JPH0252930B2 - - Google Patents
Info
- Publication number
- JPH0252930B2 JPH0252930B2 JP20544682A JP20544682A JPH0252930B2 JP H0252930 B2 JPH0252930 B2 JP H0252930B2 JP 20544682 A JP20544682 A JP 20544682A JP 20544682 A JP20544682 A JP 20544682A JP H0252930 B2 JPH0252930 B2 JP H0252930B2
- Authority
- JP
- Japan
- Prior art keywords
- molecular weight
- polylactide
- lactic acid
- pressure
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 claims description 32
- 229920000747 poly(lactic acid) Polymers 0.000 claims description 24
- 235000014655 lactic acid Nutrition 0.000 claims description 16
- 239000004310 lactic acid Substances 0.000 claims description 16
- 238000006068 polycondensation reaction Methods 0.000 claims description 10
- 239000003054 catalyst Substances 0.000 claims description 9
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 238000010438 heat treatment Methods 0.000 claims description 3
- 239000011261 inert gas Substances 0.000 claims description 3
- JVTAAEKCZFNVCJ-REOHCLBHSA-N L-lactic acid Chemical compound C[C@H](O)C(O)=O JVTAAEKCZFNVCJ-REOHCLBHSA-N 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- ADCOVFLJGNWWNZ-UHFFFAOYSA-N antimony trioxide Chemical compound O=[Sb]O[Sb]=O ADCOVFLJGNWWNZ-UHFFFAOYSA-N 0.000 description 4
- 230000009477 glass transition Effects 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 238000009833 condensation Methods 0.000 description 3
- 230000005494 condensation Effects 0.000 description 3
- 238000006297 dehydration reaction Methods 0.000 description 3
- JJTUDXZGHPGLLC-UHFFFAOYSA-N lactide Chemical compound CC1OC(=O)C(C)OC1=O JJTUDXZGHPGLLC-UHFFFAOYSA-N 0.000 description 3
- 239000012567 medical material Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000035484 reaction time Effects 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- -1 and racemic D Chemical compound 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- WTEOIRVLGSZEPR-UHFFFAOYSA-N boron trifluoride Chemical compound FB(F)F WTEOIRVLGSZEPR-UHFFFAOYSA-N 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 230000007062 hydrolysis Effects 0.000 description 2
- 238000006460 hydrolysis reaction Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- ODNBVEIAQAZNNM-UHFFFAOYSA-N 1-(6-chloroimidazo[1,2-b]pyridazin-3-yl)ethanone Chemical compound C1=CC(Cl)=NN2C(C(=O)C)=CN=C21 ODNBVEIAQAZNNM-UHFFFAOYSA-N 0.000 description 1
- GUNJVIDCYZYFGV-UHFFFAOYSA-K Antimony trifluoride Inorganic materials F[Sb](F)F GUNJVIDCYZYFGV-UHFFFAOYSA-K 0.000 description 1
- 229910015900 BF3 Inorganic materials 0.000 description 1
- 229930182843 D-Lactic acid Natural products 0.000 description 1
- JVTAAEKCZFNVCJ-UWTATZPHSA-N D-lactic acid Chemical compound C[C@@H](O)C(O)=O JVTAAEKCZFNVCJ-UWTATZPHSA-N 0.000 description 1
- 241001465754 Metazoa Species 0.000 description 1
- 229910021627 Tin(IV) chloride Inorganic materials 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 230000036760 body temperature Effects 0.000 description 1
- 210000000988 bone and bone Anatomy 0.000 description 1
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 1
- 210000000845 cartilage Anatomy 0.000 description 1
- 238000006482 condensation reaction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 229940022769 d- lactic acid Drugs 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 150000005690 diesters Chemical class 0.000 description 1
- HQWPLXHWEZZGKY-UHFFFAOYSA-N diethylzinc Chemical compound CC[Zn]CC HQWPLXHWEZZGKY-UHFFFAOYSA-N 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 238000001727 in vivo Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- WWZKQHOCKIZLMA-UHFFFAOYSA-N octanoic acid Chemical compound CCCCCCCC(O)=O WWZKQHOCKIZLMA-UHFFFAOYSA-N 0.000 description 1
- 230000000399 orthopedic effect Effects 0.000 description 1
