HK1189013B - Method for preparing star polymers - Google Patents
Method for preparing star polymers Download PDFInfo
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- HK1189013B HK1189013B HK14102082.9A HK14102082A HK1189013B HK 1189013 B HK1189013 B HK 1189013B HK 14102082 A HK14102082 A HK 14102082A HK 1189013 B HK1189013 B HK 1189013B
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- tribitol
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Description
The present application concerns a process for the preparation of star polymers based on lactide and/or glycolide. This process is easily controllable and has a higher efficiency than the previous state-of-the-art.
In this respect, lactic and glycolic acid copolymers (GLPAs) are of great interest because they are sensitive to hydrolysis and are degraded in proportion to release of non-toxic by-products. The application of these principles is very extensive (Adv. Mat. 1996, Chromosphere 30, 43, and 49). In the field of pharmaceutical chemistry, they are used for the control of cell structure, cell release, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell cycle, cell
The branched polymers, including star polymers, dendrimers and hyperbranched polymers, have been the subject of extensive research because of their interesting rheological and mechanical properties.
In particular, star polymers, or star-architecture polymers, can be used in the administration of active ingredients and have interesting release profiles.
In addition, star polymers have different glass transition temperatures, as well as a different viscosity in the glass state, from their linear equivalents. The same is true of their crystallinity - and therefore their melting temperature - which is also different from their linear equivalents. In particular, high molecular mass polymers are described as having a lower glass transition temperature and melting temperature than their linear equivalents.
A biodegradable star polymer (e.g. PLGA) will have a much faster initial degradation rate than its linear equivalent of the same mass. Indeed, it has been shown that by chemical or enzymatic hydrolysis, the first ester bond cuts take place in the star core, close to the starter, thus releasing linear polymers of lower molecular masses. Thus, the rate of expansion and degradation is to be correlated with the structure of the polymer matrix.
For example, the encapsulation of active ingredients in star polymers for PLGAs was described by A. Breitenbach, Y. X. Li, T. Kissel, Journal of Controlled Release 2000, 64, 167.
Cycle-opening polymerization from metal complexes for the synthesis of star polymers has been described as early as the 1990s. They are mainly prepared in solution or in bulk, with metal catalysts such as tin octanoate, although other systems based on Fe, Zn, Al... have been reported (H.R. Kricheldorf, Polymer for Advanced Technologies 2002, 13, 969 ; A. Finne, A.-C. Albertsson, Biomacromolecules 2002, 3, 684 ; H. R. Kricheldorf, H. Hachmann-Thiessen, G. Schwarz, Biomacromolecules 2004, 5, 492 I. Arvanayannis, A. Nakamoto, E. Kaadou, N. Kawasaki, N. Yamamoto, 1996, Ps. 367, 651).
There are very few examples in the literature of synthesis of lactic acid-based polymers (PLA) stars with non-metallic catalysts. In 2007, K. Numata, R. K. Srivastava, A. Finne-Wistrand, A.-C. Albertsson, Y. Doi, H. Abe, Biomacromolecules 2007, 8, 3115 first described the enzymatic mass polymerization of the lactide in the presence of polyols. PLA stars, 2 to 22 branches, are obtained, with polymorphism indices ranging from 1.0 to 1.5 in the presence of lipase, at 140°C, after 5 to 7 days of polymerization.
Examples of preparation of star-shaped polyesters by means of organic catalysts are monomers other than lactide, such as δ-valerolactone or e-caprolactone (F. Sanda, H. Sanada, Y. Shibasaki, T. Endo, Macromolecules 2002, 35, 680; P. V. Persson, J. Casas, T. Iversen, A. Cordova, Macromolecules 2006, 39, 2819 and F. Zeng, H. Lee, M. Chidiac, C. Allen, Biomacromolecules 2005, 6, 2140).
The examples described in the introduction to the organocatalyzed lactide cycle are all based on macroamorphosants.
The applicant has developed a new non-metallic process which is easily controllable and has a higher efficiency than the previous state-of-the-art process for oligomers.
