INTRAUTERINE DEVICE
United States Patent 3834378
An intrauterine device composite is provided which comprises a plastic matrix, such as a copolymer of ethylene and vinyl acetate, having a particulate material selected from the group consisting of metals such as copper, zinc, silver, platinum, or cadmium, and metal salts dispersed within the matrix. The particulate preferably includes both a metal and a salt, such as a sulfate, thereof, although solely a salt or a metal particulate may be utilized. In addition, a radio-opaque particulate such as barium sulfate is preferably also dispersed within the composite. The particulate material preferably comprises between 0.1% to 50% by weight of the composite, and the matrix preferably has a water permeability or rate of water vapor transmission of at least 0.3 grams/100 square inches/24 hours/mil at 25° C.
US Patent References:
Intrauterine device
Ahmed - February 1967 - 3306286
INTRAUTERINE CONTRACEPTIVE METHOD
Zipper - February 1971 - 3563235
INTRAUTERINE CONTRACEPTIVE DEVICE
Lerner - January 1972 - 3633574
Intrauterine device
Ahmed - February 1967 - 3306286
INTRAUTERINE CONTRACEPTIVE METHOD
Zipper - February 1971 - 3563235
INTRAUTERINE CONTRACEPTIVE DEVICE
Lerner - January 1972 - 3633574
Inventors:
Lerner, Irwin S. (Greenwich, CT)
Davis, Hugh J. (Baltimore, MD)
Earl, Thad J. (Defiance, OH)
Davis, Hugh J. (Baltimore, MD)
Earl, Thad J. (Defiance, OH)
Application Number:
05/336066
Publication Date:
09/10/1974
Filing Date:
02/26/1973
View Patent Images:
Export Citation:
Assignee:
A. H. Robins Company, Incorporated (Richmond, VA)
Primary Class:
Other Classes:
424/432
International Classes:
A61F6/14; A61B19/00; A61F6/00; A61F5/46
Field of Search:
128/130,131 424/14,16,22
Primary Examiner:
Gaudet, Richard A.
Assistant Examiner:
Dunne G. F.
Attorney, Agent or Firm:
Strauch, Nolan, Neale, Nies & Kurz
Parent Case Data:
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation of application Ser. No. 88,538 filed Nov. 12, 1970 and now abandoned.
Claims:
What is claimed is
1. An intrauterine device having a body structure encompassing an area which can be contained within a normal uterus, made from a composition enabling flexing to conform to the uterine cavity comprising: a plastic matrix, and a particulate material comprising at least one non-magnetic metal selected from a group consisting of copper, zinc, silver, platinum and cadmium, and at least one salt of a metal selected from said group; said particulate material being dispersed within said plastic matrix; and said particulate material comprising between 0.1% to 10% by weight of the composition of said device.
2. An intrauterine device having a composition in accordance with claim 1, wherein said particulate material comprises a metal and a salt of said metal.
3. An intrauterine device having a composition in accordance with claim 1, wherein the material comprising said plastic matrix has a water permeability of at least 0.3 grams/100 square inches/24 hours/mil at a temperature of 25° Centigrade.
4. An intrauterine device having a composition in accordance with claim 1, wherein the material comprising said plastic matrix has a water permeability of at least 10 grams/100 square inches/24 hours/mil at a temperature of 25° Centigrade.
5. An intrauterine device having a composition in accordance with claim 1, wherein said material comprising the plastic matrix is a copolymer of ethylene and a vinyl monomer material.
6. An intrauterine contraceptive device made from a composition material as defined in claim 1 enabling flexing to conform to the uterine cavity, further comprising: a central body having a perimeter portion with nose, tail and side portions and encompassing an area which can be contained within a normal uterus, and at least three spaced apart short spurs on each of said side portions extending outwardly from said perimeter portion.
7. An intrauterine device having a composition in accordance with claim 6, wherein said material comprising the plastic matrix is a copolymer of ethylene and a vinyl monomer material.
8. An intrauterine contraceptive device made from a composition material as defined in claim 1 enabling flexing to conform to the uterine cavity, further comprising; a ring-like perimeter portion having a nose portion and opposite therefrom a tail portion with side portions joining said nose and tail portions; and a plurality of spur-like retaining means extending outwardly from each said side portion.
9. An intrauterine device having a composition in accordance with claim 8, wherein said particulate material comprises a metal and a salt of said metal.