- 239000000575 pesticide Substances 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 238000007151 ring opening polymerisation reaction Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000013268 sustained release Methods 0.000 description 1
- 239000012730 sustained-release form Substances 0.000 description 1
- 229920001059 synthetic polymer Polymers 0.000 description 1
- HPGGPRDJHPYFRM-UHFFFAOYSA-J tin(iv) chloride Chemical compound Cl[Sn](Cl)(Cl)Cl HPGGPRDJHPYFRM-UHFFFAOYSA-J 0.000 description 1
- 210000001519 tissue Anatomy 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
Description
本発明は、医療用材料等として有用な高分子量
ポリラクタイドの製造方法に関する。
乳酸は自然界に広く分布し、動植物および人畜
に対して無害であり、その重合体（ポリラクタイ
ド）は水の存在下で比較的容易に加水分解を受
け、また生体内でも加水分解され吸収されるとこ
ろから医療用の合成高分子材料として注目されて
いる。
乳酸は分子内に水酸基とカルボキシル基を有す
るために重縮合が可能であるが、従来までに行な
われた脱水縮合では分子量が4000末満の低重合度
のオリゴマーしか得られないという欠点を有する
（Ｃ，Ｈ，Haten著、“Lactic Acid”Ｐ−226，
Verag Chemie，1971）。従つて、分子量が
4000以上の高分子量ポリラクタイドを得るには、
乳酸を単に脱水縮合させるのではなく、乳酸を脱
水縮合して乳酸のオリゴマーとし、これを三酸化
アンチモン、三弗化アンチモン、四塩化スズ等の
如き触媒の存在下で解重合して乳酸の環状ジエス
テル（ラクタイド）とし、これにオクチル酸ス
ズ、ジエチル亜鉛、三弗化ホウ素等の如き触媒を
加えて開環重合する方法が広く一般的に採用され
ている（例えば特公昭56−14688）。
しかし、この方法は、操作が繁雑である上に生
成物は悪鉛とかスズの如き毒性の懸念される金属
を含んでいることから、医療用材料として適当で
あるとはいい難い。従つて、ポリラクタイドを簡
便容易に、しかも人体に有害な不純物を含まない
状態で製造する方法が強く要望されている。
本発明者らは、高分子量のポリラクタイドを得
るべく、乳酸の重縮合反応について種々検討した
結果、反応条件を特定すれば、触媒を全く用いず
に乳酸を直接脱水縮合せしめるだけで、分子量が
4000以上のポリラクタイドが得られることを見出
し、本発明に至つた。
即ち、本発明は、乳酸を不活性ガス雰囲気中、
触媒の不存在下に加熱し、圧力を降下させて重縮
合させ、最終的に温度220〜260℃、圧力10mmHg
以下の条件で重縮合を完結させて分子量が少なく
とも4000のポリラクタイドを得ることを特徴とす
る高分子量ポリラクタイドの製造方法に関する。
本発明の製造方法によれば、ポリラクタイドは
触媒の不存在下で製造されるため、触媒に由来す
る不純物を全く含んでいない点で毒性の心配がな
く、医療用材料として生体内での使用に好適であ
るばかりでなく、製法が極めて単純で、かつ高分
子量のポリラクタイドが容易に得られるという点
でも甚だ好都合である。これは従来までに行なわ
れた脱水縮合では、高分子量のポリラクタイドを
得ることができないとする前記Ｃ，Ｈ，Haten
の知見からすと予期せぬことといわざるを得な
い。
次に、ポリラクタイドの製造方法について、本
発明方法と従来方法（特公昭56−14688号）とを
比較してみると下記のごとくである。
The present invention relates to a method for producing high molecular weight polylactide useful as a medical material and the like. Lactic acid is widely distributed in nature and is harmless to animals, plants, and humans. Its polymer (polylactide) is relatively easily hydrolyzed in the presence of water, and is also hydrolyzed and absorbed in living organisms. It is attracting attention as a synthetic polymer material for medical use. Lactic acid can be polycondensed because it has hydroxyl and carboxyl groups in its molecule, but it has the disadvantage that conventional dehydration condensation can only yield oligomers with a molecular weight of less than 4000 and a low degree of polymerization ( C. H. Haten, “Lactic Acid” P-226,
Verag Chemie, 1971). Therefore, the molecular weight
To obtain high molecular weight polylactide of 4000 or more,
Rather than simply dehydrating and condensing lactic acid, lactic acid is dehydrated and condensed to form lactic acid oligomers, which are then depolymerized in the presence of a catalyst such as antimony trioxide, antimony trifluoride, tin tetrachloride, etc. to form cyclic lactic acid. A method of ring-opening polymerization of a diester (lactide) by adding a catalyst such as tin octylate, diethylzinc, boron trifluoride, etc. is widely and generally adopted (for example, Japanese Patent Publication No. 14688/1988). However, this method is difficult to operate and the product contains metals that may be toxic, such as lead and tin, so it cannot be said to be suitable as a medical material. Therefore, there is a strong need for a method for producing polylactide simply and easily, and without containing impurities harmful to the human body. The present inventors have conducted various studies on the polycondensation reaction of lactic acid in order to obtain polylactide with a high molecular weight, and found that if the reaction conditions are specified, the molecular weight can be increased by directly dehydrating and condensing lactic acid without using any catalyst.