The object of the invention is therefore a process for preparing star polymers from a lactide monomer and a glycolide monomer or a lactide monomer by opening a cycle in the presence of a catalyst, in which the catalyst has the formula:
- What?
where R is a haloalkyl in C1 through C6; the starter is a polyol with 3 to 6 hydroxyl functions.
Preferably, the monomer is the lactide.
Preferably, the polymers are prepared from a lactide monomer and a glycolide monomer.
Preferably, the reaction takes place in an organic solvent, and even more preferably in a halogenated or aromatic solvent.
The solvent is preferably a halogenated solvent, preferably the solvent is dichloromethane.
Preferably, the starter is a polyol with 3 to 4 hydroxyl functions.
Preferably, the trigger is glycerol.
The catalyst is preferably trifluoromethanesulfonic acid.
The reaction temperature is preferably 0 to 150°C, preferably 20 to 45°C.
Preferably, the initial monomer concentration/OH concentration ratio of the starter is 200/1 to 1/1.
Preferably the initial monomer concentration/OH function concentration ratio of the starter is 100/1 to 2/1.
Preferably the initial monomer concentration/OH function concentration ratio of the starter is 20/1 to 4/1.
Preferably, the initial catalyst concentration/OH concentration ratio of the starter is 0.1 to 20.
Preferably, the initial catalyst concentration/OH concentration ratio of the starter is 0.2 to 10.
Preferably, the initial catalyst concentration/OH concentration ratio of the starter is 0.3 to 6.
The purpose of the invention is therefore to prepare star polymers based on a lactide and/or glycolide.
The polymerization reaction is of the cycle-opening type.
- What?
n with the number of monomers.
The reaction is performed from a lactide monomer and a glycolide monomer, or from a lactide monomer alone. One variant states that the monomer is the lactide. Another variant states that the reaction is a copolymerization and the reaction is performed from the lactide and glycolide.
The reaction is carried out in the presence of a catalyst, of formula
- What?
where R is an haloalkyl. Haloalkyl means an alkyl radical substituted by one or more halogen atoms. The alkyl radical consists of 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms. The halogen atom is chosen from F, Cl, Br and I. For example, the haloalkyl is C2F6 or CF3.
The initiator of the reaction is a polyol with 3 to 6 hydroxyl functions, i.e. the initiator is an organic molecule with 3 to 6 -OH functions. The polyol as defined in the present invention may be an aliphatic or cyclic carbon chain. The polyol may also contain other organic functions, such as one or more aldehyde and/or ketone functions. For example, the polyol may be chosen from glycerol, trimethyl ether, trimethyl trioctane, pentaethyl taltrol, dipropyl sorthritol, sorbitol, xylitol, mannitol, penethyl sorthritol, dipropyl sorthritol, dipropyl sulphate, mannitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol, tribitol
Err1:Expecting ',' delimiter: line 1 column 88 (char 87)
The reaction temperature is chosen to be below the degradation temperature of the polymer formed. For example, the temperature is 0-150°C. Preferably the temperature is 10-90°C. Preferably the temperature is 20-45°C, preferably 20-30°C. For example, the reaction is performed at room temperature.
Preferably, the reaction is stopped once the desired degree of polymerization is achieved. For example, the reaction is stopped when the consumption of the initial monomer is 90 to 100 percent. Preferably, the reaction is stopped when the consumption of the initial monomer is more than 94 percent. For example, the reaction is stopped by tempering. Alternatively, the reaction is stopped by adding a base. For example, the polymerization reaction is stopped by adding a basic resin, such as by AmberlystTM A21.
Preferably, the ratio of the initial monomer concentration to the OH concentration of the starter is 200/1 to 1/1, more preferably 100/1 to 3/1, even more preferably 20/1 to 4/1.
Preferably, the initial catalyst concentration to the OH concentration of the starter is 0.1 to 20, more preferably 0.2 to 10, and even more preferably 0.2 and 6.
The process has many advantages. In particular, the process is easily controllable. It is more efficient than the previous state-of-the-art processes. In particular, the polymers obtained are functionalized on all branches of the star. This is also true when synthesizing oligomers.
