Colloid systems and wetting agents; subcombinations thereof; pro – Continuous liquid or supercritical phase: colloid systems;... – Aqueous continuous liquid phase and discontinuous phase...
Reexamination Certificate
1999-01-29
2001-06-26
Alexander, Lyle A. (Department: 1743)
Colloid systems and wetting agents; subcombinations thereof; pro
Continuous liquid or supercritical phase: colloid systems;...
Aqueous continuous liquid phase and discontinuous phase...
C536S020000
Reexamination Certificate
active
06251959
ABSTRACT:
SPECIFICATION
Chitin derivatives having carboxyalkyl groups as hydrophilic substituents and alkyl groups as hydrophobic substituents, and polymer micellar carriers comprised of these chitin derivatives, and micelle-like aqueous compositions of these chitin derivatives
TECHNICAL FIELDS
This invention relates to chitin derivatives having carboxyalkyl groups as hydrophilic substituents and alkyl groups as hydrophobic substituents, micelle-forming substances and polymer micellar carriers comprised of the said chitin derivatives, and micelle-like aqueous compositions using the said micelle-forming substances and polymer micellar carriers. In more detail, this invention relates to the chitin derivatives having carboxyalkyl groups as hydrophilic substituents and alkyl groups as hydrophobic substituents, which are useful as soil-improving agents, protein aggregating agents, micelle-forming agents, etc. In addition, this invention relates to micelle-forming substances and polymer micellar carriers, which are comprised of the chitin derivatives having carboxyalkyl groups as hydrophilic substituents and alkyl groups as hydrophobic substituents, and micelle-like aqueous compositions comprising the said chitin derivatives.
PRIOR ART
Chitin is a polymer of N-acetylglucosamine (poly &bgr;-1,4-N-acetyl glucosamine). In general, chitin is a polysaccharide comprising crustacean shells, squid pens and so on. For instance, in the processing of the crab, a lot of shells are produced as a byproduct and chitin contents of the shell is about 15% of the shell weight. Therefore, profitable utilization of chitin has been desired. Chitin is a biodegradable polymer and is very compatible to the living body, so chitin is a noteworthy material as the sutures and a wound-covering agent in the field of surgery, and also is remarkable as a disintegrable or degradable material by microorganisms. Chitin and chitosan are dietary fibers when ingested in the intestine and they are safe for a human. The average molecular weight of those generally used in food is 400,000 to 2,000,000 or more.
The molecular weight of chitin is adjusted according to the purpose of use. In general, strong acidic reagents are most in use to prepare lower molecular weight chitin. The example as follow: the crab chitin which average molecular weight is about four hundred thousands is warmed with 5-10% hydrochloric acid and washed with water and neutralized. Then that is treated with 10-20% sodium hydroxide at 60-90° C. to remove proteins and washed with water, neutralized and dried. Finally, the low molecular weight chitin which have 100,000 or less molecular weight is obtained. Other methods for preparation of the lower molecular weight chitin include the treatment with alkaline solutions, peracids, hydrochloric acid, acetic acid, propionic acid, lactic acid, ascorbic acid and also the enzymatic treatment, such as chitinases (derived from microorganisms and plants) and lysozymes.
Chitin and its derivatives have been used as soil-improving agents, protein aggregating agents and wood-improving agents. And it has been reported that the polymer structure having both hydrophilic and hydrophobic moieties showed desirable property in micelle-formation and that polymer can solubilize the hydrophobic compound. However, there has been no report on the nature of the carboxyalkyl chitin derivatives and the method of production thereof.
In addition it is known that carboxymethylated chitin is more potent in activation of macrophages than the sulfated chitin.
