Magnetically-localizable, polymerized lipid vesicles and method of disrupting same

• US 4,652,257 A
• Filed: 03/21/1985
• Issued: 03/24/1987
• Est. Priority Date: 03/21/1985
• Status: Expired due to Fees

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Chang, Eddie L.
• Primary Examiner(s): YASKO JR, JOHN D
• Application Number:
  US06/714,411
• Time in Patent Office: 733 Days
• Field of Search: 604/52, 604/51, 604/57, 604/65, 128/1.3, 128/1.1
• US Class Current: 604/20
• CPC Class Codes: A61K 9/1273 Polymersomes; Liposomes with polymerisable or polymerised bilayer-forming substances polymers grafted or coated on phosphatidyl liposomes A61K9/1271, on non-phosphatidyl liposomes A61K9/1272
• CPC Class Codes: A61M 31/002 Devices for releasing a drug at a continuous and controlled rate for a prolonged period of time artificial gland structures or devices A61F2/022; intra-uterine contraceptive devices A61F6/14; tampons for introducing into the vagina A61F13/20, A61L15/00; suppositories or bougies for intra-vaginal or intra-uterine application A61K9/02; physical forms of medicinal preparations for sustained or differential drug release A61K9/20, A61K9/50
• CPC Class Codes: A61M 37/00 Other apparatus for introducing media into the body for reproduction or fertilisation A61B17/425; apparatus for iontophoresis or cataphoresis A61N1/30; Percutany, i.e. introducing medicines into the body by diffusion through the skin salt baths A61H33/04

Abstract

Polymerizable lipids are used to encapsulate therapeutic agents and ferronetic particles into lipid vesicles. The vesicles are polymerized, injected into the body upstream of a targeted capillary bed, allowed to flow within the bloodstream to the targeted site, and held there by an externally applied magnetic field. The magnetic field is oscillated at sufficient periodicity to destabilize or disrupt the vesicle membrane thus effecting a controlled release of the therapeutic agent.

Claims

1. A method of delivering a therapuetic agent to a target site within the body, comprising the steps of:

introducing ferromagnetic particle embedded vesicles containing said therapuetic agent into the blood stream upstream of said target site;

applying a magnetic field having sufficient strength to immobilize said vesicles at said target site;

immobilizing said vesicles at said target site; and

oscillating said magnetic field at a rate sufficient to vibrate said ferromagnetic particles such that said vesicles'"'"'s membrane is destabilized or lysed thereby controlling the rate of release of said therapuetic agent at said target site.

2. The method of claim 1 wherein said ferromagnetic particles are selected from the group consisting of monodomain size magnets from magnetic sensing bacteria, magnetics, ferrites, and fine iron filings, having a average particle size between 100 and 500 angstroms.

3. The method of claim 2 wherein said magnetic field is about 5000-12000 Gauss.

4. The method of claim 3 wherein said magnetic field is about 7000-9000 Gauss.

5. The method of claim 4 wherein said oscillation rate is about 10-1500 Hertz.

6. The method of claim 5 wherein said oscillation rate is about 500-1000 Hertz.