10. An intrauterine device having a composition in accordance with claim 9, wherein said material comprising the plastic matrix is a copolymer of ethylene and a vinyl monomer material.
11. An intrauterine device having a body structure encompassing an area which can be contained within a normal uterus, made from a composition enabling flexing to conform to the uterine cavity comprising: a plastic matrix, and a particulate material comprising at least copper and a salt of copper; said particulate material being dispersed within said plastic matrix; and said particulate material comprising between 0.1% to 10% by weight of the composition of said device.
12. An intrauterine device having a composition in accordance with claim 11; wherein said particulate material comprises copper and cupric sulfate.
13. An intrauterine device having a composition in accordance with claim 12, wherein the material comprising said plastic matrix has a water permeability of at least 0.3 grams/100 square inches/24 hours/mil at a temperature of 25° Centigrade.
14. An intrauterine device having a composition in accordance with claim 12, wherein the material comprising said plastic matrix has a water permeability of at least 10 grams/100 square inches/24 hours/mil at a temperature of 25° Centigrade.
15. An intrauterine contraceptive device made from a composition material as defined in claim 12, enabling flexing to conform to the uterine cavity, further comprising: a central body having a perimeter portion with nose, tail and side portions and encompassing an area which can be contained within a normal uterus, and at least three spaced apart short spurs on each of said side portions extending outwardly from said perimeter portion.
16. An intrauterine contraceptive device made from a composition material as defined in claim 12, enabling flexing to conform to the uterine cavity, further comprising; a ring-like perimeter portion having a nose portion and opposite therefrom a tail portion with side portions joining said nose and tail portions; and a plurality of spur-like retaining means extending outwardly from each said side portion.
17. An intrauterine device having a body structure encompassing an area which can be contained within a normal uterus, made from a composition enabling flexing to conform to the uterine cavity comprising: a plastic matrix, and a particulate material comprising at least copper and at least one salt of a metal selected from a group consisting of copper, zinc, silver, platinium and cadmium; said particulate material being dispersed within said plastic matrix; and said particulate material comprising between 0.1% to 10% by weight of the composition of said device.
1. An intrauterine device having a body structure encompassing an area which can be contained within a normal uterus, made from a composition enabling flexing to conform to the uterine cavity comprising: a plastic matrix, and a particulate material comprising at least one non-magnetic metal selected from a group consisting of copper, zinc, silver, platinum and cadmium, and at least one salt of a metal selected from said group; said particulate material being dispersed within said plastic matrix; and said particulate material comprising between 0.1% to 10% by weight of the composition of said device.
2. An intrauterine device having a composition in accordance with claim 1, wherein said particulate material comprises a metal and a salt of said metal.
3. An intrauterine device having a composition in accordance with claim 1, wherein the material comprising said plastic matrix has a water permeability of at least 0.3 grams/100 square inches/24 hours/mil at a temperature of 25° Centigrade.
4. An intrauterine device having a composition in accordance with claim 1, wherein the material comprising said plastic matrix has a water permeability of at least 10 grams/100 square inches/24 hours/mil at a temperature of 25° Centigrade.
5. An intrauterine device having a composition in accordance with claim 1, wherein said material comprising the plastic matrix is a copolymer of ethylene and a vinyl monomer material.
6. An intrauterine contraceptive device made from a composition material as defined in claim 1 enabling flexing to conform to the uterine cavity, further comprising: a central body having a perimeter portion with nose, tail and side portions and encompassing an area which can be contained within a normal uterus, and at least three spaced apart short spurs on each of said side portions extending outwardly from said perimeter portion.
7. An intrauterine device having a composition in accordance with claim 6, wherein said material comprising the plastic matrix is a copolymer of ethylene and a vinyl monomer material.
8. An intrauterine contraceptive device made from a composition material as defined in claim 1 enabling flexing to conform to the uterine cavity, further comprising; a ring-like perimeter portion having a nose portion and opposite therefrom a tail portion with side portions joining said nose and tail portions; and a plurality of spur-like retaining means extending outwardly from each said side portion.
9. An intrauterine device having a composition in accordance with claim 8, wherein said particulate material comprises a metal and a salt of said metal.
10. An intrauterine device having a composition in accordance with claim 9, wherein said material comprising the plastic matrix is a copolymer of ethylene and a vinyl monomer material.
