JPH0629281B2 - Method for producing low molecular weight chitosan - Google Patents
Method for producing low molecular weight chitosanInfo
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- JPH0629281B2 JPH0629281B2 JP817688A JP817688A JPH0629281B2 JP H0629281 B2 JPH0629281 B2 JP H0629281B2 JP 817688 A JP817688 A JP 817688A JP 817688 A JP817688 A JP 817688A JP H0629281 B2 JPH0629281 B2 JP H0629281B2
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- chitosan
- molecular weight
- low molecular
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Description
【発明の詳細な説明】 〔産業上の利用分野〕 この発明は低分子キトサンの製造方法、特に過酸化水素
によりキトサンを低分子化する方法に関するものであ
る。TECHNICAL FIELD The present invention relates to a method for producing low molecular weight chitosan, and more particularly to a method for reducing the molecular weight of chitosan with hydrogen peroxide.
キトサンはカチオン性高分子物質として凝集剤等に使用
されている。この場合、用途に応じて任意の分子量のキ
トサンが要求されるため、天然から得られるキトサンを
低分子化して低分子キトサンを製造している。従来、キ
トサンを低分子化する方法として、次の方法が知られて
いる。Chitosan is used as a flocculant as a cationic polymer substance. In this case, since a chitosan having an arbitrary molecular weight is required depending on the application, a low molecular weight chitosan is produced by lowering the molecular weight of naturally occurring chitosan. Conventionally, the following methods have been known as methods for reducing the molecular weight of chitosan.
pH６〜12で過酸化水素を0.007〜0.35重量％の濃度と
なるように添加する方法（特公昭56−33401号）。A method of adding hydrogen peroxide at a pH of 6 to 12 to a concentration of 0.007 to 0.35% by weight (Japanese Patent Publication No. 56-33401).
アルカリ処理による脱アセチル化と並行して、グリコ
シド結合の切断をはかる方法。A method of breaking the glycosidic bond in parallel with deacetylation by alkali treatment.
キチンを希酸で処理してグリコシド結合を切断後、脱
アセチル化する方法。A method in which chitin is treated with dilute acid to cleave the glycosidic bond and then deacetylated.
しかしながら、このような従来の方法には次のような問
題点があった。まずの方法では過酸化水素の添加量を
多くしても、無着色の低分化キトサンとしては分子量が
16,000位のものまでしか得られず、微黄色ないしは黄色
のものとしても12,000のキトサンまでしか得られない。
また，の方法でも、任意の分子量のキトサンを得る
ことが極めて困難であって、得られるキトサンの１重量
％酢酸溶液で粘度50cP以下のキトサンを得ることは困難
である。However, such a conventional method has the following problems. In the first method, even if the amount of hydrogen peroxide added was increased, the molecular weight of uncolored poorly differentiated chitosan was
You can only get up to about 16,000, and you can get up to 12,000 chitosan even if it is slightly yellow or yellow.
Also, it is extremely difficult to obtain chitosan having an arbitrary molecular weight by the method (1), and it is difficult to obtain chitosan having a viscosity of 50 cP or less with a 1% by weight acetic acid solution of chitosan obtained.
本発明の目的は、上記問題点を解決するため、従来のも
のよりもさらに分子量が低い低分子量キトサンを製造す
ることが可能な方法を提案することである。An object of the present invention is to propose a method capable of producing a low molecular weight chitosan having a lower molecular weight than conventional ones in order to solve the above problems.
本発明は、キトサンを酸に溶解し、次いでアルカリを添
加してキトサンを懸濁させた後、過酸化水素を添加する
ことを特徴とする低分子キトサンの製造方法である。The present invention is a method for producing a low molecular weight chitosan, which comprises dissolving chitosan in an acid, adding an alkali to suspend the chitosan, and then adding hydrogen peroxide.
本発明において製造する低分子キトサンの分子量の範囲
は、固有粘度〔η〕で表わすと、約0.20〜2.0dl/gのも
のである。この固有粘度のキトサンは、そのまま蒸留水
に懸濁させても溶解する程には低い分子量ではなく、ま
た前記特公昭56-33401号の方法で得られるものほど分子
量は高くない。また、アミノ基の含有率をコロイド当量
値（pH４で測定）で表わすと、4.0meq/gキトサン以上、
通常5.0meq/gキトサン以上であり、極めて高いアミノ基
含有率の低分子キトサンである。The low molecular weight chitosan produced in the present invention has a molecular weight range of about 0.20 to 2.0 dl / g, when expressed by an intrinsic viscosity [η]. Chitosan having this intrinsic viscosity does not have such a low molecular weight that it can be dissolved in distilled water as it is, and has a molecular weight not so high as that obtained by the method of Japanese Patent Publication No. 56-33401. When the content of amino groups is expressed as a colloid equivalent value (measured at pH 4), 4.0 meq / g chitosan or more,
It is usually 5.0 meq / g or more chitosan, and is a low molecular weight chitosan with an extremely high amino group content.
本発明において、キトサンの固有粘度〔η〕は、キトサ
ンをこれと同量の酢酸を用いて水に溶解し、この溶液と
同量の0.4N酢酸＋0.2N酢酸ナトリウムとを混合して測定
に用いる溶液を調製し、希釈には0.2N酢酸＋0.1N酢酸ナ
トリウムを用いて、30℃でウベローデ粘度計を用いて測
定した値である。In the present invention, the intrinsic viscosity [η] of chitosan is measured by dissolving chitosan in water using the same amount of acetic acid and mixing this solution with the same amount of 0.4N acetic acid + 0.2N sodium acetate. It is a value measured by using a Ubbelohde viscometer at 30 ° C. by preparing a solution to be used, using 0.2N acetic acid + 0.1N sodium acetate for dilution.
原料キトサンは、カニ、エビ等の節足動物の甲羅、殻等
を脱タンパク質、脱カルシウムして得られるキチンを全
部または一部脱アセチル化したもので、任意の純度、分
子量のものが使用できるが、できるだけ低分子量のもの
がよく、このため高分子量のキトサンは予め固有粘度
〔η〕が５dl/g以下となるように低分子化しておくのが
好ましい。The raw material chitosan is deacetylated chitin obtained by deproteinizing and decalcifying the shells and shells of arthropods such as crabs and shrimps, and can be used in any purity and molecular weight. However, it is preferable that the molecular weight is as low as possible. Therefore, it is preferable that the high molecular weight chitosan is previously made into a low molecular weight so that the intrinsic viscosity [η] is 5 dl / g or less.
カニ、エビ等の甲羅を脱タンパク質、脱カルシウムする
ことによってキチンが得られ、このキチンを脱アセチル
化するとキトサンが得られるが、このようにして得られ
るキトサンの分子量、脱アセチル化度は原料および処理
方法によってまちまちである。また、粉末は大きくて粉
砕しにくいため、粗粒子状、微粉末状、繊維状であり、
低分子化を行う場合、その分子量およびアミノ基の含有
率を制御することが困難である。そこで、キトサンを一
度酸を用いて溶液とし、次いでこれにアルカリを添加す
ることによって懸濁させると、微細で均一な粒径のキト
サンが得られるため、これに過酸化水素を添加して低分
子化を行うと、反応が十分行われ、分子量およびアミノ
基の含有率の制御が容易になる。Chitin is obtained by deproteinizing and decalcifying the shells of crabs, shrimps, etc. Chitosan is obtained by deacetylating this chitin. The molecular weight and degree of deacetylation of chitosan thus obtained are It depends on the processing method. In addition, since the powder is large and difficult to pulverize, it is in the form of coarse particles, fine powder, or fibre,
When lowering the molecular weight, it is difficult to control the molecular weight and the content ratio of amino groups. Therefore, once chitosan is made into a solution using an acid and then suspended by adding an alkali to this, chitosan with a fine and uniform particle size is obtained. When the reaction is carried out, the reaction is sufficiently carried out, and it becomes easy to control the molecular weight and the content ratio of amino groups.
