Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Web – sheet or filament bases; compositions of bandages; or...
Reexamination Certificate
1999-12-28
2004-02-10
Jones, Dameron L. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Web, sheet or filament bases; compositions of bandages; or...
C536S123000, C424S400000, C424S401000
Reexamination Certificate
active
06689378
ABSTRACT:
TECHNICAL FIELD
The invention relates to the incorporation of cyclodextrin into articles containing polysaccharides. More specifically the present invention relates to methods of immobilizing cyclodextrin onto cellulose fibers, to cellulose fibers having cyclodextrin immobilized thereon, and to articles made from such fibers.
BACKGROUND OF THE INVENTION
Numerous attempts have been made to conceal odors through the use of perfumes. Not only are such perfumes often inadequate at fully concealing odors, very often they are irritating to a user's skin. Additionally, the perfume odor itself may be irritating or offensive to a user's respiratory system and/or olfactory senses, as well as to nearby individuals.
Attempts have also been made to control odors through the use of odor absorbents. Zeolites such as those marketed under the name ABSCENTS® by Union Carbide Corporation and UOP LLC are known odor absorbers. However these solid odor absorbers, as well as activated charcoal odor absorbers, lose functionality when wet. Therefore, these odor absorbers are not preferred for applications where the article is likely to be wetted by body fluids as they lose their desired odor absorbent characteristics. Furthermore, zeolites can cause a “harsh” feel if too much is deposited onto the skin.
Cyclodextrins have been used as both perfume releasers and as odor absorbents. U.S. Pat. No. 5,660,845 to Trinh et al., for example, discloses a cyclodextrin powder useful for incorporation into an article, such as a fabric treatment sheet. U.S. Pat. No. 5,783,552 to Trinh et al., for example, discloses uncomplexed cyclodextrins incorporated into an article in the form of particles or releaseably attached to a substrate, for odor absorption.
Cyclodextrins are cyclic carbohydrates that can be produced enzymatically from starch, are generally safe for humans, and are non-polluting. In general, cyclodextrins include glucose units arranged in a donut-shaped ring. The specific coupling and conformation of the glucose units give the cyclodextrins a rigid, conical molecular structure with a hollow interior of a specific volume. Cyclodextrins thus offer a toroidal geometry with a hydrophilic exterior, which allows the cyclodextrin to dissolve in water. The “lining” of the internal cavity is formed by hydrogen atoms and glycosidic bridging oxygen atoms. This interior surface, therefore, is fairly hydrophobic.
Cyclodextrins have useful chemical properties often tied to the inclusion of chemicals in the toroidal cavity. This cavity can be filled with all or a portion of an organic molecule with suitable size to form an “inclusion complex.” The association of the molecule with the cyclodextrin isolates the molecule from the aqueous solvent and may increase the molecule's stability and water solubility, since the solubility of the cyclodextrin is often higher than the solubility of the molecule. Accordingly, cyclodextrins can be used to releaseably complex chemicals, such as perfumes, drugs, flavors, insecticides, odor-mitigating chemicals, skin wellness compounds, and the like.
The unique shape and physical-chemical properties of the cavity also enable cyclodextrin molecules to absorb (form inclusion complexes with) organic molecules or parts of organic molecules which can fit into the cavity. Many odorous molecules can fit into the cavity including many malodorous molecules and perfume molecules. Therefore, cyclodextrins, and especially mixtures of cyclodextrins with different size cavities, can be used to control odors caused by a broad spectrum of organic odoriferous materials, which may or may not contain reactive functional groups.
Cyclodextrin complexes have been added to cellulose-containing articles for various purposes, as described in the above referenced patents to Trinh et al. Cyclodextrin complexes have been added to such articles in the form of particles or as loose powder, which may be suitable for articles, such as fabric treatment sheets, where it is desirable for the cyclodextrin complexes to be in free form. However, when used in articles such as diapers, such particles and powders may shift away from the preferred location of the article (where it is likely to become wet) and move to areas where they are less effective for their intended purpose. This problem was addressed in U.S. Pat. No. 5,733,272 to Brunner et al. by the use of an “adhesive”, in particular a water soluble binder such as polyethylene glycol (PEG), to attach the cyclodextrin/perfume complex to the moisture-receiving area of the article. However, immobilization of cyclodextrin complexes remains a problem.
Another problem with use of cyclodextrin complexes is that they can be solubilized by aqueous solutions contacting the article and be “washed” away.
It is known to derivitize cyclodextrin with reactive moieties that can in turn react with a fabric or other substrate. Particular examples known in the art include cyclodextrin reacted with epicholohydrin and chlorinated or fluorinated triazinyl compounds, which can subsequently react with cellulose. These methods typically require pretreatment of the cyclodextrin before it can be combined with cellulose, and also suffer from safety, environmental, and high reactivity issues associated with the halogenated reactants (typically chlorinated reactants).
Accordingly, what is needed is improved methods of immobilizing cyclodextrin to cellulose. What is also needed are compositions including cyclodextrins immobilized to cellulose fibers.
SUMMARY OF THE INVENTION
The present invention is directed to methods of immobilizing uncomplexed cyclodextrins and complexed cyclodextrins to polysaccharide containing substrates, such as cellulose fibers. The present invention is also directed to compositions including cyclodextrin immobilized to a substrate, such as, preferably, one containing cellulose fibers. The cyclodextrins are immobilized by covalently bonding the cyclodextrin to the substrate, without having to first derivatize or otherwise modify the cyclodextrin. The cellulose/cyclodextrin compositions can be used in all types of cellulose fiber containing articles, such as tissues and personal care articles.
In one embodiment, the compositions contain uncomplexed cyclodextrins that function as capture agents for capture of pollutants and undesired hydrophobic agents. These compositions can function for odor control, for example. In another embodiment, the compositions include complexed cyclodextrins which function as release agents for release of, for example, perfumes or other active ingredients. Such compositions can also be used for controlled delivery of pharmaceutical agents and other chemicals from the cyclodextrin to a localized area, such as with a transdermal patch.
The means of covalently bonding the cyclodextrin to the polysaccharide can comprise a crosslinking agent capable of forming an ester or hemiacetal bond with the cyclodextrin, wherein the agent desirably is chlorine free or halogen free, or, more generally, lacks a reactive halogen group. The ester or hemiacetal bond to the cyclodextrin may be formed directly with the polysaccharide, or may be formed with a polymer which in turn is bonded to the polysaccharide, preferably through another ester or hemiacetal bond. In particular, the crosslinking agent can include a polycarboxylic acid or polymer comprising multiple cyclic anhydride groups, either of which can form ester bonds between cyclodextrin and cellulose, typically in the presence of a catalyst and suitable conditions of pH and temperature. The crosslinking means can alternatively comprise added aldehyde groups on the polysaccharide, particularly dialdehyde groups, formed by oxidation of the polysaccharide prior to reaction with cyclodextrin. The aldehyde groups can react with a hydroxy group on cyclodextrin in acidic conditions to form a hemiacetal bond. Desirably, the crosslinking means enables the cyclodextrin to be covalently bonded to the polysaccharide without the need for derivitizing the cyclodextrin (specifically, without the need to add rea
Lindsay Jeffrey D.
Sun Tong
Jones Dameron L.
Kimberly--Clark Worldwide, Inc.
Pauley Petersen & Erickson
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