Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2000-10-18
2002-10-01
Cain, Edward J. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C523S176000
Reexamination Certificate
active
06458886
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to pressure sensitive adhesive compositions suitable for various medical applications and especially suitable for use for adhesion to the skin. The adhesive composition may be used for securing ostomy appliances to the skin and for sealing around an ostomy, for securing wound dressings or wound drainage bandages to the skin, for securing devices for collecting urine to the skin, or for securing orthoses or prostheses to the skin. More specifically, this invention relates to adhesive compositions comprising a blockcopolymer having a major content of di-block copolymer, the use of such adhesive compositions for the preparation of a wound dressing or an adhesive wafer for an ostomy appliance, and to wound dressings or ostomy appliances comprising such adhesive composition.
BACKGROUND OF THE INVENTION
Various skin adhesive agents are used today for the above mentioned purposes.
A very widespread embodiment of skin adhesive agents comprises a self-adhesive elastomeric matrix, in which water-absorbing, swelling particles, the so-called hydrocolloids, are dispersed.
Adhesive compositions comprising hydrocolloids have been known for many years. U.S. Pat. No. 3,339,549 discloses a blend of a rubbery elastomer such as polyisobutylene and one or more water soluble or water swellable hydrocolioids such as a powdery mixture of pectin, gelatine and carboxymethylcellulose. The adhesive mass has a water-insoluble film applied to one surface. A composition of this type is available commercially from E.R. Squibb & Sons Inc. under the trademark “Stomahesive” and is used as a skin barrier around stomas to prevent skin breakdown by the corrosive fluids discharged by the stoma.
In adhesive compositions of this type, the polyisobutylene is responsible for provision of the adhesive properties and the dispersed hydrocolloid powders absorb fluid and render the adhesive agent capable of also adhering to moist skin (wet tack). These compositions are also gaining increasing acceptance as wound dressings for dermal ulcers, burns and other exuding wounds.
One major problem which has been encountered with conventional adhesive compositions comprising hydrocolloids is their susceptibility to breakdown upon exposure to body fluids. When the compositions are used as skin barriers, e.g., around stomas, absorption of fluid is desirable, but excessive swelling causes the composition to lose its integrity opening for leaks and the barrier must be replaced more often than is desirable from a skin protection point of view, and very often, a residue remains on the skin, which in many cases is difficulty to remove.
A number of attempts have been made to improve the properties of adhesive compositions in order to overcome the above-mentioned drawbacks.
In a number of embodiments, styrene copolymers have been incorporated which is disclosed in a number of patent references.
Thus, U.S. Pat. No. 4,231,369 Sorensen et al. disclose an ostomy skin barrier consisting of a styrene copolymer having dispersed therein a water soluble hydrocolloid gum and a tackifier.
In U.S. Pat. No. 4,367,732 Poulsen et al. disclose an ostomy skin barrier consisting of a water soluble hydrocolloid dispersed in a continuous phase consisting of a styrene copolymer, a hydrocarbon tackifier, and a plasticizer, an antioxidant, and an oily extender.
U.S. Pat. No. 4,551,490 (Doyle et al.) discloses medical grade pressure sensitive adhesive compositions comprising a homogeneous mixture of 5-30% of one or more polyisobutylenes, 3-20% of one or more styrene radial or block type copolymers having a content of diblock copolymer below 20%, mineral oil, one or more water soluble hydrocolloid gums, and a tackifier. One or more water swellable cohesive strengthening agents, an antioxidant, and various other optional ingredients also may be included within the adhesive composition.
U.S. Pat. No. 5,492,943 discloses a pressure sensitive adhesive composition including a blend of two viscoelastic adhesive elastomers, specifically, high molecular weight polyisobutylene and a styrene block copolymer, which along with a plasticizer (preferably petrolatum) and a suitable tackifier and antioxidant, form a continuous phase in which hydrocolloids such as sodium carboxymethy-cellulose and pectin are dispersed. The adhesive compositions disclosed in U.S. Pat. No. 5,492,943 are stated to be used for wafers for adhering ostomy appliances to the skin and differ from known compositions by comprising styrene blockcopolymers having a higher content of diblock copolymer, completely avoiding the use of low molecular weight polyisobutylene and furthermore by preferably nor including gelatine.
WO 98/17329 discloses adhesive compositions comprising below 20% of styrene copolymer having a major content of diblock copolymer and furthermore comprising a tackifying liquid constituent.
Adhesives based on three-block styrene-isoprene-styrene (SIS) copolymers are highly elastic and show a very high degree of cohesion. Traditional SIS-based adhesives are all modified using a resin and plasticizer in order to obtain a suitable balance between the plastic and elastic properties in order to obtain satisfactory adhesiveness and, at the same time, sufficient plasticity which implies that the adhesive is able adapt to the structure and follow the movements of the skin without loosing the grip.
The properties of the adhesive may be adapted shifting the composition of the copolymer which traditionally has been effected by changing the amount and type of resin and plasticizer, respectively. The block copolymer typically has been constituted by a three-block copolymer (SIS) having a minor content of diblock copolymer (Originally a “contamination” due to non-perfect polymerisation or coupling).
Now the process of polymerisation may be controlled and copolymers having different contents of diblock component may be produced, even copolymers consisting of only diblock copolymers may be made.
It has now been found that when controlling the contents of diblock component it is possible to impart new properties to the adhesive composition rendering the adhesive plastic and more adhesive which properties hitherto only have been obtainable through modification using low-molecular resins and plasticizers.
It has surprisingly been found that when using a blockcopolymer having a major content of di-block copolymer it is possible to prepare an adhesive composition for application on skin without having to rely on the addition of plasticizers normally used in connection with styrene copolymers in adhesive compositions.
Furthermore, it is possible to obtain, when using adhesives according to the invention, properties beyond those obtainable with adhesives of the state of the art.
BRIEF DESCRIPTION OF THE INVENTION
The invention relates to pressure sensitive adhesive compositions suitable for various medical applications and especially suitable for use for adhesion to the skin, the use of such adhesive compositions for the preparation of a wound dressing or an adhesive wafer for an ostomy appliance, and to wound dressings or ostomy appliances comprising such adhesive composition.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a pressure sensitive adhesive composition suitable for medical purposes comprising a blockcopolymer consisting of or having a major content of diblock copolymer, one or more water soluble or water swellable hydrocolloids and optionally a tackifier resin, said composition comprising from 10 to 60% of the total composition of a blockcopolymer comprising a monoalkenyl arene component and a conjugated diene component having a proportion of three-block copolymer to diblock copolymer from 3:1 to 1:15, from 10 to 45% of the total composition of a tackifier resin and from 20 to 65% of the total composition of one or more water soluble or water swellable hydrocolloids.
It has been found that by varying the contents of diblock copolymer fraction of the composition it is possible to tailor the properties of the adhesive without havi
Nielsen Anders Christian
Nielsen Inger Mann
Cain Edward J.
Coloplast A/S
Jacobson & Holman PLLC
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