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Title:
SILICONE GEL ADHESIVES WITH ORGANIC POLYHYDROXY COMPOUNDS
Document Type and Number:
WIPO Patent Application WO/2012/003028
Kind Code:
A1
Abstract:
A biocompatible pressure sensitive adhesive comprising a silicone gel, and a low molecular weight, organic, hydroxy containing compound. A medical device comprising the biocompatible pressure sensitive adhesive for securing the device to a mammalian body.

Inventors:
SAMBASIVAM, Mahesh (100 Headquarters Park Drive, Skillman, New Jersey, 08558, US)
LEAR, Stephanie (28 Clump Road, Telford, Pennsylvania, 18969, US)
Application Number:
US2011/032302
Publication Date:
January 05, 2012
Filing Date:
April 13, 2011
Export Citation:
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Assignee:
CONVATEC TECHNOLOGIES INC. (3993 Howard Hughes Parkway, Suite 250Las Vegas, Nevada, 89169-6754, US)
SAMBASIVAM, Mahesh (100 Headquarters Park Drive, Skillman, New Jersey, 08558, US)
LEAR, Stephanie (28 Clump Road, Telford, Pennsylvania, 18969, US)
International Classes:
C08G63/48
Attorney, Agent or Firm:
KRIEGER, Stuart et al. (100 Headquarters Park Drive, Skillman, New Jersey, 08558, US)
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Claims:
Claims:

A biocompatible pressure sensitive adhesive comprising a silicone gel, said gel being formed utilizing a curing catalyst, and a low molecular weight, organic, hydroxy containing compound that does not affect the cure of the gel.

The biocompatible adhesive according to Claim 1 , wherein the adhesive is comfortably removed from human skin.

The biocompatible adhesive according to Claim 1 , wherein the adhesive has a peel strength of 0.5 -10.0 N/in against stainless steel.

The biocompatible adhesive according to Claim 1 , wherein the low molecular weight, organic, hydroxy containing compound has at least 3 or more hydroxyl groups.

The biocompatible adhesive according to Claim 1 , wherein the low molecular weight, organic, hydroxy containing compound is at least partially soluble in water.

The biocompatible adhesive according to Claim 1 , wherein the low molecular weight, organic, hydroxy containing compound is a non-volatile compound.

A medical device comprising a biocompatible pressure sensitive adhesive for securing the device to a mammalian body, wherein the adhesive comprises a silicone gel, said gel being formed utilizing a curing catalyst, and a low molecular weight organic hydroxyl containing compound that does not affect the cure of the gel.

Description:
SILICONE GEL ADHESIVES WITH ORGANIC POLYHYDROXY COMPOUNDS

Background

Pressure sensitive silicone adhesives are used in transdermal drug delivery, wound dressings, scar dressings, and other healthcare applications. These adhesives are typically a condensation product of silicate resin and polydimethylsiloxane (PDMS) fluid, or a reactive blend of vinyl- and hydride-containing PDMS cured via hydrosilylation reaction. These adhesives are biocompatible and securely attach medical devices to the body when the environment is dry. However, under moist conditions such as during skin perspiration, the hydrophobic silicone adhesives lose their adhesion to skin, which can lead to the device detaching from the body prematurely.

Traditionally, adhesion under moist environment in skin adhesives have been accomplished by adding water absorbing fillers such as hydrocolloids to pressure sensitive adhesives. The hydrocolloid fillers absorb moisture and soften, providing wet tack, thereby maintaining adhesion to skin for a longer period. However, the disadvantages of this approach are the reduction in the adhesive properties such as peel strength and tack due to the presence of hard fillers. In addition, because of the affinity of the fillers for water, they swell and dissolve, and leach out of the adhesive, which can leave a slimy residue on the skin after the device or dressing removal.

There is a need to improve the adhesion of silicone adhesives under moist environment and to overcome the drawbacks of previous approaches.

Prior Art

EP 1206290B1 describes a pressure sensitive adhesive comprising cylcodextrin and a hydrocolloid. The purpose of the cyclodextrin and hydrocolloid is for absorption of odor and moisture.

