Coating processes – Medical or dental purpose product; parts; subcombinations;... – Flexible web – sheet – film – or filament base
Reexamination Certificate
1997-09-22
2001-01-23
Dudash, Diana (Department: 1762)
Coating processes
Medical or dental purpose product; parts; subcombinations;...
Flexible web, sheet, film, or filament base
C118S025000, C118S325000, C118S612000, C222S486000, C427S002120, C427S002130, C427S394000, C427S420000, C604S368000
Reexamination Certificate
active
06177126
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a process for the production of a material for sealing and/or healing wounds which comprises the even application of a liquid composition to a suitable carrier.
A material for sealing and healing wounds which comprises a collagen carrier, coated with a fibrinogen component, a thrombin component and possible additional components is known from U.S. Pat. No. 4,453,939.
To prepare a material of this kind, a fibrinogen component, a thrombin component and possible additives are suspended in an organic solvent, e.g. ethanol, and subsequently applied to a suitable carrier, e.g. by means of spraying.
In spraying such a suspension containing a fibrinogen component and a thrombin component on the carrier, several problems arise, because the suspension to be applied is difficult to handle. For example, the nozzles usually used for these purposes clog immediately. Air atomizing nozzles permit the use of a larger diameter, but even in this case, only nozzles with the largest diameter available allow working with a sufficient lack of trouble. However, these nozzles show a fatal disadvantage. The indistinct definition of the exiting stream does not result in an application of an even layer of the suspension, but creates a trapezoidal coating profile on the carrier. This leads to considerable losses of valuable and expensive suspension and of carrier material at the edges.
A device for applying a liquid film to a fabric web according to the pouring-out principle is known from EP-A 472 050. By means of individual partitions for liquid which are located directly next to one another, this device achieves a forced distribution of the liquid from a feed opening to a number of outflow openings. The liquid is distributed in the form of a family tree, i.e step by step from one opening to two, four, eight, sixteen, etc. outflow openings. Such a device is not suitable for an even distribution of a suspension containing fibrinogen and thrombin components, as the several divisions of the liquid stream cause conglutination and clogging of the partitions by the suspension. Furthermore, such a conglutination and clogging occurs to a greater extent than when nozzles are used.
SUMMARY OF THE INVENTION
The problem solved by the present invention is therefore to substantially reduce or preferably prevent the disadvantages of the previously known methods. Especially, the present inventors have focused on reducing and/or avoiding the disadvantages of the known methods with respect to i) the considerable loss of very expensive material and to ii) separation of the components contained in the suspension during application of the suspension on the carrier; the latter disadvantage has also shown to be dependent on variations of the suspension (e.g. with respect to temperature, viscosity, composition etc.). All these problems have been realized with the known methods.
An object of the present invention is therefore a process for the production of a material for sealing and/or healing wounds, comprising:
i) filling a liquid composition into a container having two or more plates, at least two of the plates being perforated with one or more flow-through holes and at least one of the perforated plates being movable relative to another of the perforated plates,
ii) transporting a suitable carrier below the container in a transport direction, and
iii) continuously moving the perforated plates relative to each other so as to allow the liquid composition to drip on to the carrier being transported below the container,
whereby the liquid composition is substantially evenly applied to the carrier.
Although the process according to the invention in particular is useful when a suspension is to be applied on a carrier, the novel process is also suitable for the application of any liquid composition. The process involves the use of a device which enables adjustment of how and how fast a liquid composition is applied on a carrier, and such adjustment measures enable a more general applicability than just for liquid compositions in the form of a suspension. In the present context the term “liquid composition” therefore covers suspensions as well as solutions, mixtures, dispersions, emulsions, and lotions.
A novel device is also an object of the present invention, namely a device for even application of a liquid composition to a carrier for the production of a material for sealing and healing wounds. The device comprises a container into which the liquid composition is filled and which has a base frame and two perforated plates forming a bottom of the container, the two perforated plates including an upper plate and a lower plate, the plates being movable relative to each other so as to allow a continuous back and forth movement of the upper plate, whereby the liquid composition is evenly applied to the carrier, the carrier being transported below the device in a transport direction.
In a more specific embodiment, the invention relates to a process for the production of a material for sealing and/or healing wounds, comprising:
i) filling a suspension into an elongated container, the elongated container having a base frame and two perforated plates forming a bottom of the elongated container, the two perforated plates including an upper plate and a lower plate, the upper plate being movable relative to the lower plate,
ii) transporting a carrier below the elongated container in a transport direction, and
iii) continuously moving the upper plate back and forth so as to allow the suspension to drip on to the carrier being transported below the elongated container,
whereby the suspension is substantially evenly applied to the carrier.
In still another embodiment the invention relates to a process for the production of a material for sealing and healing wounds which comprises the even application of a suspension to a suitable carrier, characterized in that the elongated container, into which the suspension is filled, is provided with a base which allows the suspension to drip on the carrier which is transported underneath the container. The drops are guided by e.g., a sharp cannula or a needle.
The invention also relates to a method for healing and/or sealing wounds comprising applying on the wound a material prepared as in the process of the present invention.
Furthermore, the invention relates to a method for stopping oozing blood from wounds comprising applying on the wound a material prepared as claimed in the process of the present invention.
It is important to note that a process according to the present invention is not limited to the preparation of a wound healing and/or sealing material. The process is generally applicable and especially useful for the preparation of biocompatible material for use in, e.g., surgery or minimally invasive surgery and for use in other circumstances where healing and/or sealing of a wound is required. The composition contained on a biocompatible carrier is effective as, e.g., healing and/or sealing wounds but the invention is not limited to a process for the preparation of such a material within the scope of the invention is also a process for the preparation of biocompatible material wherein the composition applied on the carrier also may contain other drug substance(s) useful in therapy (e.g. anti-inflammatory agents, antiviral agents, anti-infective agents, growth factors, etc.) optionally in combination with an agent for healing and/or sealing wounds.
Suitable carrier materials for use in a process according to the invention are biocompatible materials. The carrier (i.e. the carrier material) may be bio-degradable or self-dissolving materials like collagen, gelatin, oxidized cellulose, polyglycolic acid, polylactic acid, polyhydroxybutyric acid in non-woven and woven form or non-degradable materials like polyethylene, polypropylene, polyamide, polyester, polypropyxypolyamide, polyurethane in non-woven and woven form. Among the degradable materials, collagen is the preferred material. Foam is the most preferred form of polyurethane.
A material f
Hagedorn Olaf
Schiele Ulrich
Dudash Diana
Nycomed Arzneimittel GmbH
Wenderoth , Lind & Ponack, L.L.P.
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