Fusogenic lipids and vesicles

• US 6,858,226 B2
• Filed: 02/22/2002
• Issued: 02/22/2005
• Est. Priority Date: 04/06/1999
• Status: Expired due to Fees

• Current Assignee: ISIS Pharmaceuticals Incorporated
• Original Assignee: ISIS Pharmaceuticals Incorporated
• Inventors: Leamon, Christopher Paul
• Primary Examiner(s): NGUYEN, DAVE TRONG
• Application Number:
  US10/081,463
• Publication Number:
  US 20030082154A1
• Time in Patent Office: 1,096 Days
• Field of Search: 435/320.1, 435/455, 435/458, 514/44, 424/450
• US Class Current: 424/450
• CPC Class Codes: A61K 48/00 Medicinal preparations containing genetic material which is inserted into cells of the living body to treat genetic diseases; Gene therapy
• CPC Class Codes: A61K 9/1271 Non-conventional liposomes, e.g. PEGylated liposomes, liposomes coated with polymers liposome as conjugate A61K47/6911
• CPC Class Codes: C12N 15/1135 against oncogenes or tumor suppressor genes
• CPC Class Codes: C12N 15/88 using microencapsulation, e.g. using amphiphile liposome vesicle
• CPC Class Codes: C12N 2310/315 Phosphorothioates
• CPC Class Codes: C12N 2310/321 2'-O-R Modification
• CPC Class Codes: C12N 2310/3341 5-Methylcytosine
• CPC Class Codes: C12N 2310/346 having a combination of backbone and sugar modifications
• CPC Class Codes: C12N 2310/3525 MOE, methoxyethoxy
• CPC Class Codes: Y10S 977/907 Liposome

Abstract

Novel lipid compounds are provided that may be termed “pro-cationic” in that they are neutral or negatively charged until they are either brought into contact with cellular membranes or are internalized by cells. The lipids have a hydrophobic tail group and a hydrophilic head group, the head group incorporating both a positively and negatively charged region at physiological pH. The hydrophobic tail group is stably connected to the positive region of the head group which in turn is connected to the negative region by a disulfide bond that is susceptible to cleavage by membrane-bound and intracellular factors. Cleavage of the disulfide bond removes the negatively charged region from the head group resulting in a lipid that is cationic and therefor fusogenic with negatively charged cell membranes. Consequently, lipids of the invention are useful as components of liposomes that serve as vehicles for delivering pharmaceutical agents into cells with reduced toxicity.

Claims

1. A lipid compound and salts and hydrates thereof having the formula (I):

X—

Y—

S—

S—

Z 

 

(I)

wherein X is R₂—

Q;

Q is —

(C═

O);

R₂ is a steroid;

Y is —

NH—

(CH₂)₂—

NH—

C(═

NH₂³⁰ )—

(CH₂)₃—

;

Z is alkyl substituted with a targeting molecule attached via a linking group;

provided that at a physiological pH, X and Y together have a net positive charge and Z has a net negative charge.

2. The compound of claim 1 wherein R₂ is cholesterol.

3. A lipid compound according to claim 1 having the formula: