Generation of therapeutic microfoam

• US 6,942,165 B1
• Filed: 05/26/2000
• Issued: 09/13/2005
• Est. Priority Date: 05/26/1999
• Status: Expired due to Term

• Current Assignee: BTG International Limited (Boston Scientific Corporation)
• Original Assignee: BTG International Limited (Boston Scientific Corporation)
• Inventors: Harman, Anthony David, Wright, David Dakin Iorwerth, Osman, Tariq, Boorman, Timothy David, Shilton-Brown, Sheila Bronwen
• Primary Examiner(s): DOERRLER, WILLIAM CHARLES
• Application Number:
  US09/979,655
• Time in Patent Office: 1,936 Days
• Field of Search: 239/337, 424/600, 424/423, 424/489, 424/484, 424/DIG.7, 424/400, 514/706, 514/708, 514/709, 514/945, 604/140
• US Class Current: 239/337
• CPC Class Codes: A61K 31/08 acyclic, e.g. paraformaldehyde
• CPC Class Codes: A61K 9/0019 Injectable compositions; Intramuscular, intravenous, arterial, subcutaneous administration; Compositions to be administered through the skin in an invasive manner non-active ingredients are additionally classified in A61K47/00
• CPC Class Codes: A61K 9/122 Foams; Dry foams edible foams A61K9/0056
• CPC Class Codes: A61P 9/00 Drugs for disorders of the cardiovascular system
• CPC Class Codes: A61P 9/14 Vasoprotectives; Antihaemorrhoidals; Drugs for varicose therapy; Capillary stabilisers
• CPC Class Codes: B05B 11/02 Membranes or pistons acting on the contents inside the container, e.g. follower pistons
• CPC Class Codes: B05B 7/0037 including sieves, porous members or the like
• CPC Class Codes: B65D 83/14 for delivery of liquid or semi-liquid contents by internal gaseous pressure, i.e. aerosol containers comprising propellant for a product delivered by a propellant
• CPC Class Codes: B65D 83/20 operated by manual action, e.g. button-type actuator or actuator caps actuators formed as a rigid elongate spout B65D83/306
• CPC Class Codes: B65D 83/48 Lift valves, e.g. operated by push action B65D83/50 takes precedence
• CPC Class Codes: B65D 83/60 Contents and propellant separated
• CPC Class Codes: B65D 83/62 by membrane, bag, or the like containers in which the content is delivered by the contracting forces inherent in the bag B65D83/0061

Abstract

Improved therapeutic sclerosing microfoams and methods and devices for making them are provided that have advantage in producing a consistent profile injectable foam with minimal input by the physician yet using high volume percentages of blood dispersible gases, thus avoiding use of potentially hazardous amounts of nitrogen.

Claims

1. A device for producing a microfoam suitable for use in sclerotherapy of blood vessels comprising a housing in which is situated a pressurisable chamber containing an aqueous sclerosant liquid;

a pathway with one or more outlet orifices by which the liquid may pass from the pressurisable chamber to exterior of the device through one or more outlet orifices and a mechanism by which the pathway from the chamber to the exterior can be opened or closed such that, when the container is pressurised and the pathway is open, fluid in the chamber will be forced along the pathway and through the one or more outlet orifices

said housing including one or more of (a) a pressurised source of physiologically acceptable gas that is dispersible in blood and (b) an inlet for admission of said gas;

the gas being contacted with the liquid on activation of the mechanism such as to produce a gas liquid mixture

said pathway to the exterior of the housing includes one or more elements defining one or more passages of cross-sectional dimension 0.1 μ

m to 30 μ

m, through which the gas liquid mixture is passed to reach the exterior of the device, said passing of the mixture through the passages forming a microfoam of from 0.07 to 0.19 g/ml density and having a half-life of at least 2 minutes.

2. A device as claimed in claim 1 further comprising a gas liquid interface junction, prior to the passages, the junction controlling the ratio of gas to liquid passing through it such as to produce the required density microfoam.

