DK148408B - MEDICAL CLAIMS - Google Patents

Description

148408 i

The invention relates to medical adhesives containing synthetic rubber, filler and plasticizer.

More particularly, it relates to an adhesive which, among other things, can be used to adhere aids to an animal body.

It is often necessary to provide an adhesive connection to an animal body, usually the human body, to attach a medical aid or apparatus. Although many adhesives are known, very few of these are suitable for use on human skin. The requirements for such an adhesive are strict; it must bind strongly to human skin, but could be pulled off without damaging the skin surface. Furthermore, it should not cause inflammation, even during prolonged contact, and it should have a minimal tendency to cause 15 allergies. It must be free from any substance which may be carcinogenic. The requirement that it should not cause allergies is particularly difficult to meet, and most of the available adhesives tend to cause allergies in a significant proportion of patients.

20 When the patient is prone to allergies, it may be necessary to try a number of adhesives before finding one that is compatible. This is time-consuming for the physician, and in the meantime, the patient is exposed to discomfort due to allergic reactions.

25 It is from GB Patent No. 554,186 and no.

585,184 are commonly known to use blends of synthetic rubber, filler, plasticizer and resin as medical adhesives, and additionally, it is well known to use polyalkyl acrylate resins in medical drugs.

However, as mentioned, such adhesives have been found to tend to cause allergies in a significant proportion of patients.

From U.S. Patent No. 3,092,250, it is known to produce pressure-sensitive adhesives containing chlorinated rubber and acrylate ester polymer. These adhesives are used for making adhesive tapes used for technical purposes e.g. sound and vibration attenuation in aircraft.

The object of the invention is to provide a medical adhesive having "the advantage of not adhering in the presence of water, having a good adhesion and being completely free of allergenic effects.

This is achieved according to the invention with a medical adhesive containing synthetic rubber, filler and plasticizer which is characterized in that it consists of a gelled mixture of: a) 16 - 84 g of polyethyl methacrylate, b) 100 ml of butyl-phthalyl-butyl glycollate or butylbenzyl phthalate, c) 6-16 g of colloidal silica, and d) 16-67 g of chlorinated polyisoprene.

The polyethyl methacrylate is a brittle solid which preferably has a molecular weight in the range 50,000-20,000,000, more preferably in the range 100,000-500,000, e.g. ca. 200,000.

Butyl-phthalyl-butyl-glycollate or butyl-benzyl-phthalate is a softening component. This is a physiologically tolerable liquid which serves to soften the polyethyl methacrylate. Butyl phthalyl butyl glycollate and butyl benzyl phthalate are available from Monsanto as "Santicizer ® B16" and "Santicizer ® 160" respectively.

These plasticizers are physically compatible with the other components of the agent and are physiologically tolerable, including non-allergenic.

Colloidal silica is an inert particulate filler which serves to stabilize the agent in the form of a coherent gel. The filler also reduces the tackiness of the agent, and the amount and nature of the filler must be selected so as to produce the required degree of tackiness. Without filler, the adhesive is very strong and the adhesion to the human skin is difficult to break without damaging the skin.

5 The chlorinated polyisoprene improves the tackiness and cohesiveness of the agent. Preferred chlorinated polyisoprene types are highly chlorinated polyisoprene, such as the highly chlorinated polyisoprene available from Imperial Chemical Industries as "Alloprene® 20". 100 ml of butyl-phthalyl-butyl-glycollate or butyl-benzyl-phthalate according to the invention as follows: Polyethylmethacrylate 16-84 g, preferably 20-45 g, silica 6-16 g, preferably 8-12 g, and chlorinated gums 16-67 g, 15 preferably 20-40 g. The relative proportions of the amounts must be adjusted within these ranges to obtain products having the desired properties. The optimum interrelationships for achieving any particularly desired combination of properties can be determined by simple experiments.

The agent can be prepared by dispersing and dissolving the polyethyl methacrylate, in powder form, in the plasticizer to form a gel. The filler and chlorinated rubber can be added at any stage, preferably while the viscosity is still low enough to allow a thorough mixing. In a preferred mixing method, the filler is mixed with the plasticizer to which the polyethyl methacrylate is added and finally the chlorinated rubber is added.

Initially, the mixture is a rigid paste which is converted to a homogeneous gel as the plasticizer dissolves the polyethyl methacrylate. This conversion proceeds slowly at room temperature and is accelerated by heating, e.g. to 40-80 ° C. Higher or lower temperatures can be used where convenient. At 60 ° C, conversion 4

1484O S

the latter typically ends in 4-5 hours. The conversion time depends to a large extent on how finely divided the polyethyl methacrylate is. Preferably, this material is used in the form of a powder in the range 50-400 mesh (British Standard Sieve), preferably below 200 mesh.

After the transformation, the agent is a semi-transparent flexible gel with a rubbery texture and it feels sticky. It has good adhesion to human skin, but is easily removable. The material is stable, ie. it becomes cohesive, does not flow out, and has a high concentration of filler and retains its tackiness and adhesiveness after prolonged storage and use.

It is often convenient to transfer the gel in situ to the gel on the surface which must be made adhesive.

