Surgery: splint – brace – or bandage – Bandage structure
Reexamination Certificate
1999-07-08
2001-05-29
Lewis, Kim M. (Department: 3761)
Surgery: splint, brace, or bandage
Bandage structure
C602S042000, C424S449000
Reexamination Certificate
active
06238362
ABSTRACT:
The invention relates to a transdermal therapeutic system (TTS) for the delivery of active compound to or through the skin, having a layer adhering comparatively permanently to the skin, whose outer edges are defined by a contour. Below, TTS is to be understood as meaning transdermal therapeutic systems adhering to the skin either over part of the surface or over the whole surface.
A technical problem in the development of TTSs is the guarantee of a contour-sealing combination with the skin when wearing for periods of 24 hours up to 7 days or more. Contour-sealing in this connection means that detachment of an outer edge of the TTS from the skin is largely avoided.
In order to guarantee an adhesive combination of a TTS with the skin for comparatively long periods, on the one hand an optimization of the adhesive layer on the skin side is necessary. Depending on the construction of the TTS, this layer can be active compound-containing and moreover can contain pharmaceutical auxiliaries which favour the dermal permeation of the active compound. In such cases, the adhesive behaviour of the layer is affected to a greater or lesser extent by the nature and amount of the active compounds and auxiliaries contained. On the other hand, additional effects on the wearing behaviour originate from the size of the TTS and from the administration site on the human body. The mechanical forces acting on the TTS (e.g. stretching, compression and shear forces), which can lead to an at least partial detachment from the skin, substantially result from these two parameters.
The establishment of optimum adhesive properties is an object concerning the formulation of the adhesive layer, which optionally contains active compound, and depends strongly on the internal and external construction of the TTS. The variabilities associated therewith make the generalization of successful formulations largely impossible. For each new TTS, as a rule a more or less laborious optimization of the adhesive properties is therefore necessary.
However, a contour-sealing long-term application of a TTS to the skin is affected to a considerable extent by the outer shapes of a TTS in the sense of the course of its contour, which depending on its design can mechanically prevent the detachment of the outer edges of a TTS when it is worn on the skin and can thus advantageously delay it.
The fixing of the outer contour of TTSs conforms, according to the prior art, to the following criteria:
1. The production of a TTS in its final form is customarily carried out by separation from a thin-layer, strip-like material. It can be, for example, a question of punching at regular intervals with a flat punching tool or continuous cutting with a cylindrical cutting tool. In this case, the production of a contour of a TTS preferably aims at as low an amount as possible of waste during punching or cutting. This applies in particular in the case of active compound-containing waste. Since the starting material, as a rule, has a multilayer, complex construction, reutilization of the waste is often impossible or unprofitable.
The waste reduction thus has a large role among the criteria for the production of a contour in TTS production.
2. Under the aspect of decreased detachment behaviour of a TTS which is stuck to the skin, acute angles of <90° are avoided in the contour. Such tips are particularly exposed points for detachment from the skin and are avoided as a result of this. Right-angled corners are rounded, which has proved in practice to be a suitable means for reducing corner detachment and finds general application.
3. The outer shape of a TTS must produce no aversion to application and wearing on the skin for patients. It must therefore favour simple application and easy removal. Simple geometric contours have proved suitable. In the prior art, this has led to TTS contours which are defined by the shapes of the circle, the ellipse, the rectangle, the square or other polygons.
FIG. 1
shows an exemplary selection of the customary shapes.
The document U.S. Pat. No. 4,666,441 discloses a TTS whose contour contains concave sections. What is referred to here is the product “Estracombi”® from Ciba. The shape of this system, which outside technical terminology is also called a “glasses patch” is, however, not connected according to the invention with an improvement in the contour-sealing combination with the skin. On the contrary, the construction serves for a chambering of the liquid reservoir contained. The proportion of the concave contour sections in the total length of the outer TTS contour is moreover less than 10 per cent.
Outside the TTS group, other skin-adhesive systems are known whose contours in some cases include concave sections. In contrast to TTSs, these are essentially more flexible plasters or plaster-like elements such as:
wound plasters for application on the eye (e.g. U.S. Pat. No. 4,709,695).
UV protective plasters for application in the area underneath the eye (e.g. U.S. Pat. No. 4,719,909).
Skin-adhesive hydrogels for cosmetically affecting the skin condition in the area under the eye (e.g. DE 44 46 380).
Plasters to prevent the growing-in of the toenail on the big toe (e.g. DE 38 23 889).
Plasters for spreading the nasal wings and thereby improving breathing through the nose (e.g. Breath Wright™ in the USA).
It is common to all these relatively flexible skin-adhesive systems that in them the concave contour course is prespecified by individual anatomical conditions at the application site. Shaping is in this way tailored to the human anatomy.
REFERENCES:
patent: 4666441 (1987-05-01), Andriola et al.
patent: 4709695 (1987-12-01), Kohn et al.
patent: 4719909 (1988-01-01), Micchia et al.
Hochberg D. Peter
Holt William H.
Lewis Kim M.
LTS Lohmann Therapie-Systeme AG
Vieyra Katherine R.
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