3. A device as claimed in claim 1 characterised in that the ratio of gas and liquid in the mixture is controlled such that the microfoam is from 0.09 to 0.16 g/ml density.

4. A device as claimed in claim 2 wherein the housing includes a chamber charged with the blood dispersible gas and the sclerosant liquid, the pathway including a dip-tube with an inlet opening in liquid in the chamber.

5. A device as claimed in claim 4 wherein the dip-tube has an outlet opening at the gas liquid interface junction where the gas has access to the pathway to the pathway to the one or more outlet orifices.

6. A device as claimed in claim 1 wherein the pathway is opened or closed by a valve having an actuator element that is depressed or tilted to open up a pathway to the exterior, whereby said liquid rises up the dip-tube under gas pressure and is mixed in the interface junction with said gas to produce an aerosol, dispersion of bubbles in liquid or macrofoam.

7. A device as claimed in claim 1 wherein the one or more elements having one or more passages of 0.1 μ

m to 30 μ

m cross-sectional dimension are mounted inside the chamber in the pathway to the valve, such that the gas liquid mixture passes through the passage or passages and is caused to produce said microfoam.

8. A device as claimed in claim 1 wherein the one or more elements having one or more passages of 0.1 μ

m to 30 μ

m cross-sectional dimension are mounted on the downstream side of the valve, such that the gas liquid mixture passes through the passage or passages and is caused to produce said microfoam.

9. A device as claimed in claim 8 wherein the one or more elements are located in a cap mounted on the valve, upstream of the gas liquid interface, the cap including an outlet nozzle.

10. A device as claimed in claim 7 wherein the one or more elements are located within the housing mounted between the gas liquid interface and the valve.

11. A device as claimed in claim 1 characterised in that the gas liquid interface junction comprises holes in the dip tube above the surface of the liquid in use.

12. A device as claimed in claim 4 characterised in that the chamber is pressurised at 0.01 to 9 bar over atmospheric.

13. A device as claimed in claim 1 characterised in that the aqueous sclerosant liquid is contained within a second flexible gas and liquid tight disposed within the pressurisable chamber, the second chamber being sealed around the dip-tube.

14. A device as claimed in claim 13 characterised in that the dip-tube has a one-way valve positioned between the gas liquid interface junction and the dip-tube opening within the second flexible chamber, which when the pathway to the exterior of the device is closed, also remains closed such as to separate the liquid from the physiologically acceptable blood dispersible gas around it in the chamber and on opening the pathway to the exterior, the one way valve also opens and releases liquid up the dip-tube to the gas liquid interface junction where an aerosol, dispersion of bubbles in liquid or macrofoam is produced which is passed through the passages and converted to microfoam.

15. A device as claimed in claim 1 wherein the one or more elements defining one or more passages are provided in the form of porous membranes, meshes, screens or sinters.

16. A device as claimed in claim 1 characterised in that it comprises a series of the elements defining said passages arranged in parallel with their major surfaces perpendicular to the pathway.

17. A device for delivering microfoam to a syringe from a microfoam generating device as claimed in claim 1 characterised in that it comprises an inlet conduit for engaging the outlet of the microfoam producing device in a microfoam tight fashion, the conduit being connected to and leading through a multipath valve for directing microfoam passing down the conduit, the valve being capable of being set to direct microfoam down either of first and second outlet conduits or for closing the inlet conduit, the syringe luer outlet being received by one of the first and second outlet conduits.

18. A device as claimed in claim 17 further comprising one or more elements for engaging the microfoam producing device other than by its outlet nozzle to hold it securely.

19. A device as claimed in claim 1 further comprising a base element, sufficiently stable to mount a microfoam producing device adjacent a multipath-valve said inlet being attachable to the microfoam producing device outlet conduit.

20. A device as claimed in claim 19 further comprising an activating element which operates to cause the pathway within the microfoam producing device to be opened to the inlet conduit.