Solid phase method for synthesis peptide-spacer-lipid conjugates, conjugates synthesized thereby and targeted liposomes containing the same

a peptide-spacer and conjugate technology, applied in the field of solid phase synthesis of peptide-spacerlipid conjugates, can solve the problems of antibody-based targeted liposomes not using the endocytosis pathway into the interior of cells by the antigen on the cell membrane, and the toxicity of normal tissues, so as to achieve the effect of reducing product loss during synthesis

Inactive Publication Date: 2007-05-10
DEV CENT FOR BIOTECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0011] The present invention provides a convenient solid phase synthesis method for preparing peptide-PEG-lipid conjugates and provides various linkage groups (such as amide group) for conjugating a peptide, a spacer and a lipid. According to the solid phase synthesis method of the present invention, several advantages can be achieved, such as the simplified synthetic, an automated synthesis, a facile purification process in each reaction step, and minimized product losses during synthesis. In addition, the present synthesis method is suitable for preparing a wide range of peptide-spacer-lipid conjugates.

Problems solved by technology

For example, antineoplastic chemotherapies are limited by adverse side effects resulting from their widespread toxicity to normal tissues.
However, an antibody-based targeted liposome may not utilize the endocytosis pathway into the interior of the cells by the antigen on the cell membrane.
However, when the end-group functionalized PEGs are conjugated to peptide ligands, a non-homogeneous conjugation may happen if there is more than one reaction group in the peptide ligands.
Furthermore, the unreacted end-groups of functionalized PEG are difficult to define and are completely deactivate after the coupling reaction.
Although peptide-PEG-lipid conjugates are the expected molecules for preparing the targeted liposomes, the available conjugates are still very limited and the synthesis is difficult.
These properties cause difficulty in the synthetic processes of side chain protection, purification, and reaction and is evident in that very few peptide-PEG-lipid conjugates have been synthesized and in that the conjugation of a peptide, a spacer, and a lipid often induce the formation of a clumsy linker and an unusual functional group.
However, this method cannot be used as a general method for synthesizing a broad range of peptide-PEG-lipid conjugates as a nonspecific reaction of bromoacetyl group with strong nucleophilic residues, such as an amino group or other thiol group, in the peptide may occur.
Furthermore, in the YIGSR-PEG-lipid conjugate, a thioacetyl (—S—CH2-CO—) linker was used for conjugating the peptide and PEG, which is unfavorable in industrialization since an additional modification at the ends of peptide and PEG to a bromoacetyl group and a thiol group, respectively, is required.
Even though EP 1 118 336 illustrates the synthesis of the Octreotide-spacer-PEG-spacer-DOPE conjugate, the coupling of Octreotide and DOPE by a spacer-PEG-spacer involves four functional groups and three pieces of spacer, which will cause the molecules more complicated and unfavorable for molecule characterization and industrial usages.

Method used

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  • Solid phase method for synthesis peptide-spacer-lipid conjugates, conjugates synthesized thereby and targeted liposomes containing the same
  • Solid phase method for synthesis peptide-spacer-lipid conjugates, conjugates synthesized thereby and targeted liposomes containing the same
  • Solid phase method for synthesis peptide-spacer-lipid conjugates, conjugates synthesized thereby and targeted liposomes containing the same

Examples

Experimental program
Comparison scheme
Effect test

example 1

Preparation of Amino Alcohol

[0192] Preparation of Fmoc-Thr(tBu)-alcohol (Fmoc-Thr(tBu)-ol) Fmoc-Thr(tBu)-OH (1 eq, 0.663 g, 1.67 mmol) was suspended in 2 ml of ethylene glycol dimethyl ether (DME) and chilled below −15° C. under nitrogen. After addition of N-methylmorpholine (1 eq, 0.19 ml, 1.67 mmol) and isobutyl chloroformate (1 eq, 0.22 ml, 1.67 mmol), the mixture was stirred at −15° C. After 5 min of stirring, the precipitate was removed, and a suspension of NaBH4 (3 eq) in 5 ml of water was added and stirred for another 1 hr. At the end of the reaction, 40 ml of water was added. The mixture was extracted with DCM (20 ml×3), and the combined organic layers were washed with 5% NaHCO3, followed by rinsing with brine (e.g., NaCl), and being dried over anhydrous Na2SO4 (or MgSO4). The solvent was evaporated. Crude Fmoc-Thr (tBu)-alcohol was purified by silica gel column chromatography using DCM as an eluent: 1H-NMR (CDCl3) δ (Ppm): 1.16 (3H, d, J=6.2 Hz, CHCH3), 1.20 (9H, s, tBu), ...