US 2009/0062467A1 describes a pressure sensitive adhesive comprising a polyrotaxane molecule with reactive group and a linear molecule passing through the cavity in the polyrotaxane molecule, wherein the reactive group in the polyrotaxane is reacted with the reactive groups in the adhesive polymer, which is a polyacrylate.

EP0644746 describes the use of glycerine to moderate the intial burst of drug delivered transmucosally or transdermally. The drug is delivered via a gel, paste or lotion

composition.

Description of Invention:

According to the present invention, a biocompatible pressure sensitive adhesive comprises a silicone gel formed utilizing a curing catalyst, and a low molecular weight, organic, hydroxy containing compound that does not affect the cure of the gel. This biocompatible adhesive is comfortably removed from human skin. Furthermore, this biocompatible adhesive has a peel strength of 0.5 -10.0 N/in on stainless steel. The low molecular weight, organic, hydroxy containing compound is non-volatile, and at least partially soluble in water, and has at least 3 or more hydroxy groups.

Furthermore, the invention relates to a medical device comprising a biocompatible pressure sensitive adhesive for securing the device to a mammalian body, wherein the adhesive comprises a silicone gel, formed utilizing a curing catalyst, and a low molecular weight organic hydroxyl containing compound that does not affect the cure of the gel.

Examples of low molecular weight, organic, hydroxyl containing compounds are cylcodextrin, glycerine, sorbitol, polyether polyols, etc.

Experimental details:

A small plastic cup was filled with 10g each of silicone adhesive Part A and Part B. To the silicone adhesive mixture was added the desired amount of additive as shown in Table 2. Then the contents of the cup were mixed together and degassed. The mixture was then coated onto Medifilm 428 (Mylan Technologies) with a Gardner coater set at 5 mils and then placed in the oven for 30 minutes at 150C. If solvent was used, the Gardner coater was set at 10 mils and allowed to dry for 15 minutes in a fume hood before curing in the oven at 150C. For samples containing glycerine, a small plastic cup was filled with 10g of silicone adhesive Part A and the desired amount of glycerine as shown in Table 2, mixed together, and then 10g of silicone adhesive Part B was added and mixed into the sample. The sample was then degassed and coated onto Medifilm 428 with the Gardner coater set at 5 mils. It was then cured in the oven for 30 minutes at 150C. All coated samples were then cooled and the adhesive surface was protected with a fluorinated PET liner. Note: Na- CMC was used with and without oven-drying, while Beta-Cyclodextrin was used after oven- drying. Oven drying was carried at 1 10C under vacuum for two hours.

Adhesive testing

1 . Stainless Steel (SS) Peel Test

Peel test was performed using the procedure described in ASTM D3330 Part A on 4 inch by 1 inch sized strips of coated adhesive samples. The results are shown in Table 3.

2. Moisture Vapor Transmission Rate (MVTR)

Select samples, based on the peel strength test results, were tested for MVTR. The procedure followed for this test was ASTM E98-00, with the oven set at 37C and with ambient humidity. The results are shown in Table 4.

Table 1. Description of adhesive ingredients

silsesquioxane (T8 resin) SST- H8HS8

Carbowax(TM) Sentry (TM) The Dow Chemical Polyethylene glycol 300 NF Company

NM = Not measured

Residue rating: A - no residue; B - slight residue; C - lot of residue

Results:

From the peel test results in Table 2, it can be seen that as the cyclodextrin amount is increased in the adhesive from 0% to 50%, the SS peel strength increases compared to the Control. Even a similar effect is seen with Na-CMC. Also seen from the results is that when the Na-CMC is dried before added to the sample, the peel test decreases in peel strength but doesn't leave behind residue compared to the sample of non-dried Na-CMC. Similarly, as the amount of glycerine is increased in the gel adhesive, the SS peel strength increases. At 50% cyclodextrin the MVTR decreases significantly. Na-CMC sample appears to have increased the MVTR value compared to the control sample. It should also be noted that with hydrophilic polymers such as Na- CMC, the polymer dissolves during perspiration on the skin and could leach out which is not desirable. Even though the MVTR of compositions with cyclodextrin and glycerine are not significantly higher then the Control, wear test studies show that the adhesion under moist environment is acceptable and more importantly, it does not leave a residue on skin unlike Na-CMC based compositions.