11. An intrauterine device having a body structure encompassing an area which can be contained within a normal uterus, made from a composition enabling flexing to conform to the uterine cavity comprising: a plastic matrix, and a particulate material comprising at least copper and a salt of copper; said particulate material being dispersed within said plastic matrix; and said particulate material comprising between 0.1% to 10% by weight of the composition of said device.
12. An intrauterine device having a composition in accordance with claim 11; wherein said particulate material comprises copper and cupric sulfate.
13. An intrauterine device having a composition in accordance with claim 12, wherein the material comprising said plastic matrix has a water permeability of at least 0.3 grams/100 square inches/24 hours/mil at a temperature of 25° Centigrade.
14. An intrauterine device having a composition in accordance with claim 12, wherein the material comprising said plastic matrix has a water permeability of at least 10 grams/100 square inches/24 hours/mil at a temperature of 25° Centigrade.
15. An intrauterine contraceptive device made from a composition material as defined in claim 12, enabling flexing to conform to the uterine cavity, further comprising: a central body having a perimeter portion with nose, tail and side portions and encompassing an area which can be contained within a normal uterus, and at least three spaced apart short spurs on each of said side portions extending outwardly from said perimeter portion.
16. An intrauterine contraceptive device made from a composition material as defined in claim 12, enabling flexing to conform to the uterine cavity, further comprising; a ring-like perimeter portion having a nose portion and opposite therefrom a tail portion with side portions joining said nose and tail portions; and a plurality of spur-like retaining means extending outwardly from each said side portion.
17. An intrauterine device having a body structure encompassing an area which can be contained within a normal uterus, made from a composition enabling flexing to conform to the uterine cavity comprising: a plastic matrix, and a particulate material comprising at least copper and at least one salt of a metal selected from a group consisting of copper, zinc, silver, platinium and cadmium; said particulate material being dispersed within said plastic matrix; and said particulate material comprising between 0.1% to 10% by weight of the composition of said device.
Description:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to intrauterine device composites and more particularly to such composites comprising a plastic matrix having a particulate material dispersed therein.
2. Description of the Prior Art
Prior art intrauterine devices have utilized structures including a metal wire in order to obtain improved results. Such prior art devices have involved the use of a plastic T-shaped device having a fine copper wire wrapped about the upper end of the stem of the T, a silkworm gut wrapped in a bronze wire, and a copper loop having a silkworm gut tail. These prior art intrauterine devices, however, are bulky, difficult to insert, and are not necessarily well tolerated within the uterine cavity. Moreover, whenever any beneficial effect has been observed, a substantial quantity of time has been required before such beneficial effects occur, resulting in a lag time between insertion of the device and achievement of the benefits thereof. In addition, in intrauterine devices employing a wire wrapped about a T-stem, the wire tends to dissolve and break up thus minimizing its long range effectiveness. Furthermore, such prior art devices have a relatively low surface area for the metal which, thereby, also minimizes their effectiveness. Due to these disadvantages, prior art intrauterine devices have not achieved the wide spread usage enjoyed by oral contraceptives. The present invention overcomes these disadvantages of the prior art.
SUMMARY OF THE INVENTION
An intrauterine device composite is provided which comprises a plastic matrix having a particulate material dispersed within the matrix. The particulate material is selected from the group consisting of metals and metal salts and comprises between 0.1% and 50% by weight of the composite. The particulate preferably includes both a metal and a salt, such as a sulfate thereof, although solely a metal or a salt particulate may be utilized. In addition, a radio-opaque particulate, such as barium sulfate, is preferably also dispersed within the matrix. The plastic matrix preferably has a water permeability or rate of water vapor transmission of at least 0.3 grams/100 square inches/24 hours/mil at 25° C.
BREIF DESCRIPTION OF THE DRAWING
The FIGURE is a diagrammatic illustration exemplary of an intrauterine device composite in accordance with the preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
For purposes of illustration, an intrauterine device of the type commonly termed a "shield," such as described in co-pending application, Ser. No. 775,729, filed on Nov. 14, 1968, now U.S. Pat. No. 3,633,574, generally referred to by the reference numeral 10, is shown. The shield device 10 disclosed in co-pending application, Ser. No. 775,729, preferably has a contour which conforms to the mid-range of the uterine cavity, and has a plurality of lateral fins 12--12 which promote retention and permit accommodation to uterine contractions and variations in uterine shape extending outwardly from a central membrane portion 14. As disclosed in copending application, Ser. No. 775,729, the central membrane portion 14 increases endometrial surface contact, as well as precludes bowel strangulation in the event of perforation. However, the present invention is not limited to the shield type of intrauterine device, but rather is applicable to all types of intrauterine devices, the shield type 10 only being shown and described by way of example.