It was discovered that a polylactide of 4,000 or more can be obtained, leading to the present invention. That is, the present invention provides lactic acid in an inert gas atmosphere,
Polycondensation is carried out by heating in the absence of a catalyst and reducing the pressure, finally at a temperature of 220-260℃ and a pressure of 10mmHg.
The present invention relates to a method for producing a high molecular weight polylactide, which is characterized by completing polycondensation under the following conditions to obtain a polylactide having a molecular weight of at least 4000. According to the production method of the present invention, polylactide is produced in the absence of a catalyst, so there is no concern about toxicity as it does not contain any impurities derived from the catalyst, and it can be used in vivo as a medical material. It is not only suitable but also extremely advantageous in that the manufacturing method is extremely simple and high molecular weight polylactide can be easily obtained. This is because the C, H, Haten
I have to say that this was unexpected given my knowledge. Next, regarding the method for producing polylactide, a comparison between the method of the present invention and the conventional method (Japanese Patent Publication No. 14688/1988) is as follows.
【表】
本発明において使用される乳酸とは、Ｌ−乳
酸、Ｄ−乳酸、ラセミ体であるＤ，Ｌ−乳酸であ
る。
乳酸の重縮合反応は、乳酸を窒素やアルゴンの
ごとき不活性ガス雰囲気中、触媒の不存在に連続
的にあるいは段階的に加熱して昇温させると共
に、圧力を連続的あるいは段階的に降下させて縮
合水の留出のもとに重縮合させ、最終的に温度
220〜260℃、圧力10mmHg以下の条件下で重縮合
反応を完結させることにより行なわれる。
最終の縮合温度が220℃末満、または最終圧力
が10mmHgより高い場合には、生成するポリラク
タイドの分子量が4000未満にとどまる。一方、最
終の縮合温度が260℃を越えると、生成するポリ
ラクタイドは暗褐色となるばかりでなく、熱解重
合が優勢となつて、その分子量が4000未満とな
る。
本発明の製造方法によれば、分子量が4000以
上、特に分子量が4000〜20000の範囲のポリラク
タイドが容易に得られる。この範囲の分子量を有
するポリラクタイドのガラス転移温度は20〜45℃
であり、従つてそれらが体内で使用される場合、
体温で充分に柔軟となり、周囲の生体組織を損傷
することがなく、好ましいと考えられる。
一般にポリラクタイドの加水分解速度は分子量
に大きく依存し、分子量が高い程加水分解に要す
る時間が長くなる。従つて、徐放性薬剤としては
適当な時間で分解するという意味からも分子量の
余り高くない、4000〜20000程度の大きさの分子
量を有するポリラクタイドが有効な場合が多い。
遅効性農薬用にも同様ことが期待される。手術用
縫合糸とか整形外料用の骨補綴用材料等のように
高い機械的強度が要求される場合には当然高分子
量のポリラクタイドが必須であるが、軟骨のよう
な中程度の強度とか適度な分解速度が要求される
場合には本発明程度の分子量のポリラクタイドが
極めて有効と考えられる。
以下、実施例によつて本発明を更に詳しく説明
する。
実施例 １
冷却器、温度計、撹拌器および窒素ガス導入キ
ヤピラリーを備えた500mlの３つ口フラスコに、
市販のＤ，Ｌ−乳酸（85〜92重量％水溶液）500
ｇを仕込み、窒素ガスを吹き込みながら180℃で
４時間脱水反応させた後、真空ポンプにて徐々に
20mmHgまで減圧し、更に２時間脱水反応させた
（この状態で反応を終了させた場合、ゲルパーミ
エーシヨンクロマトグラフイーによつて分子量を
測定すると分子量は2000であつた。また、DSC
によつてガラス転移温度を測定すると22℃であつ
た。）。その後、更に温度を徐々に上げ、かつ圧力
を徐々に下げて最終的に260℃の温度、２mmHgの
圧力で８時間反応させた。260℃，２mmHgにして
からの反応時間と得られたポリラクタイドの分子
量、ガラス転移温度の関係は第１表のごとくであ
つた。[Table] Lactic acid used in the present invention is L-lactic acid, D-lactic acid, and racemic D,L-lactic acid. The polycondensation reaction of lactic acid is performed by heating lactic acid in an inert gas atmosphere such as nitrogen or argon in the absence of a catalyst to raise the temperature, and then lowering the pressure continuously or stepwise. Polycondensation is carried out by distillation of condensed water, and finally the temperature is
