Title:  Flexible intra-oral bandage and drug delivery system

United States Patent:  6,146,655

Assignee:  Softy-Flex Inc. (Los Angeles, CA)

Filed:  August 29, 1997

A flexible intra-oral bandage and kit thereof including an hydrolyzable powder/water-wettable fiber mixture enclosed in a flexible, water-permeable, non-stick envelope. The envelope is immersed in water or medication so that the liquid is absorbed through the envelope to wet the hydrolyzable powder/water-wettable fiber mixture and form a moldable tacky gel. The envelope is then removed from the gel and the gel is manually molded and placed in a desired location in a patient's oral cavity. The kit can also be used as a drug delivery system to deliver medication to a patient through the oral cavity.

SUMMARY OF THE INVENTION

The present invention provides a flexible intra-oral bandage which remains securely in place in a patient's mouth without irritating surrounding tissue. The bandage comprises a flexible, cohesive hydrolyzed gel/water-wettable, fiber-reinforced material. The invention also provides a kit for making the bandage, comprising a hydrolyzable powder/water-wettable fiber mixture enclosed in a flexible, water-permeable, non-stick envelope that does not adhere to the hydrolyzed gel/fiber product after wetting with an aqueous liquid. The hydrolyzable powder is preferably a water-soluble alginate salt, commonly used for forming dental impressions mixed with another salt which forms a water-insoluble alginate gel in water. The envelope is preferably a non-woven water-permeable fabric. Preferably, the hydrolyzable powder/water-wettable fiber mixture and water-permeable envelope kit is wrapped in a package having a non-adherent surface, such as a package formed of perforated aluminum foil and Mylar film. The package may also be water-permeable.

To activate the bandage, the powder/water-wettable fiber mixture enclosed in the water-permeable envelope is immersed in an aqueous liquid, such as water. Alternatively, where the outer package is water-permeable, the water-permeable package containing the hydrolyzable powder/water-wettable fiber mixture enclosed in the envelope is soaked in the aqueous liquid. The water-permeable envelope (and the water-permeable package) allows the liquid to pass through to the hydrolyzable powder-water wettable fiber mixture to wet the mixture and convert it to a moldable tacky fiber-reinforced gel. The envelope also serves to retain the alginate powder-water wettable fiber mixture while immersed in any aqueous liquid.

Although it is preferred that the "hydrolyzable powder" is particulate, i.e., non-fibrous, in nature, having a particle size relatively substantially smaller than the length of the wettable fibers, the powder can include short, fibrous, hydrolyzable particles, preferably which are much shorter in length than the wettable fibers.

The wettable fibers have an individual length of at least 3 mm, and preferably in the range of from about 2 mm to about 4 mm, to obtain the desired reinforcement effect. There should be at least one order of magnitude difference between the diameter and length of the wettable fibers. The fibers can be provided loose or by way of a preformed tissue sheet.

After the kit is removed from the liquid, the tacky fiber-reinforced gel is removed from the package and envelope, and manually molded and positioned in place over a desired tissue surface in a patient's oral cavity.

The present invention also provides a flexible intra-oral bandage and kit therefor capable of delivering medication in a water-washed environment for an extended period of time while remaining securely in place in a patient's mouth without irritating surrounding tissue. In this embodiment, the aqueous liquid in which the flexible intra-oral bandage described above is immersed comprises a solution of a liquid medication or a solid medication dissolved in water. The medication is absorbed in the bandage and the bandage is placed in the patient's mouth, as discussed above. This allows the medication to be continuously delivered to the patient through the oral cavity. The term "absorbed" is not to be limited to absorption into the interior of the fibers or the gel, but is inclusive of an external adsorption, or even coating on the fibers of the medication, or an aqueous solution thereof. Alternatively, granular medication can be dispersed in the powder/fiber mixture.

The present invention further provides an intra-oral drug delivery system capable of delivering medication in a water-washed environment for an extended period of time while remaining securely in place in a patient's mouth without irritating surrounding tissue.

Claim 1 of 17 Claims

What is claimed is:

1. A kit for preparing a flexible intra-oral bandage, the kit comprising a water-permeable envelope, the envelope being formed of a non-woven, water-porous fabric, a powder/fiber mixture contained within the envelope, the powder/fiber mixture comprising a dry, particulate water-soluble powder, comprising a soluble alginate salt admixed with a soluble reactor salt, and water-wettable fibers, the reactor salt and alginate being present in relative quantities sufficient to produce, when admixed with water, a water-insoluble cross-linked alginate salt, said fibers carrying a static electricity charge, the thickness of the fiber being an order of magnitude smaller than the length of the fiber, and the powder carrying a static electricity charge opposite to that of the fibers, and having a particle size smaller than that of the fibers; the charged powder particles being distributed on and adhering to the oppositely charged fibers; said porous envelope being so arranged to allow an aqueous liquid to pass through to and to wet said alginate-salt powder/fiber mixture when the envelope is immersed in water, and the powder/fiber mixture being so admixed that when wetted with water it is converted to a moldable, tacky fiber-reinforced gel, suitable for use as an intra-oral bandage.

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