この場合、カニ、エビ等の甲羅から得られたキトサンは
分子量が高いため、0.5〜１重量％程度の濃度にしかす
ることができず、このため溶解に１〜３時間程度の時間
を要するとともに、撹伴エネルギーも多大となり、さら
にキトサンを低分子化するのに大きな反応容器を必要と
する。そこでキトサンを予め固有粘度〔η〕が５dl/g以
下となるように低分子化することにより、２〜10重量％
程度の濃度に５〜10分間程度の時間で溶解することがで
き、しかるのちアルカリで懸濁させ、過酸化水素を添加
して低分子化すると、効率よく低分子キトサンを得るこ
とができるので好ましい。In this case, chitosan obtained from the shell of crab, shrimp, etc. has a high molecular weight, so that it can be made only at a concentration of about 0.5 to 1% by weight, and therefore it takes about 1 to 3 hours to dissolve it. However, the entrainment energy becomes large, and a large reaction vessel is required to further reduce the molecular weight of chitosan. Therefore, 2 to 10% by weight of chitosan was prepared by lowering the molecular weight of chitosan in advance so that the intrinsic viscosity [η] becomes 5 dl / g or less.
It is possible to dissolve at a certain concentration for about 5 to 10 minutes, and then suspend in an alkali and add hydrogen peroxide to lower the molecular weight, so that low molecular weight chitosan can be efficiently obtained, which is preferable. .
キトサンを予め低分子化する方法としては、前記した公
知方法を採用することができる。特に効率面から過酸化
水素を用いて予備処理する方法が好ましい。なお、予備
処理としての低分子化は固有粘度が５dl/g以下、好まし
くは１〜３dl/g程度とする。As a method of reducing the molecular weight of chitosan in advance, the above-mentioned known method can be adopted. From the viewpoint of efficiency, the method of pretreatment with hydrogen peroxide is particularly preferable. In addition, the lowering of the molecular weight as the pretreatment has an intrinsic viscosity of 5 dl / g or less, preferably about 1 to 3 dl / g.
キトサンを溶解するのに用いる酸としては酢酸、塩酸な
ど、キトサンを溶解できる酸であれば任意のものが使用
でき、水溶液として使用されるが、過酸化水素により分
解されないものが好ましい。キトサンを溶解する酸溶液
の酸の濃度は0.05〜20重量％、好ましくは0.5〜10重量
％、これに溶解するキトサンの濃度は0.05〜20重量％、
好ましくは0.5〜10重量％程度である。As the acid used to dissolve chitosan, any acid can be used as long as it can dissolve chitosan, such as acetic acid and hydrochloric acid, and it is used as an aqueous solution, but an acid that is not decomposed by hydrogen peroxide is preferable. The acid concentration of the acid solution that dissolves chitosan is 0.05 to 20% by weight, preferably 0.5 to 10% by weight, and the concentration of chitosan that is dissolved in it is 0.05 to 20% by weight,
It is preferably about 0.5 to 10% by weight.
キトサンを溶解した酸溶液は、アルカリ添加に先立って
濾過等により不溶解分を除去するのが好ましい。不溶解
分除去の方法は特に制限はないが、溶液の粘度が高いた
め、ステンレス鋼製金網等により濾過を行う方法が適し
ている。The acid solution in which chitosan is dissolved is preferably filtered to remove insoluble matter prior to addition of alkali. The method of removing the insoluble matter is not particularly limited, but a method of performing filtration with a stainless steel wire mesh or the like is suitable because the viscosity of the solution is high.
不溶解分を除去したキトサンの酸溶液は、アルカリを添
加してキトサンを懸濁させ、懸濁液とする。キトサンを
懸濁させるのに用いるアルカリも特に限定されず、水酸
化ナトリウム、水酸化カリウム等が使用できる。The acid solution of chitosan from which the insoluble matter has been removed is added with an alkali to suspend the chitosan to form a suspension. The alkali used for suspending chitosan is not particularly limited, and sodium hydroxide, potassium hydroxide and the like can be used.
こうして生成するキトサン懸濁液に過酸化水素を添加し
てキトサンの低分子化を行う。低分子化する時の条件は
特に限定されないが、白色粉末の低分子キトサンを得る
にはpH７〜12、温度40〜90℃の範囲が望ましい。Hydrogen peroxide is added to the chitosan suspension thus produced to lower the molecular weight of chitosan. The conditions for lowering the molecular weight are not particularly limited, but a pH range of 7 to 12 and a temperature range of 40 to 90 ° C. are desirable to obtain white powder of low molecular weight chitosan.