It is carried out by completing the polycondensation reaction under conditions of 220 to 260°C and a pressure of 10 mmHg or less. If the final condensation temperature is below 220°C or the final pressure is higher than 10 mmHg, the molecular weight of the polylactide produced remains below 4000. On the other hand, when the final condensation temperature exceeds 260°C, the polylactide produced not only becomes dark brown, but also undergoes thermal depolymerization and has a molecular weight of less than 4,000. According to the production method of the present invention, polylactide having a molecular weight of 4,000 or more, particularly a molecular weight in the range of 4,000 to 20,000, can be easily obtained. The glass transition temperature of polylactide with molecular weight in this range is 20-45℃
and therefore when they are used internally,
It is considered preferable because it becomes sufficiently flexible at body temperature and does not damage surrounding living tissue. Generally, the hydrolysis rate of polylactide largely depends on its molecular weight, and the higher the molecular weight, the longer the time required for hydrolysis. Therefore, polylactide having a molecular weight of about 4,000 to 20,000, which is not too high in molecular weight, is often effective as a sustained-release drug in the sense that it decomposes in a suitable time.
The same is expected for slow-acting pesticides. Naturally, high-molecular-weight polylactide is essential when high mechanical strength is required, such as surgical sutures or bone prosthetic materials for non-orthopedic materials, but polylactide with moderate strength, such as cartilage, is essential. When a high decomposition rate is required, a polylactide having a molecular weight similar to that of the present invention is considered to be extremely effective. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 In a 500 ml three-necked flask equipped with a condenser, thermometer, stirrer and nitrogen gas introduction capillary,
Commercially available D,L-lactic acid (85-92% by weight aqueous solution) 500
After dehydration reaction at 180℃ for 4 hours while blowing nitrogen gas, gradually dehydrate using a vacuum pump.
The pressure was reduced to 20 mmHg, and the dehydration reaction was further carried out for 2 hours.
The glass transition temperature was measured to be 22°C. ). Thereafter, the temperature was further gradually raised and the pressure was gradually lowered, and the reaction was finally carried out at a temperature of 260° C. and a pressure of 2 mmHg for 8 hours. Table 1 shows the relationship between the reaction time at 260°C and 2 mmHg, the molecular weight of the polylactide obtained, and the glass transition temperature.