Unless otherwise defined, all technical and scientific terms used in this application shall have the same meaning as is commonly understood by a specialist in the field to which the invention relates.
The following examples are presented to illustrate the invention and should in no way be considered as limiting the scope of the invention.
In the following examples and unless otherwise stated, the following polymerization conditions apply: trimethyl propane (TMP) is used after azootropic distillation in toluene, pentaerythritol (PET) is vacuum dried in the presence of P2O5, and glycerol is distilled. Unless otherwise stated, the lactid is used in its racemic form (D,L) in dichloromethane ([L]0 = 1 mol/L), in the presence of 0.1 equivalent of trifluoromethane sulfonic acid per alcohol. Unless otherwise stated, polymerizations are performed at room temperature (T = 26°C) at high excitation. The polymers are agitated in a linear reaction time of approximately 5-7 hours (approximately 5-7 hours) from their starting points.
At the end of the reaction, the catalyst is neutralized by the basic resin AmberlystTM A21. The polymers are precipitated into a mixture of CH2Cl2/heptane and then vacuum dried in a rotary evaporator for 48 h.
- What?
| Polyol | Analyse Elémentaire | Heptane | |||||||
| TMP | 1/9/0,3 | 2054* | 1,15 | 2,8 | 3/3 | - | - | ||
| TMP | 1/6/0,3 | 1452 | 1,15 | 1,95 | 2,9/3 | F = 79 ppm | 1,22% | 0,79% | |
| S = 42 ppm | |||||||||
| PET | 1/7,8/ 0,4 | 1689 | 1,26 | 1,8 | 3,7/4 | F = 39 ppm | 1,87% | 0,87% | |
| S = 28 ppm | |||||||||
| Glycérol | 1/6/0,3 | 1516 | 1,12 | 1,95 | 2,9/3 | F = 58 ppm | 0,03% | 0,13% | |
| S = 21 ppm |
| * 91 % conversion - Tg = 7° C |
For a lactide/starter ratio (starter = trimethyl propane) of 3/1, a white and hard polymer is obtained (Tg = 7°C).
For a ratio of 2/1 (i.e. a lactide/[OH]0 ratio of 6/1 for trimethyl propane), the pentaerythritol-amorph polymer is quite hard, whereas the glycerol-amorph polymer is the most fluid of the three (vitreous transition temperature Tg = 3° C).
Even at this monomer/amorcer ratio, well-controlled polymers are obtained (DPRMN (degree of polymerization measured by NMR) by a close arm to the theoretical DP (degree of polymerization) of 2, polymorphism index around 1.2) with good amortization on all alcohols: for triols, 2.9 CH2 out of 3 have been amortized. This measurement is determined by NMR 1H spectroscopy on the integration of CH2-O-PLA (and CH-O-PLA for glycol) with respect to signals observed around 3.5 ppm (characteristic region of CH2-OH and CH-OH of the amortizers).
The lactide (LA) and the protic starter (polyol, 1 equivalent) are dissolved in freshly distilled dichloromethane ([LA]0 = 1 mol.L-1).
4 equivalents (in relation to trifluoric acid) of Amberlyst A21 resin (4.6 μg/g) are added, which is dried on P2O5. The reaction medium is stirred for 45 minutes and then filtered. Twice, 2 equivalents of Amberlyst A21 resin are added to the reaction medium which is stirred for 45 minutes and then filtered. The reaction solvent is then evaporated under vacuum and the resulting polymer precipitated with a mixture of CH2Cl2/Heptane 5/90. The surfactant is removed and the polymer is vacuum dried at 60°C for 48 hours.
The mean value of the measurement is calculated as the sum of the measurements of the two samples taken at the same time.
The measurement of the concentration of the test chemical in the feed additive shall be carried out in accordance with the following equation:
The DPRMN is 4.5
% of residual lactate (HPLC): 0,6%
The following information shall be provided for the purpose of the calculation of the emission factor:
The mean value of the measurement is calculated as the sum of the measurements of the two samples taken at the same time.