過酸化水素の添加量はキトサン１ｇに対して0.05〜1g、
好ましくは0.1〜0.3g程度であり、これを一度に添加す
ると、発泡やキトサンの変質等の問題があるため、連続
的または間欠的に分割して添加するのが望ましい。この
ときの過酸化水素の添加速度は0.01〜1g/・分、好ま
しくは0.05〜0.5g/・分とし、少なくとも４g/添加
するのが望ましい。低分子化の反応は攪拌しながら0.5
〜５時間、好ましくは１〜３時間行うことにより低分子
キトサンが得られる。The amount of hydrogen peroxide added is 0.05 to 1 g per 1 g of chitosan,
The amount is preferably about 0.1 to 0.3 g, and if this is added all at once, problems such as foaming and alteration of chitosan will occur, so it is desirable to add continuously or intermittently. The addition rate of hydrogen peroxide at this time is 0.01 to 1 g / min, preferably 0.05 to 0.5 g / min, and it is desirable to add at least 4 g / min. The reaction for lowering the molecular weight is 0.5 with stirring.
The low molecular weight chitosan can be obtained by performing the treatment for -5 hours, preferably 1-3 hours.
こうして得られる低分子キトサンは、固有粘度〔η〕が
約0.20〜2.0dl/gの極めて分子量の低いものであり、カ
ニ、エビ等の甲羅から得られたキトサンにそのまま多量
の過酸化水素を添加しても得られないものである。そし
て過酸化水素の添加量が多少多くなっても、白色〜淡黄
色で良質の低分子量キトサンが得られる。The low molecular weight chitosan thus obtained has an extremely low intrinsic molecular weight [η] of approximately 0.20 to 2.0 dl / g, and a large amount of hydrogen peroxide was added to chitosan obtained from the shells of crabs, shrimps, etc. Even if you don't get it. Even if the amount of hydrogen peroxide added increases a little, white to pale yellow and good quality low molecular weight chitosan can be obtained.
本発明によれば、キトサンを酸に溶解し、次いでアルカ
リを添加してキトサンを懸濁させた後、過酸化水素を添
加して低分子化するようにしたので、原料キトサンをそ
のまま過酸化水素で低分子化する場合に比べ、はるかに
低分子量であって、白色で良質の低分子キトサンを効率
よく製造することができる。According to the present invention, chitosan is dissolved in an acid, and then alkali is added to suspend the chitosan, and then hydrogen peroxide is added to lower the molecular weight of the chitosan. It is possible to efficiently produce white and high-quality low-molecular-weight chitosan, which has a much lower molecular weight than the case where the low-molecular-weight chitosan is used.
また、予め固有粘度が５dl/g以下にまで予備的に低分子
化したキトサンを用いると、酸溶解時間が短時間です
み、溶解濃度も増加するうえ、撹拌エネルギーも少なく
てすむ。Further, when chitosan whose intrinsic viscosity is preliminarily lowered to 5 dl / g or less is used, the acid dissolution time is short, the dissolution concentration is increased, and the stirring energy is also small.
以下、本発明の実施例について説明する。なお、％は重
量％である。Examples of the present invention will be described below. In addition,% is weight%.
実施例１〜３、比較例１〜３ 原料キトサンの粒子径の分布を篩を用いて測定した。９
メッシュ通過〜200メッシュ残留の範囲にあり、平均粒
子径は16〜24メッシュの間にあった。このキトサンの物
性値を次に示す。Examples 1 to 3 and Comparative Examples 1 to 3 The particle size distribution of the raw material chitosan was measured using a sieve. 9
The average particle size was in the range of 16 to 24 mesh, with the range of passing through mesh to remaining of 200 mesh. The physical properties of this chitosan are shown below.
蒸発残分*1／製品＝90.4％ 灰分*2／蒸発残分＝2.1％ 固有粘度*3＝13.8（dl/gキトサン*4） コロイド当量値(CE,pH4)＝5.1meq/gキトサン*4 *1 105℃ *2 600℃ *3 30℃、0.2N酢酸＋0.1N酢酸ナトリウム *4 キトサン＝蒸発残分−灰分とした。Evaporation residue * 1 / Product = 90.4% Ash content * 2 / Evaporation residue = 2.1% Intrinsic viscosity * 3 = 13.8 (dl / g chitosan * 4) Colloid equivalent value (CE, pH4) = 5.1 meq / g chitosan * 4 * 1 105 ℃ * 2 600 ℃ * 3 30 ℃, 0.2N acetic acid + 0.1N sodium acetate * 4 Chitosan = evaporation residue-ash content.