Preferably, the intrauterine device 10, as shown and preferred in the FIGURE, is a composite formed of a plastic material such as a copolymer of ethylene and vinyl acetate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl chloride, nylon, or silicone rubber, such as disclosed in co-pending patent application, Ser. No. 775,729. Most preferably, the plastic material is a copolymer of ethylene and vinyl acetate, such as UE 632, manufactured by United States Industrial Chemical Corporation, which contains 13-15% vinyl acetate by weight. As shown and preferred, in addition, the plastic matrix of which the intrauterine device 10 is preferably constructed, has dispersed therein particulate material. Most preferably, the particulate is dispersed throughout the plastic matrix. The particulate material preferably includes a metal and a salt thereof, although it may comprise solely a metal or a salt. By way of example, metals which are satisfactory for purposes of the present invention are copper, zinc, silver, platinum, or cadmium. Most preferably, copper particulate is preferred. By way of example, metal salts which are satisfactory include salts of copper, zinc, silver, platinum, or cadmium. The salt is preferably a sulfate, carbonate, nitrate, acetate or phosphate. Most preferably, the salt is a sulfate of the metal particulate.
Preferably, the particulate metal in the intrauterine device composite 10 is at least 0.1% by weight of the overall composite. The metal salt is, preferably, at least 0.5% by weight of the overall composite. In addition, the preferred overall content of metal plus metal salt in the composite should not exceed 50% by weight of the overall composite, thereby providing a preferred range of total particulate, by weight, in the overall composite of between 0.1% to 50% by weight.
The requisite amount of particulate material, which is biologically active, is preferably related to the water permeability or rate of water vapor transmission of the plastic matrix, which is biologically inert. The greater the permeability of the plastic, the less the requisite amount of active particulate that need be present. Conversely, the lower the permeability, the greater the requisite amount of active particulate that should preferably by present. Preferably the water permeability or rate of water vapor transmission of the plastic is at least 0.3 grams/100 square inches/24 hours/mil at 25° C.. If desired, better results may be obtained with a water permeability of at least 5 grams/100 square inches/24 hours/mil at 25° C.. Most preferably this rate is at least 10 grams/100 square inches/24 hours/mil at 25° C..
In addition to the presence of a particulate of a metal and a salt thereof in the preferred composite, a radio-opaque particulate material may also be dispersed therein. Preferably, this radio-opaque material is a salt of an alkaline earth metal, such as barium. Most preferably, this salt is barium sulfate.
In order to form the intrauterine device composite, conventional techniques may be utilized. Once such preferred conventional technique requires intimately admixing particles of the desired plastic with finely ground particulate metal and particulate metal salts at a sufficiently high temperature for a sufficient time in order to obtain a homogeneous-like phase. The resultant impregnated plastic having the particulate material dispersed throughout is then molded under heat and pressure in a conventional manner to readily form any desired configuration such as the shield configuration 10 illustrated in the FIGURE.
The resulting intrauterine device compsite consists of a plastic matrix having the particulate material dispersed throughout the matrix. This is illustratively shown by the particulate, generally referred to by the reference numeral 16, shown in the FIGURE. Most preferably, the intrauterine device composite comprises a plastic matrix of a copolymer of ethylene and vinyl acetate having a particulate of copper and cupric sulfate dispersed throughout the matrix, with the percent by weight of the copper and cupric sulfate particulate being between 0.5% to 10% by weight of the composite, and the water permeability of the plastic being at least 10 grams/100 square inches/24 hours/mil at 25° C..