【表】
実施例 ２
出発原料として市販のＬ−乳酸（90％水溶液）
を用いた以外は実施例１と同様の条件で重縮合反
応させ、分子量18000、ガラス転移温度42℃の淡
黄色のポリラクタイドを得た。
比較例 １
実施例１の重縮合条件において、最終圧力をそ
のまま一定の２mmHgにして最終温度のみを280℃
に高めたところ、折角、分子量を高めたにもかか
わらず、重合体の熱解重合が優勢となり、乳酸の
環状ジエステルであるラクタイドが著しく生成し
てきた。また、生成物は暗褐色を呈し、その分子
量も4000未満であつた。
比較例 ２
実施例１の重縮合条件において、最終温度のみ
を一定の260℃にし、最終圧力を20mmHgにして反
応を進めたところ、反応時間を長くしても分子量
は4000以上にはならない上に反応時間が８〜10時
間と長くなると生成物が暗褐色に変化してきた。
比較例 ３
実施例１の反応温度（180℃）と圧力（20mm
Hg）は、そのままにして、そこへさらに三酸化
アンチモン触媒を乳酸モノマーに対して１重量パ
ーセント添加して縮合反応を行なうと、圧力20mm
Hg、反応温度180℃という比較的低温においても
ラクタイドが激しく生成してきた。[Table] Example 2 Commercially available L-lactic acid (90% aqueous solution) as starting material
A polycondensation reaction was carried out under the same conditions as in Example 1 except that a pale yellow polylactide having a molecular weight of 18,000 and a glass transition temperature of 42°C was obtained. Comparative Example 1 Under the polycondensation conditions of Example 1, the final pressure was kept constant at 2 mmHg, and only the final temperature was changed to 280°C.
When the molecular weight was increased, thermal depolymerization of the polymer became predominant, and lactide, a cyclic diester of lactic acid, was produced significantly. Furthermore, the product exhibited a dark brown color and its molecular weight was less than 4,000. Comparative Example 2 Under the polycondensation conditions of Example 1, only the final temperature was kept constant at 260°C and the final pressure was set at 20 mmHg to proceed with the reaction. Even if the reaction time was increased, the molecular weight did not increase to 4000 or more. As the reaction time increased to 8-10 hours, the product turned dark brown. Comparative Example 3 Reaction temperature (180℃) and pressure (20mm
Hg) is left as it is, and an antimony trioxide catalyst is further added thereto in an amount of 1% by weight based on the lactic acid monomer to perform a condensation reaction, resulting in a pressure of 20 mm.
Lactide was produced vigorously even at relatively low Hg and reaction temperatures of 180°C.
Claims (1)
に加熱し、圧力を降下させて重縮合させ、最終的
に温度220〜260℃、圧力10mmHg以下の条件下で
重縮合反応を完結させて分子量が少なくとも4000
のポリラクタイドを得ることを特徴とする高分子
量ポリラクタイドの製造方法。1. Heating lactic acid in an inert gas atmosphere in the absence of a catalyst, lowering the pressure and polycondensing it, and finally completing the polycondensation reaction at a temperature of 220 to 260°C and a pressure of 10 mmHg or less. molecular weight of at least 4000
A method for producing a high molecular weight polylactide, which is characterized by obtaining a polylactide of.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20544682A JPS5996123A (en) | 1982-11-25 | 1982-11-25 | Production of high-molecular weight polylactide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20544682A JPS5996123A (en) | 1982-11-25 | 1982-11-25 | Production of high-molecular weight polylactide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5996123A JPS5996123A (en) | 1984-06-02 |
| JPH0252930B2 true JPH0252930B2 (en) | 1990-11-15 |
Family
ID=16507009
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20544682A Granted JPS5996123A (en) | 1982-11-25 | 1982-11-25 | Production of high-molecular weight polylactide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5996123A (en) |
Families Citing this family (43)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0678425B2 (en) * | 1984-07-06 | 1994-10-05 | 和光純薬工業株式会社 | New polymer manufacturing method |
| JP2714454B2 (en) * | 1988-11-07 | 1998-02-16 | 三井東圧化学株式会社 | Method for producing bioabsorbable polyester |
| EP0572675B1 (en) * | 1991-12-19 | 1999-09-22 | Mitsui Chemicals, Inc. | Polyhydroxy carboxylic acid and production thereof |
| US6096431A (en) | 1994-07-25 | 2000-08-01 | Toppan Printing Co., Ltd. | Biodegradable cards |
| US5646238A (en) * | 1994-07-27 | 1997-07-08 | Mitsui Toatsu Chemicals, Inc. | Preparation process of polyhydroxycarboxylic acid |
| JP2968466B2 (en) * | 1995-10-31 | 1999-10-25 | 株式会社日本触媒 | Method for producing aliphatic polyester |
| WO1999019378A1 (en) * | 1997-10-13 | 1999-04-22 | Kureha Kagaku Kogyo K.K. | Processes for producing polyhydroxy carboxylic acid and glycolide |
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-
1982
- 1982-11-25 JP JP20544682A patent/JPS5996123A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5996123A (en) | 1984-06-02 |
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