Alternatively, prior to conversion, the agent may be spread on a surface of a release agent and transferred in a gel state in the form of a layer which may then be laminated to the article to be adhered. Another way of applying the agent is to form a dispersion of the agent 20 in an organic solvent which dissolves all the components of the agent except the filler, e.g. a chlorinated hydrocarbon, such as chloroform or ethylene dichloride, apply the dispersion to an article to be adhered and evaporate the solvent. Other suitable solvents are lower aliphatic ketones, e.g. acetone, aliphatic ethers, e.g. diethyl ether, and lower alkanols, e.g. ethanol. Often, it is preferred to avoid using a solvent, as some patients exhibit allergic reactions to common organic solvents. Therefore, it may be advantageous to select the agent in paste form into a thin layer between surfaces with a coating-acting coating and to apply the agent to the article to be adhered either before or after conversion of the mixture to a 35 gel.

148408 5

The agent has a wide application as an adhesive, especially but not exclusively for use on human skin, e.g. as adhesive coatings on adhesive tapes for surgical use and other medical and surgical dressings, covers and aids. Such a surgical adhesive bandage or bandage will comprise a flexible substrate which carries the present adhesive on one face. The substrate may be a substance or a plastic film, especially a microporous plastic film. When a compound with an active drug is required, such can be incorporated into the adhesive. Examples of such drugs include antibiotics, antiseptics, coal tar derivatives (which are valuable in certain dermatological disorders) and anti-inflammatory compounds, e.g. steroids. Such dressings can be used to cover wounds or other damaged skin areas, e.g. leg ulcers such as varicose ulcers. For such applications, the adhesive has the advantage of not sticking in the presence of water. Therefore, if a dressing is used to cover a damaged or fluid area of the skin, it will not adhere to the damaged area, but will only adhere to undamaged skin around it.

A particularly advantageous application of the present adhesive is to attach an ostomy bag to the skin around the stoma of a patient. After an ostomy operation, e.g. ileostomy, colostomy or ureterostomy, the patient has an opening through which a discharge occurs. The depleted is collected in a bag which is replaced periodically. There have been considerable difficulties in securing the bag's attachment to the patient in a comfortable but tight manner.

An application of the adhesive according to the invention is described below with reference to the drawing, which illustrates an adhesive element provided with adhesive according to the invention shown in cross section.

In the drawing, 1 denotes the abdominal wall of a patient, who is surgically fitted with a stoma 2. The adhesive member comprises a disc 3 of plastic with a central opening 4. The opening 4 is surrounded by 2 concentric webs 5 and 6 forming a gutter containing a ring of karaya rubber 7. The outer part of the disc is attached to the abdomen wall with a layer of adhesive 8 according to the invention with the composition given below. The second surface 9 of the disc 10 is provided for affixing a bag suitable for the discharge to be collected.

The adhesive extends slightly beyond the disc 3 to keep the device in good contact with the abdominal wall.

The composition of the adhesive is e.g. as follows, parts referring to ml for liquids and g for solids:

Example 1

Butyl-phthalyl-butyl-glycolate 6 parts 20 Polyethyl methacrylate 2 parts "Alloprene®20" 2 parts

Colloidal silica 0.65 parts

The butyl phthalyl butyl glycolate is available from Monsanto as "Santicizer ® B16". Moreover, it can be prepared by standard esterification methods.

The polyethyl methacrylate was in the form of a powder having a particle size of less than 240 mesh (British standard sieve) and had an average molecular weight of approx.

200,000. It was purchased from ADI Plastics Limited, Mar-30 ton, Blackpool, England.

"Alloprene®20" is a chlorinated polyisoprene available from Imperial Chemical Industries (Alloprene Section), Runcorn, Cheshire, England.

The silica was pharmaceutical grade with a low iron content.

First, the silica was mixed with butyl-phthalyl-butyl glycolate, and the polyethyl methacrylate and "Alloprene" were then added sequentially. A very viscous paste appeared which was mixed mechanically. The paste 5 was then rolled between two layers of silicone coated paper sheets to a thickness of approx. 1.5 mm and allowed to convert for 6 hours in an oven at 60 ° C.

Example 2

Another adhesive composition is as follows: 10 Butyl benzyl phthalate 6 ml

Polyethyl methacrylate 2 g "Alloprene ® 20" 2 g

Colloid silica 0.5 g

The polyethyl methacrylate was the same as used in Example 1. The mixing and conversion procedure was also as in Example 1.

Example 3

A third adhesive composition is as follows: Butyl phthalyl butyl glycolate 100 ml Polyethyl methacrylate 42 g Allopren® 33 g

Colloid silica 8 g

The mixing and conversion procedure was also in this case as in Example 1.

After cooling, the adhesives were present in the three samples as a coherent, highly adhesive layer that could be cut to the desired size and shape. These adhesives are extremely well tolerated by the human body. In fact, no adverse reaction has been observed so far to them even in patients who are allergic to many common medical adhesives.

The adhesives have good flow properties, as mentioned, are solid, but still "flow" well into scars and skin folds.