The presence in the water permeable plastic matrix of the biologically active metal particulate which preferably does not exceed an amount which degrades the plastic matrix so as to eliminate the beneficial flexibility thereof, assists the tensile strength, flowability for molding and other physical properties of the intrauterine device composite. In addition, the presence of the metal salt particulate, which is preferably a salt which is capable of relatively rapid ionization after insertion of the intrauterine device composite within the uterine cavity, is believed to ionize much more rapidly than the free metal particulate and causes rapid release of metal ions. When only a metal salt particulate is utilized, the ionization of the salt provides early protection, whereas protection at a later time is provided by the chemotactic effect of the plastic matrix. Preferably, the biologically active particulate is capable of enhancing the chemotactic effect of the otherwise relatively inert plastic material. By virtue of the "controlled release" of the biologically active particulate, relatively low concentrations thereof are capable of exerting a gameto toxic effect.
Whether the presence of the metal salt and/or metal exerts a spermicidal and/or ovacidal action or causes the tissue to react in such a manner so as to produce a material which itself is spermicidal and/or ovacidal, the presence of the metal in the ion state accelerates this action, and the rapid ionization of the metal salt enhances this result.
By utilizing an intrauterine device composite in accordance with the preferred embodiment of the present invention, the properties and capabilities of an intrauterine device are markedly enhanced.
1. Field of the Invention
The present invention relates to intrauterine device composites and more particularly to such composites comprising a plastic matrix having a particulate material dispersed therein.
2. Description of the Prior Art
Prior art intrauterine devices have utilized structures including a metal wire in order to obtain improved results. Such prior art devices have involved the use of a plastic T-shaped device having a fine copper wire wrapped about the upper end of the stem of the T, a silkworm gut wrapped in a bronze wire, and a copper loop having a silkworm gut tail. These prior art intrauterine devices, however, are bulky, difficult to insert, and are not necessarily well tolerated within the uterine cavity. Moreover, whenever any beneficial effect has been observed, a substantial quantity of time has been required before such beneficial effects occur, resulting in a lag time between insertion of the device and achievement of the benefits thereof. In addition, in intrauterine devices employing a wire wrapped about a T-stem, the wire tends to dissolve and break up thus minimizing its long range effectiveness. Furthermore, such prior art devices have a relatively low surface area for the metal which, thereby, also minimizes their effectiveness. Due to these disadvantages, prior art intrauterine devices have not achieved the wide spread usage enjoyed by oral contraceptives. The present invention overcomes these disadvantages of the prior art.
SUMMARY OF THE INVENTION
An intrauterine device composite is provided which comprises a plastic matrix having a particulate material dispersed within the matrix. The particulate material is selected from the group consisting of metals and metal salts and comprises between 0.1% and 50% by weight of the composite. The particulate preferably includes both a metal and a salt, such as a sulfate thereof, although solely a metal or a salt particulate may be utilized. In addition, a radio-opaque particulate, such as barium sulfate, is preferably also dispersed within the matrix. The plastic matrix preferably has a water permeability or rate of water vapor transmission of at least 0.3 grams/100 square inches/24 hours/mil at 25° C.
BREIF DESCRIPTION OF THE DRAWING
The FIGURE is a diagrammatic illustration exemplary of an intrauterine device composite in accordance with the preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
For purposes of illustration, an intrauterine device of the type commonly termed a "shield," such as described in co-pending application, Ser. No. 775,729, filed on Nov. 14, 1968, now U.S. Pat. No. 3,633,574, generally referred to by the reference numeral 10, is shown. The shield device 10 disclosed in co-pending application, Ser. No. 775,729, preferably has a contour which conforms to the mid-range of the uterine cavity, and has a plurality of lateral fins 12--12 which promote retention and permit accommodation to uterine contractions and variations in uterine shape extending outwardly from a central membrane portion 14. As disclosed in copending application, Ser. No. 775,729, the central membrane portion 14 increases endometrial surface contact, as well as precludes bowel strangulation in the event of perforation. However, the present invention is not limited to the shield type of intrauterine device, but rather is applicable to all types of intrauterine devices, the shield type 10 only being shown and described by way of example.