example 2

Preparation of Peptidyl-Resins

[0193] The peptidyl-resins were prepared according to the Merrified solid phase synthesis techniques (See Steward and Young, Solid Phase Peptide Synthesis, 2nd edition, Pierce Chemical Company, Rockford, (1984) and Merrified, J. Am. Chem. Soc. 85, 2149-2154 (1963)). In the present invention, a Wang resin, a 2-chlorotrityl chloride resin, and a Rank amide resin in the Fmoc synthetic techniques were used. The Wang resin was used to synthesize the peptidyl moieties in which they have carboxylic acid moiety at a C-terminus. A 2-Chlorotrityl chloride resin was used to synthesize the peptidyl moieties in which they have Pro, Cys, or amino alcohols at a C-terminus. A Rink amide resin was used to synthesize the peptidyl moieties in which they have amide at a C-terminus. Applications of these resins in SPPS were described in the art, for examples, S.-S. Wang, J. Am. Chem. Soc., 95, 1328 (1973) and G. Lu, et al., J. Org. Chem., 46, 3433 (1981) for the Wang resin...

example 3

Synthesis of End-Group Functionalized PEG Derivatives

[0196] Carboxyl-PEG and its Active Esters

[0197] Carboxyl-PEG. PEG2000 (8.6 g) and potassium tert-butoxide (20 g) were dissolved in 300 ml tert-butyl alcohol and warmed to 40° C. Ethyl bromoacetate (10 ml) was added over a period of 20 min. The mixture was stirred for 2 hr and then evaporated to remove solvent. The residue was hydrolyzed in 200 ml of 1 N NaOH and stirred at room temperature for 2 hrs. At the end of hydrolysis, the pH of the mixture was adjusted to 2 and extracted by CHCl3 (2×200 ml). The combined extract was washed with water, dried over anhydrous MgSO4, evaporated to concentrate and dried in a vacuum. A white Carboxyl-PEG powder was obtained and yielded 6.88 g. 1H-NMR (CDCl3) δ (ppm): 3.66 (s, O—CH2CH2—O), 4.13 (s, HO—C(O)—CH2—O).

[0198] PEG-oxybenzotriazole HOBt (2.6 mmol), DIPCDI (1.91 mmol), and carboxyl-PEG3000 (0.87 mmol) were mixed in 4 ml DMF and stirred at room temperature under nitrogen for 20 min. The ...

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Abstract

A solid phase synthesis method for preparing peptide-spacer-lipid conjugates, the peptide-spacer-lipid conjugates synthesized by the method, and liposomes containing the peptide-spacer-lipid conjugates. The present invention provides a convenient solid phase synthesis method for preparing peptide-spacer-lipid conjugates and provides various linkage groups (such as amide group) for conjugating peptide, spacer and lipid, wherein the spacer may comprise PEG. Several advantages can be achieved, such as the synthetic procedure can be simplified, the synthesis process can be set to automation, the purification is easier in each reaction step, and the product losses can be reduced to minimal during synthesis. The present synthesis method is suitable for preparing a wide range of peptide-spacer-lipid conjugates, provides a peptide-spacer-lipid conjugate prepared by the solid phase synthesis method of the present invention, which can be incorporated into a liposome as the targeting moiety for liposomal drug delivery to specific cells, and provides a targeting liposome containing the present peptide-spacer-lipid conjugate.

Description

[0001] This application is a divisional of application Ser. No. 10 / 308,644 filed Dec. 3, 2002, which is a continuation-in-part of application Ser. No. 10 / 016,569 filed Dec. 7, 2001 claims the benefit thereof and incorporates the same by reference.FIELD OF THE INVENTION [0002] The present invention is related to solid phase synthesis method for preparing peptide-spacer-lipid conjugates and uses of the conjugates. BACKGROUND OF THE INVENTION [0003] Drug delivery plays a crucial role in the improvement of agents for therapeutic treatment, since many agents have unfavorable drawbacks if they are directly applied to a human body. Therefore, developing a delivery system is necessary for a particular agent to improve its availability such as reduction of side effects, enhancement of efficacy, and convenience in usage. For example, antineoplastic chemotherapies are limited by adverse side effects resulting from their widespread toxicity to normal tissues. Therefore, a delivery system which ...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): A61K38/12C07K7/64C07K5/12C07K1/02A61K9/127A61K38/00C07K1/04C07K1/107C07K14/475C07K14/48C07K14/485C07K14/49C07K14/495C07K14/50C07K14/52C07K14/575C07K14/65C07K14/655C07K14/75C07K14/78
CPCA61K9/1271C07K14/78C07K1/04C07K1/1077C07K14/4753C07K14/48C07K14/485C07K14/49C07K14/495C07K14/50C07K14/52C07K14/57563C07K14/65C07K14/655C07K14/75A61K38/00Y02P20/55A61P35/00
Inventor WU, SHIH-KWANGCHANG, TING-GUNGTSENG, GHIN-LUCHEN, LI-JUNGSHIH, KAE-SHYANG
Owner DEV CENT FOR BIOTECHNOLOGY
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