% of residual lactate (HPLC): 0,6%
The DPRMN is 5.9
The following information shall be provided for the purpose of the calculation of the emission factor:
The concentration of the active substance in the feed additive shall be calculated as follows:
The DPRMN is 8.4
The following information is provided for the purpose of this Regulation:
In the following examples 8 to 10, trimethylolethane was chosen as the starter. For all polymerizations, trimethylolethane is used after sublimation. Lactid is used either in racemic (D,L) or enantiopure (L) form.
The length of the polymer is dependent on the initial ratio [Monomer M]0/[Amorphant I]0. Different ratios [M]0/[I]0 are set for each polymerization in order to obtain polymers of varying masses.
- What?
| Ex | Lactide | Temps | Conversion | |||||
| 8 | 30/1/3 | 1h30 | 96% | 5292 | 1,25 | 7,5 | 3/3 | |
| 9 | 50/1/3 | 3h | 94% | 10108 | 1,10 | 14 | 3/3 | |
| 10 | 100/1/3 | 7h30 | 96% | 17934 | 1,17 | 30 | 3/3 |
The incorporation of the starter CH2OH is complete (controlled by 1H NMR spectroscopy) for each polymer.
Furthermore, it is observed that the higher the ratio, the greater the mass of the polymer obtained.
The lactid and polyol (1 equivalent) are dissolved in freshly distilled dichloromethane ([LA]0 = 1 mol.L-1). Triflic acid (1 equivalent per OH) is then added and the reaction medium is stirred vigorously at T = 26°C until total consumption of the lactid, controlled by 1H NMR spectroscopy. At the end of polymerization, 4 equivalents (relative to triflic acid) of Amberlyst A21 resin (4.6 μg/g), previously dried on P2O5, are added. The reaction agent is filtered.
A star-shaped PLGA copolymer with a lactide/glycolide ratio of 80/20 is synthesised from trimethylolethane.
| Ex | Temps | Conversion | |||||
| 11 | 9/1/0,3 | 5h | 95% | 1898 | 1,16 | 3 | 3/3 |
After 5 h of agitation, the glycolide is completely consumed and there is little residual lactide. The DPRMN per arm is close to the theoretical DP (equal to 3) and the 1H NMR spectroscopy confirms that initiation has occurred on all trimethylolethane alcohols.
The lactide (7.8 equivalents), glycolide (1.2 equivalents) and polyol (1 equivalent) are suspended in freshly distilled dichloromethane ([LA]0 = 1 mol.L-1). Trifluoric acid (0.1 equivalent per OH) is then added and the reaction medium is stirred vigorously at T = 26°C until total consumption of the lactide, then controlled by 1H NMR spectroscopy. At the end of polymerization, 4 equivalents (relative to trifluoric acid) of Amberlyst21 A resin (4.6 μg/min), previously dried to P2O5, are added. The reaction is stirred for 45 minutes filtered.
The mean of the measurements is calculated as the mean of the measurements of the two samples.
The DPRMN is 8.95
The following table shows the results of the analysis of the test chemical:
The following table shows the data for the calculation of the average of the values of the emissions of the product concerned during the period considered:
In this example, toluene is used as a solvent after distillation and the reaction mixture is heated to 80°C.
- What?
| Ex | Temps | Conversion | |||||
| 12 | 9/1/0,3 | 30 min | 97 % | 2284 | 1,25 | 3 | 3/3 |
The lactid (LA) and the protic starter (polyol, 1 equivalent) are suspended in freshly distilled toluene ([LA]0 = 1 mol.L-1) and the reaction medium is heated to 80°C under argon atmosphere. Trifluoric acid (0.1 OH equivalent) is then added and the reaction medium is stirred vigorously at T = 26°C for 30 minutes (total consumption of the lactid, then controlled by 1H NMR spectroscopy). 4 equivalents (relative to trifluoric acid) of pre-Amberlyst A21 (4.6 μg/g), resalably dried on P2O5, are reacted. The reaction medium is heated for 45 minutes at room temperature to filtered solvent. The reaction medium is then evaporated.
The analytical data of the polymer thus obtained are similar to those of example 1.