Preferably, the intrauterine device 10, as shown and preferred in the FIGURE, is a composite formed of a plastic material such as a copolymer of ethylene and vinyl acetate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl chloride, nylon, or silicone rubber, such as disclosed in co-pending patent application, Ser. No. 775,729. Most preferably, the plastic material is a copolymer of ethylene and vinyl acetate, such as UE 632, manufactured by United States Industrial Chemical Corporation, which contains 13-15% vinyl acetate by weight. As shown and preferred, in addition, the plastic matrix of which the intrauterine device 10 is preferably constructed, has dispersed therein particulate material. Most preferably, the particulate is dispersed throughout the plastic matrix. The particulate material preferably includes a metal and a salt thereof, although it may comprise solely a metal or a salt. By way of example, metals which are satisfactory for purposes of the present invention are copper, zinc, silver, platinum, or cadmium. Most preferably, copper particulate is preferred. By way of example, metal salts which are satisfactory include salts of copper, zinc, silver, platinum, or cadmium. The salt is preferably a sulfate, carbonate, nitrate, acetate or phosphate. Most preferably, the salt is a sulfate of the metal particulate.
Preferably, the particulate metal in the intrauterine device composite 10 is at least 0.1% by weight of the overall composite. The metal salt is, preferably, at least 0.5% by weight of the overall composite. In addition, the preferred overall content of metal plus metal salt in the composite should not exceed 50% by weight of the overall composite, thereby providing a preferred range of total particulate, by weight, in the overall composite of between 0.1% to 50% by weight.
The requisite amount of particulate material, which is biologically active, is preferably related to the water permeability or rate of water vapor transmission of the plastic matrix, which is biologically inert. The greater the permeability of the plastic, the less the requisite amount of active particulate that need be present. Conversely, the lower the permeability, the greater the requisite amount of active particulate that should preferably by present. Preferably the water permeability or rate of water vapor transmission of the plastic is at least 0.3 grams/100 square inches/24 hours/mil at 25° C.. If desired, better results may be obtained with a water permeability of at least 5 grams/100 square inches/24 hours/mil at 25° C.. Most preferably this rate is at least 10 grams/100 square inches/24 hours/mil at 25° C..
In addition to the presence of a particulate of a metal and a salt thereof in the preferred composite, a radio-opaque particulate material may also be dispersed therein. Preferably, this radio-opaque material is a salt of an alkaline earth metal, such as barium. Most preferably, this salt is barium sulfate.
In order to form the intrauterine device composite, conventional techniques may be utilized. Once such preferred conventional technique requires intimately admixing particles of the desired plastic with finely ground particulate metal and particulate metal salts at a sufficiently high temperature for a sufficient time in order to obtain a homogeneous-like phase. The resultant impregnated plastic having the particulate material dispersed throughout is then molded under heat and pressure in a conventional manner to readily form any desired configuration such as the shield configuration 10 illustrated in the FIGURE.
The resulting intrauterine device compsite consists of a plastic matrix having the particulate material dispersed throughout the matrix. This is illustratively shown by the particulate, generally referred to by the reference numeral 16, shown in the FIGURE. Most preferably, the intrauterine device composite comprises a plastic matrix of a copolymer of ethylene and vinyl acetate having a particulate of copper and cupric sulfate dispersed throughout the matrix, with the percent by weight of the copper and cupric sulfate particulate being between 0.5% to 10% by weight of the composite, and the water permeability of the plastic being at least 10 grams/100 square inches/24 hours/mil at 25° C..
The presence in the water permeable plastic matrix of the biologically active metal particulate which preferably does not exceed an amount which degrades the plastic matrix so as to eliminate the beneficial flexibility thereof, assists the tensile strength, flowability for molding and other physical properties of the intrauterine device composite. In addition, the presence of the metal salt particulate, which is preferably a salt which is capable of relatively rapid ionization after insertion of the intrauterine device composite within the uterine cavity, is believed to ionize much more rapidly than the free metal particulate and causes rapid release of metal ions. When only a metal salt particulate is utilized, the ionization of the salt provides early protection, whereas protection at a later time is provided by the chemotactic effect of the plastic matrix. Preferably, the biologically active particulate is capable of enhancing the chemotactic effect of the otherwise relatively inert plastic material. By virtue of the "controlled release" of the biologically active particulate, relatively low concentrations thereof are capable of exerting a gameto toxic effect.
Whether the presence of the metal salt and/or metal exerts a spermicidal and/or ovacidal action or causes the tissue to react in such a manner so as to produce a material which itself is spermicidal and/or ovacidal, the presence of the metal in the ion state accelerates this action, and the rapid ionization of the metal salt enhances this result.
By utilizing an intrauterine device composite in accordance with the preferred embodiment of the present invention, the properties and capabilities of an intrauterine device are markedly enhanced.