For example, there is a description of the immunological activity of chitin derivatives on pages 195 to 197 of “Application of Chitin and Chitosan” 1
st
Edition 1
st
Print on Feb. 20, 1990, edited by the Japanese Society for Chitin and Chitosan, and published by GIHODO Publishing Co. Various immunologic properties, such as immunity-enhancing activity, anti-tumor activity and infection-resistance-increasing activity, of chitin derivatives were investigated to develop immunity-enhancing agents and/or medical materials from chitin derivatives. It is described that the 70%-deacetylated chitin (DAC-70) had a marked macrophage-activating potency, and the chitin derivative having carboxymethyl group had a comparable potency to that of DAC-70, while the chitin derivative having sulfate group was inactive.
DISCLOSURE OF THE INVENTION
The purpose of this invention is to provide chitin derivatives having carboxyalkyl groups as hydrophilic substituents and alkyl groups as hydrophobic substituents, which are useful for production of soil-improving agents, protein aggregating agents, micelle-forming agents, etc. The purpose of this invention is to provide micelle-forming substances comprised of the said chitin derivatives. The purpose of this invention is to provide polymer micellar carriers comprised of the said chitin derivatives. The purpose of this invention is to provide aqueous micelle-like compositions using the chitin derivatives having carboxyalkyl groups as hydrophilic substituents and alkyl groups as hydrophobic substituents as the polymer micellar carriers.
The gist of this invention is chitin derivatives having carboxyalkyl groups represented by the formula (1) below.
[wherein, R
1
stands for either an alkyl group represented by (CH
2
)
n
CH
3
with n=1 to 20, an alkylcarbonyl group represented by CO(CH
2
)
n
CH
3
with n=1 to 19, a carboxyalkyl group represented by (CH
2
)
n
COOH with n=1 to 5 or a salt thereof, H, or COCH
3
, and R
2
stands for a carboxyalkyl group represented by (CH
2
)
n
COOH with n=1 to 5 or a salt thereof or H; the degree of deacetylation of the N-acetyl group in chitin is 70 to 100% (100% deacetylation means one deacetylated N-acetyl group per one monosaccharide unit); the degree of substitution of R
1
with one of the above-mentioned alkyl groups or alkylcarbonyl groups is 10 to 100% (100% substitution means one substituent per one monosaccharide unit); the degree of substitution of R2 with one of the above-mentioned carboxyalkyl groups is 50 to 200% (200% substitution means 2 substituents per one monosaccharide unit); and the molecular weight of the chitin is 500,000 or less] the molecular weight of the chitin in the formula (1) is desirably 100,000 or less.
An additional gist of this invention is a characteristic of the micelle-forming substances comprised of above-mentioned chitin derivatives, or polymer micellar carriers comprised of above-mentioned chitin derivatives. A further additional gist is micelle-like aqueous compositions with the above-mentioned chitin derivatives as polymer micellar carriers. The above-mentioned micelle-like aqueous compositions are the polymer micellar compositions include hydrophobic compounds. The hydrophobic compounds are exemplified by insoluble perfumes, insoluble pigments, or fats and oils.
The materials and the method for production are explained in the following.
As the starting chitin, which can have any crystalline structures, such as &agr;, &bgr;, or &ggr;-form, is available to produce a chitin derivative having hydrophilic groups and alkyl group as hydrophobic groups represented by the formula (1). Recrystallized or recomposed chitin, or chitosan (deacetylated chitin) is also available. Molecular weight and degree of deacetylation are not limited. Particle size is not limited, but smaller particle chitin is more easy to disperse in the solvent, the particle size can be chosen according to the purpose. When insufficiently pulverized chitin is used as source, excessive alkaline solution from the alkaline chitin preparation is removed by holding and pressing between filter papers after thawing frozen alkaline chitin, and then the amount corresponding to the weight loss of 55% aqueous sodium hydroxide solution is added to alkaline chitin to easy to swell the chitin.
The chitosan solution used in the present invention is prepared by using chitosan obtained by complete or partial deacetylation of chitin or chitosan contained abundantly in shells of crabs or shrimps and in squid pens.
In the p
Jinno Shuji
Kawahara Hiroyuki
Okita Yuji
Alexander Lyle A.
Armstrong Westerman Hattori McLeland & Naughton LLP
Cole Monique T.
Nippon Suisan Kaisha Ltd.
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