原料キトサン50gを、純水5.0と濃塩酸50mlを用いて溶
解し（10時間）、これを攪拌機を用いて十分に攪拌しな
がら、NaOH溶液を用いてpH11に調整してキトサンを懸濁
させ、全量を6.0にした。50 g of raw material chitosan was dissolved with 5.0 of pure water and 50 ml of concentrated hydrochloric acid (10 hours), and while sufficiently stirring it with a stirrer, pH was adjusted to 11 with NaOH solution to suspend chitosan, The total amount was 6.0.
これを、次の条件でH2O2水を添加し、攪拌機を用いて十
分に攪拌しながらキトサンの低分子化を行った。Under this condition, H 2 O 2 water was added under the following conditions, and the molecular weight of chitosan was reduced with sufficient stirring using a stirrer.
反応温度 70℃ pH 11.0 反応時間 ２時間 H2O2 0.7〜7.0g/l（35％H2O2水溶液を添加）添加方
法は、1.5ml/6・分（＝0.088gH2O2/・分）の速度で
ローラーポンプを用いて添加した。METHOD reaction temperature 70 ° C. pH 11.0 reaction time 2 hours H 2 O 2 0.7~7.0g / l (added 35% H 2 O 2 solution) addition, 1.5 ml / 6 · min (= 0.088gH 2 O 2 / · Min) with a roller pump.
比較例として、濃塩酸を添加することによるキトサンの
溶解およびNaOH溶液を添加することによるキトサンの沈
殿という操作を行わずに、同じ条件で低分子化反応を行
った。As a comparative example, the molecular weight reduction reaction was performed under the same conditions without performing the operations of dissolving chitosan by adding concentrated hydrochloric acid and precipitating chitosan by adding a NaOH solution.
低分子化反応終了後のキトサンは、室温に冷却後NaBH4
を添加して還元処理した後、ポリプロピレン製濾布を用
いて濾過した。次いで純水を用いて洗浄濾過する操作を
繰り返し、溶解している極低分子量キトサン、塩類、過
剰のNaOHを除去した後、凍結乾燥して低分子量キトサン
試料を得た。After the molecular weight reduction reaction is completed, chitosan is cooled to room temperature and then NaBH 4
Was added to carry out a reduction treatment and then filtered using a polypropylene filter cloth. Then, the operation of washing and filtering with pure water was repeated to remove the dissolved extremely low molecular weight chitosan, salts and excess NaOH, and then freeze-dried to obtain a low molecular weight chitosan sample.
得られた試料について、物性と色調を調べた結果を表１
に示す。The results of examining the physical properties and color tone of the obtained sample are shown in Table 1.
Shown in.
以上の結果実施例１〜３では、〔η〕が大きく低下し、
CEの低下は比較例ほど激しくない。また、得られた粉末
は白色〜淡黄色である。これに対して比較例１〜３で
は、H2O2を添加しても〔η〕があまり低下せず、CEが低
下する。また得られた粉末は黄褐色〜茶褐色である。 As a result of the above, in Examples 1 to 3, [η] significantly decreased,
The decrease in CE is not as severe as in the comparative example. Moreover, the obtained powder is white to pale yellow. On the other hand, in Comparative Examples 1 to 3, even if H 2 O 2 is added, [η] does not decrease so much and CE decreases. The obtained powder is yellowish brown to dark brown.
以上の結果から、キトサンを酸、アルカリ処理すること
により、従来例では得られなかったような低分子キトサ
ンが得られることがわかる。From the above results, it can be seen that by treating chitosan with an acid or an alkali, a low molecular weight chitosan which could not be obtained in the conventional example can be obtained.
