Synthesis of polylactides in the presence of co-initiators with different numbers of hydroxyl groups

Korhonen, Harri; Helminen, Antti; Seppälä, Jukka

doi:10.1016/s0032-3861(01)00150-1

Cited by 152 publications

(136 citation statements)

References 26 publications

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“…Pentaerythritol has been successfully employed as a multifunctional initiator for the bulk polymerization of lactides [22][23][24] , but in pilot experiments we noticed that polyols with higher functionality such as dipentaerythritol and tripentaerythritol (respectively 6 and 8 OH/molecule) were completely insoluble in the monomer. We therefore chose polymerization in a hydrophobic and easy to dry solvent such as toluene, where both pentaerythritol and dipentaerythritol are soluble; tripentaerythritol is only partially soluble and its use as an initiator in refluxing toluene yielded PDLLA with large batch-to-batch variations (although with consistent conversion: 78- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 82%), thus it was not further employed in this study.…”

Section: Synthesis Of Linear and Star Pdlla And Film Preparationmentioning

confidence: 99%

The Effect of Branching (Star Architecture) on Poly(d,l-lactide) (PDLLA) Degradation and Drug Delivery

et al. 2017

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This study focuses on the comparative evaluation of star (branched) and linear poly(L,D-lactic acid) (PDLLA) as degradable materials employed in controlled release.The polymers were prepared via ring-opening polymerization initiated by decanol (linear), pentaerythritol (4-armed star) and dipentaerythritol (6-armed star), and processed both in the form of films and nanoparticles. Independently on the length or number of their arms, star polymers degrade slower than linear polymers, possibly through a surface (vs. bulk) mechanism Further, the release of a model drug (atorvastatin) followed a zero-order-like kinetics for the branched polymers, and a first order kinetics for linear PDLLA. Using NHOst osteoblastic cells, both linear and star polymers were devoid of any significant toxicity and released atorvastatin in a bioavailable form; cell adhesion was considerably lower on star polymer films, and the slower release from their nanoparticles appeared to be beneficial to avoid atorvastatin overdosing.

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Section: Synthesis Of Linear and Star Pdlla And Film Preparationmentioning

confidence: 99%

The Effect of Branching (Star Architecture) on Poly(d,l-lactide) (PDLLA) Degradation and Drug Delivery

et al. 2017

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“…1 H NMR results, monomer ratio, arm length, number of hydroxyl group, and molecular weight could be calculated from the integral peaks [13]. From the peak area integrations, the copolymer compositions can be determined as showed in Table 3.…”

Section: Frommentioning

confidence: 99%

“…However, the actual chain length of the six-arm P(LA-co-CL) (CO-SB) was larger than the theoretical value. This was probably due to the lower activity of the secondary OH groups [13].…”

Section: Frommentioning

confidence: 99%

Low Molecular Weight Poly(Lactide-<i>co</i>-Caprolactone) for Tissue Adhesion and Tetracycline Hydrochloride Controlled Release in Wound Management

Sriputtirat¹,

Boonkong²,

Pengprecha³

et al. 2012

ACES

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The use of biopolymers as bioadhesives for human tissue is becoming a preferred alternative to suturing due to their superior adhesive, biocompatible, and biodegradable properties. In this work, low molecular weight poly(L-lactide-co--caprolactone) (P(LA-co-CL) was synthesized to achieve the glass transition temperature (T g ) of the copolymer at ambient temperature so that during application on the skin, the copolymer when combined with chitosan (CHI) into the CHI/P(LA-co-CL) film could provide the strong support at the injury site. Using alcohols with different numbers of hydroxyl groups as the co-initiator in polymerization provided the distinctive characteristics of copolymers. Among all copolymers synthesized, P(LA-co-CL) copolymer using pentaerythritol as the co-initiator when combined with CHI at the ratio of copolymer/CHI at 70/30 yielded the good film properties in tissue adhesion and tetracycline hydrochloride release.

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“…Korhonen et al have synthesized and characterized star-shaped PLAs with 1, 2, 4, 6 and 10 arms [13]. Srisa-ard et al have analysed influences of arm numbers (1, 4, 6 and 16) and length on the thermal properties [14].…”

Section: Introductionmentioning

confidence: 99%

Influence of macromolecular structure of novel 2- and 4-armed polylactides on their physicochemical properties and in vitro degradation process

Choińska

Muroya²,

Święszkowski

et al. 2016

J Polym Res

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The objective of this study was to analyse how macromolecular structure of polylactides influences their properties and degradation rate. To achieve this, novel 2-and 4-armed PDLLA and PLLA (noted as 2b and 4b) were synthesized by ring-opening method. 1,4-butanediol and pentaerythritol were used as initiators and stannous octoate was used as catalyst. The obtained polymers were investigated in terms of molecular weight by size exclusion chromatography, thermal properties by differential scanning calorimetry and thermogravimetry, and hydrophilicity by the contact angle measurements. The in vitro degradation test was carried out in PBS solution at 37°C by means of the mass loss, water uptake, molecular weight and thermal properties changes. The branched polylactides including 2bPDLLA, 4bPDLLA, 2bPLLA and 4bPLLA were successfully synthesized and the average molecular weights were around 40-45 kDa. The numbers of arms in each polymer just slightly influenced the thermal properties and the contact angle. The crystallinity of 4bPLLA was 23 %, whereas for 2bPLLA it was 41 %. The degradation rates of both 2b and 4bPLLA were similar and the degradation process was similar only during first 7 weeks. After this period, the degradation rate of 4bPDLLA increased. Consequently, thermal properties and degradation profiles of the branched polymers would depend on plural factors, such as chain length and crystallinity in branched structure.

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Synthesis of polylactides in the presence of co-initiators with different numbers of hydroxyl groups

Cited by 152 publications

References 26 publications

The Effect of Branching (Star Architecture) on Poly(d,l-lactide) (PDLLA) Degradation and Drug Delivery

The Effect of Branching (Star Architecture) on Poly(d,l-lactide) (PDLLA) Degradation and Drug Delivery

Low Molecular Weight Poly(Lactide-<i>co</i>-Caprolactone) for Tissue Adhesion and Tetracycline Hydrochloride Controlled Release in Wound Management

Influence of macromolecular structure of novel 2- and 4-armed polylactides on their physicochemical properties and in vitro degradation process

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Synthesis of polylactides in the presence of co-initiators with different numbers of hydroxyl groups

Cited by 152 publications

References 26 publications

The Effect of Branching (Star Architecture) on Poly(d,l-lactide) (PDLLA) Degradation and Drug Delivery

The Effect of Branching (Star Architecture) on Poly(d,l-lactide) (PDLLA) Degradation and Drug Delivery

Low Molecular Weight Poly(Lactide-&lt;i&gt;co&lt;/i&gt;-Caprolactone) for Tissue Adhesion and Tetracycline Hydrochloride Controlled Release in Wound Management

Influence of macromolecular structure of novel 2- and 4-armed polylactides on their physicochemical properties and in vitro degradation process

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Product

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Low Molecular Weight Poly(Lactide-<i>co</i>-Caprolactone) for Tissue Adhesion and Tetracycline Hydrochloride Controlled Release in Wound Management