Dipentaerythritol is vacuum-dried in the presence of P2O5 and the lactid is used as an enantiopure (L) in dichloromethane ([LA]0 = 1 mol/L), in the presence of 0.1 trifluoric acid equivalent per alcohol. Polymerizations are performed at room temperature.
| Ex | Temps | Conversion | |||||
| 13 | 18/1/0,6 | 8h30 | 94% | 4320 | 1,20 | 3,1 | 3/3 |
Even with a low monomer/amorcer ratio, the polymer obtained is well controlled: the DPRMN per arm is close to the theoretical DP (equal to 3) and by 1H NMR spectroscopy, the integration for 12H of CH2-O-PLA coupled with the absence of signal around 3.5 ppm (characteristic CH2-OH region of the amorcer) allows to state that the initiation on all alcohols of dipentaerythritol is complete.
The lactide (LA, 18 equivalents) and dipentaerythritol (1 equivalent) are suspended in freshly distilled dichloromethane ([LA]0 = 1 mol.L-1). Triphlic acid (0.05 equivalent per OH) is then added and the reaction medium is stirred vigorously at T = 26°C until total consumption of the lactide, controlled by 1H NMR spectroscopy.
Add 4 equivalents (in relation to trifluoric acid) of Amberlyst A21 resin (4.6 μg/g), previously dried on P2O5.
- What?
The mean of the measurements is calculated as the mean of the measurements of the two samples.
The following is the list of active substances that are to be used in the preparation of the active substance:
The number of samples shall be:
The following information shall be provided for each test chemical:
Claims (15)
- Method for preparing star polymers based on a lactide monomer and a glycolide monomer or a lactide monomer, by ring opening in the presence of a catalyst, characterized in that:- the catalyst has the formula in which R is a C1 to C6 haloalkyl;- the initiator is a polyol comprising from 3 to 6 hydroxyl functions.
- Method for preparing star polymers according to claim 1, in which the monomer is lactide.
- Method for preparing star polymers according to claim 1, in which the polymers are prepared based on a lactide monomer and a glycolide monomer.
- Method for preparing star polymers according to one of claims 1 to 3, in which the reaction takes place in an organic solvent, preferably in a halogenated or aromatic solvent.
- Method for preparing star polymers according to one of claims 1 to 4, in which the solvent is a halogenated solvent, preferably the solvent is dichloromethane.
- Method for preparing star polymers according to one of claims 1 to 5, in which the initiator is a polyol comprising from 3 to 4 hydroxyl functions.
- Method for preparing star polymers according to claim 6, in which the initiator is glycerol.
- Method for preparing star polymers according to one of claims 1 to 7, in which the catalyst is trifluoromethanesulphonic acid.
- Method for preparing star polymers according to one of claims 1 to 8, in which the reaction temperature is from 0 to 150°C, preferably from 20 to 45°C.
- Method for preparing star polymers according to one of claims 1 to 9, in which the initial monomer concentration/OH function concentration ratio of the initiator is from 200/1 to 1/1.
- Method for preparing star polymers according to claim 10, in which the initial monomer concentration/OH function concentration ratio of the initiator is from 100/1 to 2/1.
- Method for preparing star polymers according to claim 11, in which the initial monomer concentration/OH function concentration ratio of the initiator is from 20/1 to 4/1.
- Method for preparing star polymers according to one of claims 1 to 12, in which the initial catalyst concentration/OH function concentration ratio of the initiator is from 0.1 to 20.
- Method for preparing star polymers according to claim 13, in which the initial catalyst concentration/OH function concentration ratio of the initiator is from 0.2 to 10.
- Method for preparing star polymers according to claim 14, in which the initial catalyst concentration/OH function concentration ratio of the initiator is from 0.3 to 6.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR1004427 | 2010-11-15 | ||
| FR1004427A FR2967415B1 (en) | 2010-11-15 | 2010-11-15 | PROCESS FOR THE PREPARATION OF STAR POLYMERS |
| PCT/FR2011/000601 WO2012066194A2 (en) | 2010-11-15 | 2011-11-14 | Method for preparing star polymers |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| HK1189013A1 HK1189013A1 (en) | 2014-05-23 |
| HK1189013B true HK1189013B (en) | 2015-11-13 |
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