実施例４ 実施例１の原料キトサン400gを純水６に懸濁し、70
℃、pH11に調整後30gのH2O2水を加え、撹拌しながらさ
らに1.5ml／6・分の速度でH2O2水を供給した。全部で
56ｇのH2O2の供給が終了してから、30分間そのままの状
態（70℃、pH11、撹拌）に保った。Example 4 400 g of the raw material chitosan of Example 1 was suspended in pure water 6 to prepare 70
After adjusting the temperature to pH 11 and 30 g, 30 g of H 2 O 2 water was added, and H 2 O 2 water was further supplied at a rate of 1.5 ml / 6 · min while stirring. In all
After the supply of 56 g of H 2 O 2 was completed, it was kept as it was (70 ° C., pH 11, stirring) for 30 minutes.
30分後に金網上に反応懸濁液を移し、十分に洗浄後、減
圧乾燥してキトサン粉末を得た。このものの固有粘度は
５dl/g、コロイド当量は5.0meq/gであった。After 30 minutes, the reaction suspension was transferred onto a wire net, thoroughly washed, and dried under reduced pressure to obtain a chitosan powder. This had an intrinsic viscosity of 5 dl / g and a colloid equivalent of 5.0 meq / g.
次にこの予備低分子化キトサン310gに310mlの濃塩酸と
純水５を添加して溶解した。溶解時間は10分間で、濃
度は5.8％であった。Next, 310 ml of concentrated hydrochloric acid and pure water 5 were added to and dissolved in 310 g of this preliminary low molecular weight chitosan. The dissolution time was 10 minutes and the concentration was 5.8%.
溶解液を濾過して不溶解分を除去後、撹拌しながら水酸
化ナトリウムでpH11に調整してキトサンを懸濁させ、全
量を６とし、これを実施例１と同様にしてH2O2水を49
ｇ添加したものについて粉末化したところ、固有粘度が
0.27dl/g、コロイド当量が4.8meq/g、収率24％であるこ
とがわかった。After the solution was filtered to remove insoluble matter, the pH was adjusted to 11 with sodium hydroxide while stirring to suspend the chitosan, and the total amount was set to 6, which was treated with H 2 O 2 water in the same manner as in Example 1. A 49
When powdered with added g, the intrinsic viscosity was
It was found to be 0.27 dl / g, the colloid equivalent was 4.8 meq / g, and the yield was 24%.
Claims (2)
添加してキトサンを懸濁させた後、過酸化水素を添加す
ることを特徴とする低分子キトサンの製造方法。1. A method for producing a low molecular weight chitosan, which comprises dissolving chitosan in an acid, adding an alkali to suspend the chitosan, and then adding hydrogen peroxide.
うに、予め低分子化されたものである請求項１記載の低
分子キトサンの製造方法。2. The method for producing low molecular weight chitosan according to claim 1, wherein the molecular weight of chitosan is previously reduced to an intrinsic viscosity of 5 dl / g or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP817688A JPH0629281B2 (en) | 1988-01-18 | 1988-01-18 | Method for producing low molecular weight chitosan |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP817688A JPH0629281B2 (en) | 1988-01-18 | 1988-01-18 | Method for producing low molecular weight chitosan |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01185301A JPH01185301A (en) | 1989-07-24 |
| JPH0629281B2 true JPH0629281B2 (en) | 1994-04-20 |
Family
ID=11686008
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP817688A Expired - Fee Related JPH0629281B2 (en) | 1988-01-18 | 1988-01-18 | Method for producing low molecular weight chitosan |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0629281B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH089641B2 (en) * | 1988-05-13 | 1996-01-31 | 大日精化工業株式会社 | Method for producing low molecular weight chitosan |
| AU2003201052A1 (en) * | 2002-01-09 | 2003-07-24 | Abbott Laboratories De Costa Rica Ltd | Methods of producing modified microcrystalline chitosan and uses therefor |
| JP2010208995A (en) * | 2009-03-10 | 2010-09-24 | Japan Atomic Energy Agency | Method for producing plant-vitalizing agent, and method for growing plant using the plant-vitalizing agent |
| CN102702386A (en) * | 2012-06-14 | 2012-10-03 | 中国科学院海洋研究所 | Method for degrading chitosan |
| CN103030714B (en) * | 2012-12-21 | 2014-09-24 | 江南大学 | Preparation method of low-molecular-weight chitosan oligosaccharide sulfamide derivate with hypoglycemic activity |
-
1988
- 1988-01-18 JP JP817688A patent/JPH0629281B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01185301A (en) | 1989-07-24 |
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