Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Web – sheet or filament bases; compositions of bandages; or...
Reexamination Certificate
2000-09-15
2001-08-14
Dodson, Shelley A. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Web, sheet or filament bases; compositions of bandages; or...
C424S444000, C424S445000, C424S446000, C424S447000, C424S449000
Reexamination Certificate
active
06274164
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to glass fiber chemical delivery systems, more particularly, to a glass particulate coated intravascular sent.
2. Prior Art
In patients suffering from certain cardiovascular diseases which cause formation of atherosclerotic plaques within blood vessels, balloon angioplasty has been somewhat successful in reopening blood vessels blocked by such plaques. In order to prevent the blood vessels from recollapsing following balloon angioplasty, it is common for a sent to be inserted into the blood vessel to act as a brace against the inner wall of the blood vessel. Typically, the sent is an expandable stainless steel mesh in which a balloon is disposed. The sent and balloon assembly is inserted into the blood vessel of the patient with a catheter. The balloon is inflated causing the sent to assume a substantially cylindrical shape and engage the walls of the blood vessel. The catheter and balloon are then withdrawn from the blood vessel and the sent remains in position to maintain the blood vessel in an open state. However, it has been found that nearly 70% of patients having intravascular stents experience restinosis in the location of the sent. The sent itself apparently is an irritant to the cells of the blood vessel wall thus stimulating plaque to reform to an even greater degree than the original blockage caused by the first treated plaque.
One solution to this problem of restinosis is to deliver a drug to the blood vessel wall which inhibits or prevents the cells of the blood vessel wall from producing plaque. In particular, certain genes have been identified which will transfect the cells of the blood vessel wall and prevent the cells from producing plaque. Such gene therapy is gaining acceptance in the treatment of cardiovascular disease; however, the delivery of a gene to a specific location within a blood vessel wall remains problematic. Moreover, such a gene or other drug delivered to the location of an intravascular sent should provide sustained relief from the formation of plaque.
Accordingly, a need remains for an intravascular sent which inhibits or prevents restinosis and for a sustained release chemical delivery system which is compatible with a biological environment or other environments.
SUMMARY OF THE INVENTION
These needs are met by the carrier composition for release of a substance and the intravascular drug delivery device of the present invention. The carrier composition includes a plurality of water soluble glass fibers. The fibers are adapted to releasably contain the substance such that the substance is released from the fibers when the fibers are dissolved in water. The fibers preferably have diameters of about four microns to five hundred microns and lengths of about twenty microns to one half inch. The glass fibers may each define a hollow core, wherein the fibers are adapted to releasably contain the substance within the hollow core. Alternatively, the glass fibers may each define at least one pore and wherein the fibers are adapted to releasably contain the substance within the pores. Suitable substances which may be contained within the glass fibers include drugs, fertilizers, biocides, chemical reactants or catalysts. In particular, a drug containing a gene may be contained within the glass fibers.
The present invention further includes a vascular drug delivery including an intravascular sent, preferably an expandable metal mesh, and a water soluble glass composition coated on the sent, wherein the glass composition includes a plurality of water soluble glass fibers and wherein the fibers releasably contain a chemical composition such as a drug. The fibers may be hollow, wherein the chemical composition is releasably contained with the core of the hollow fibers, or the fibers may be porous, wherein the chemical composition is releasably contained in the pores of the porous fibers. The fibers are preferably fixed to the sent via a layer of adhesive disposed therebetween.
The present invention further includes a method of drug delivery having the steps of providing a sustained release drug delivery system, the system including a plurality of water soluble glass fibers and a drug releasably contained within the fibers, administering said system to a human or animal and allowing the fibers to dissolve in water in the human or animal such that the drug is released from within the fibers. The system may be administered orally or parenterally, and preferably is delivered intravenously. In one embodiment, the system includes an intravascular sent, and the fibers are coated on the sent. The glass coated sent is inserted into a blood vessel of the human or animal and, as the glass dissolves, the drug is delivered to cells of a wall of the blood vessel.
The present invention also includes a method of preventing restinosis at a location of an intravascular sent having the steps of providing an intravascular sent, coating the sent with a plurality of water soluble glass fibers containing a drug adapted to prevent restinosis induced by the sent, inserting the coated sent into a blood vessel and allowing the glass fibers to dissolve in water within the blood vessel so that the fibers release the drug. Preferably, the sent bearing the drug filled glass fibers is expanded so that the fibers engage with a wall of the blood vessel and the drug is released into cells of the wall of the blood vessel. The drug may include a gene, and the drug may be releasably contained within pores in the fibers or in a central core of each of the fibers.
The fiberglass sustained release carrier composition of the present invention may be prepared by performing the steps of providing a water soluble glass composition, forming fibers of water soluble glass from the glass composition, creating pores in the fibers to produce porous water soluble fiberglass and grinding the porous water soluble fiberglass to produce ground porous water soluble fiberglass particles. The pores are preferably produced in the water soluble glass composition by reacting the glass with an acid to leach ions out from the glass composition. The substance to be released over time from the carrier composition is mixed with the ground porous water soluble fiberglass particles so that the substance enters the pores. Alternatively, the water soluble glass may be drawn through an annulus to form fibers having hollow cores. The hollow fibers are ground in a similar manner to the porous fibers and subsequently mixed with the substance to be released from the carrier composition so that the substance enters the hollow cores.
A complete understanding of the invention will be obtained from the following description when taken in connection with the accompanying drawing figures wherein like reference characters identify like parts throughout.
REFERENCES:
patent: 5470585 (1995-11-01), Gilchrist
Dodson Shelley A.
PPG Industries Ohio Inc.
Siminerio Andrew C.
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