Surgery: splint – brace – or bandage – Bandage structure – Skin laceration or wound cover
Reexamination Certificate
1999-01-21
2001-06-26
Lewis, Kim M. (Department: 3761)
Surgery: splint, brace, or bandage
Bandage structure
Skin laceration or wound cover
C602S041000, C239S003000, C239S697000
Reexamination Certificate
active
06252129
ABSTRACT:
This invention relates to methods and devices for forming material. In one example, this invention relates to methods and devices for applying material to a surface, for example to an internal or external surface of an animal, for example for applying material to skin for use, for example, in the care or treatment of wounds or burns.
Various forms of aerosol devices for allowing material to be sprayed onto a surface such as the human skin are known, including aerosol devices for spraying wound care products onto wounds or burns. One such product is Savlon Dry (trade mark) which has been marketed in the UK by Zyma Healthcare and Ciba Geigy plc. Such products require the use of a gas propellant and in recent years the choice of gas propellants has become more limited because of the desire to avoid environmentally unfriendly compounds such as a chlorofluorocarbons or hydrocarbons. Also because small droplets and powder particles tend to be carried away from the target by the gas flow created when the propellant gas hits and is deflected by the target surface, such gas propelled sprays are generally designed to spray relatively large droplets or powder particles in order to achieve sufficient inertia to deposit the spray on its target surface. Such gas propelled products may run if sprayed too freely, especially where the spray produces large droplets. In addition, the packaging costs for such devices are high.
GB-A-1569707 describes a dispensing device for producing a spray or cloud of liquid droplets intended primarily for crop spraying. The process described in GB-A-1569707 produces liquid droplets by applying an electric field to a liquid emerging from an outlet in the vicinity of the surface so that the liquid becomes sufficiently charged that the net electric charge in the liquid as the liquid emerges into free space counteracts the surface tension forces of the liquid and the repulsive forces generated by the like electrical charges cause the liquid to be comminuted to produce a cone or jet which breaks into liquid droplets. The droplets produced by this device are charged close to their Rayleigh Limit and thus in use migrate quickly toward conductive surfaces of lower or zero potential. This technique of comminuting liquid is generally known as electrohydrodynamic comminution.
In one aspect, the present invention provides a method and/or a device for forming solid, partially solid or gel-like matter such as fibres, fibrils or fibre fragments or segments, droplets or particles by an electrohydrodynamic process. The thus formed matter may incorporate or have a core of a different material which may be for example a biologically active ingredient or material. The formed matter may be applied to a surface or area such as, for example, the surface of the skin or a wound or burn or to a cavity, for example a body cavity. The body cavity may be the respiratory system of an animal such as a human being, where the electrohydrodynamic process produces matter that does not block the respiratory system.
Where the resulting matter or material is to be applied or supplied to a cavity or concave surface, then desirably the matter is at least partially electrically discharged before application or supply.
In another aspect, the present invention provides a method or device for forming a mat or web by electrohydrodynamically forming electrically charged fibres and/or fibrils in the vicinity of a surface or substrate. The present invention also provides a mat or web formed using an electrohydrodynamic process.
In an aspect, the present invention provides a method or device for applying material to a surface by supplying to an electrohydrodynamic site located in the vicinity of the surface liquid which is electrohydrodynamically processed at the site in such a manner so as to form matter comprising at least partially solid or gel-like fibres, fibre fragments or fibrils or particles which are charged and are electrostatically attracted to the said surface enabling a mat or web of randomly distributed fibres and/or fibrils and/or particles to be formed on the surface. The location at which the matter is deposited on the surface can be at least partially controlled by effecting relative movement between the surface and the matter.
In another aspect, the present invention provides a method of applying material to an exposed surface of an animal, for example to the skin or to a wound or burn or area exposed by a surgical procedure, which comprises producing material comprising at least one of electrically charged fibres, fibre fragments or fibrils or droplets or particles in the vicinity of the said surface area by an electrohydrodynamic process, so that the material deposits on the said area.
In another aspect, the present invention provides a method of forming fibre fragments or fibrils by supplying liquid to an electrohydrodynamic site and deliberately perturbing the cone or jet issuing from the comminution site to cause the resulting fibre to break up into fragments. The break up of the fibre may be promoted by pulsing the voltage used for the electrohydrodynamic process. The length of the fibrils may be controlled by adjusting the frequency of the pulses.
In another aspect, the present invention provides a method of forming at least partly solid droplets or particles by supplying liquid to an electrohydrodynamic comminution site.
In an example, the present invention provides a method of depositing fibre s on a surface, for example to form a dressing for a surface area of an animal for example an area of skin, a wound or burn or for other therapeutic or cosmetic reasons, which comprises supplying liquid comprising polylactic acid having a molecular weight in the region of 144000, dissolved 10% by mass in acetone at approximately 10 milliliters per hour to an electrohydrodynamic comminution site located at about 5 to 10 cm above the surface.
In another example, the present invention provides a method of depositing fibres on a surface, for example to form a dressing for a surface area of an animal for example an area of skin, a wound or burn or for other therapeutic or cosmetic reasons, which comprises subjecting liquid comprising a biocompatible polymer which may be bioresorbable or biodegradable polymer such as polylactic acid, polygylcolic acid, polyvinyl alcohol or polyhydroxybutyric acid to an electrohydrodynamic process in the vicinity of said area.
In an embodiment, the deposition process may be repeated one or more times to provide a number of layers of material comprising at least one of fibres, fibrils, droplets or particles on the surface. The polarity to which the material is charged may be reversed between deposition of different layers so as facilitate attraction between the layers.
The liquid used to produce the electrohydrodynamically formed matter may comprise a biologically active ingredient or component where the electrohydrodynamically formed material comprises fibrils, the fibrils may actually stick into the skin of soft tissue enabling delivery of the active component to a location beneath the outer layer of skin or soft tissue.
The liquid used may comprise a solution, suspension, microsuspension, emulsion, microemulsion, gel or even a melt which may contain an active component or components. Alternatively or additionally, the active component may be provided as a coating or a core of the fibre, fibril or particle. For example microcapsules, fibres or fibrils of a bioresorbable or biodegradable polymer may be formed which contain a biologically active ingredient. Material from the core of a fibre or fibril may be released from the ends of the fibre or fibril. Material from the core of a fibre, fibril or microcapsule may be released through the coating if the coating is permeable to the material contained within it or may be released as a result of the outer coating being breached, for example by chemical or enzymic attack which causes the outer coating to dissolve or degrade, by bioresorption or biodegradation of the coating, or as a result of temperature changes or appli
Cobrin & Gittes
Electrosols Ltd.
Lewis Kim M.
LandOfFree
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