -R 13 is at most 21 atoms from the first atom after the central moiety to a terminus of the tail.
18. A method for preparing a lipid particle mixture comprising mixing a first solution comprising an organic solvent, a cationic lipid, distearoylphosphatidylcholine (DSPC), cholesterol, and a PEG-modified lipid, with a second solution comprising a nucleic acid and water to form a mixture containing lipid particles, wherein each lipid particle comprises
(i) the nucleic acid,
(ii) 35-65 mol % of the cationic lipid,
(iii) 3-12 mol % distearoylphosphatidylcholine (DSPC),
(iv) 15-45 mol % cholesterol, and
(v) 0.5-10 mol % of the PEG-modified lipid, and
wherein the mol % is based on 100% total moles of lipids in the lipid particle, and
the cationic lipid comprises a head group, two hydrophobic tails and a central moiety to which the head group and the two hydrophobic tails are directly bonded, wherein
(a) the central moiety is a central carbon or nitrogen atom;
(b) each hydrophobic tail independently has the formula -(hydrophobic chain)-(ester group)-(hydrophobic chain), wherein the ester group is —OC(O)— or —C(O)O—; and
(c) for at least one hydrophobic tail,
(I) the terminal hydrophobic chain in the hydrophobic tail is a branched alkyl, where the branching occurs at the α-position relative to the ester group;
(II) the hydrophobic tail has the formula —R 12 -M 1 -R 13 , wherein R 12 is a C 4 -C 14 alkylene or C 4 -C 14 alkenylene, M 1 is the ester group, R 13 is a branched C 10 -C 20 alkyl;
(III) the total carbon atom content of the tail —R 12 -M 1 -R 13 is 21 to 26; and
(IV) the ester group is separated from a terminus of the hydrophobic tail by from 6 to 12 carbon atoms.
19. The method of claim 18 , wherein the organic solvent comprises ethanol and the second solution comprises an aqueous buffer.
20. The method of claim 19 , wherein the aqueous buffer is a citrate buffer.
21. The method of claim 18 , wherein the mixing is by in-line mixing.
22. The method of claim 18 , wherein the PEG-modified lipid is 1-(monomethoxy-polyethylene glycol)-2,3-dimyristoylglycerol (PEG-DMG).
23. The method of claim 18 , wherein the PEG-modified lipid comprises a PEG molecule having an average molecular weight of 2,000 Da.
24. The method of claim 23 , wherein the PEG-modified lipid is 1-(monomethoxy-polyethylene glycol)-2,3-dimyristoylglycerol (PEG-DMG) comprising the PEG molecule having an average molecular weight of 2,000 Da.
25. The method of claim 18 , wherein the lipid particle comprises 45-65 mol % of the cationic lipid, 5-10 mol % DSPC, 25-40 mol % cholesterol, and 0.5-5 mol % of the PEG-modified lipid.
26. The method of claim 18 , wherein the lipid particle comprises about 50 mol % of the cationic lipid, about 10 mol % of distearoylphosphatidylcholine (DSPC), about 38.5 mol % cholesterol, and about 1.5 mol % of the PEG-modified lipid.
27. The method of claim 18 , wherein the nucleic acid comprises an RNA.
28. The method of claim 18 , wherein the central moiety is a nitrogen atom.
29. The method of claim 18 , further comprising diafiltering or dialyzing the lipid particle mixture.
30. The method of claim 29 , wherein the lipid particle mixture is dialyzed with phosphate-buffered saline.