Tyrosine‐derived polycarbonates: Backbone‐modified “pseudo”‐poly(amino acids) designed for biomedical applications

Pulapura, Satish; Kohn, Joachim

doi:10.1002/bip.360320418

Cited by 103 publications

(65 citation statements)

References 10 publications

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“…Among these polymers, collagen is the best known tissue-derived natural polymer and has been used as tissue-culture scaffolds. However, the practical problems with collagen are its cost, and a limited range of physical properties unless extensively crosslinked, which alters biological response [7,8]. Silk fibroin (SF), used as an appealing alternative polymer, possesses impressive mechanical properties and appreciable bioactivity that make it attractive for artificial bones [9,10].…”

Section: Introductionmentioning

confidence: 99%

Effect of polyaspartic acid on hydroxyapatite deposition in silk fibroin blend films

L.¹,

Li²,

Ru³

et al. 2010

Express Polym. Lett.

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Abstract. Polyaspartic acid/silk fibroin/hydroxyapatite (PASP/SF-HA) composites have been synthesized by biomimetic processing. SF solution was mixed with different contents of PASP to prepare the PASP/SF blend membranes. After ethanol treatment and premineralization process, the blend membranes were immersed into 1.5 simulated body fluid (1.5 SBF) for 24 h to induce apatite deposition at 37±0.5°C. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results revealed that a conformation transition of SF occurred after the addition of PASP and ethanol treatment. The FTIR and XRD results also confirmed that the main component of apatite deposition was HA. Scanning electron microscopy (SEM) showed that the content of HA increased with increasing PASP concentration .Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP) results revealed that the Ca/P molar ratio could reach 1.45, which was close to the Ca/P ratio of apatite. It was appropriate to conclude that the increasing content of PASP had a distinct effect on HA deposition in the blend films.

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Section: Introductionmentioning

confidence: 99%

Effect of polyaspartic acid on hydroxyapatite deposition in silk fibroin blend films

L.¹,

Li²,

Ru³

et al. 2010

Express Polym. Lett.

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“…Copolymers of PTMC were synthesized for adapting to applications requiring different degradation rates and mechanical properties. 10,[26][27][28][29] Pendant hydroxyl groups have been introduced to improve the hydrophilicity and hence the degradability. 30 Since end groups have special effect on degradation rate, end-group functionalized polycarbonates will have different degradation rate.…”

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confidence: 99%

Synthesis, Characterization, and Degradation Behaviors of End-Group-Functionalized Poly(trimethylene carbonate)s

Zhuo

2003

Polym J

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KEY WORDSPolycarbonate / Biodegradable Material / End-Group Effect / Biodegradable polymers are under investigation for biomedical, pharmaceutical applications, etc. Degradability is one of their important characters. Many factors affect the degradation rate. Besides environmental conditions, such as temperature, the degradation rate is strongly dependent on the film thickness, 1 additives such as monomer, 2 basic compounds, 3 acid drugs 4 or superoxide ion, 5 and catalyst such as SnOct 2 or zinc metal, 6-9 etc. The molecular architecture, 10-13 hydrophilicity, 14-16 reasonable crosslink, 17,18 and surface modification 19,20 have vital influence on the degradation properties, too.End-group effect is demonstrable on the degradation rate. 21 It was shown that poly(lactide-co-glicolide) (PLGA) with a free carboxyl group at the polymer terminus (uncapped PLGA) degrades faster than PLGA with a hydrophobic alkyl ester linkage at the polymer terminus (capped PLGA). 22 Lee 21 synthesized various end-group-functionalized, such as OH-, NH 2 -, Cl-, or COOH-terminated polylactides (PLAs) and found that the COOH end group plays a crucial role in the hydrolysis degradation in both alkaline and acidic medium. Protection of OH end group results in a substantial retarded degradation. 23 Polyanhydrides capped with fatty terminals also show a significantly slow degradation and drug release rate. 24 Linear aliphatic polycarbonates, such as poly(1,3-trimethylene carbonate) (PTMC), have been shown to be potential for use as medical implants and for drugdelivery applications. 25 But they degrade unexpectedly slow. 10 Many efforts have been made to enhance their degradation rate. Copolymers of PTMC were synthesized for adapting to applications requiring different degradation rates and mechanical properties. 10,[26][27][28][29] Pendant hydroxyl groups have been introduced to improve the hydrophilicity and hence the degradability. 30 Since end groups have special effect on degradation rate, end-group functionalized polycarbonates will have different degradation rate. Because the polymers of multiarm architecture have a higher end-group concentration than linear polymers of the same molecular weights, the multiarm structure can strengthen the end group effect. Some researchers have synthesized the OH-terminated PTMC by ring-opening polymerization (ROP), but the degradability has not been involved up to now. 31 In the present study, we synthesize PTMC with different number of arms terminated by hydroxyl group or carboxylic group and study the degradability of such end-group-functionalized PTMCs preliminarily. EXPERIMENTAL 1,3-Trimethylene carbonate (TMC) was synthesized according to the reported method. 32 All other regents were treated just before use. Synthesis of OH-Terminated PTMC (OH-PTMC)The ring-opening polymerizations (ROP) of TMC initiated by alcohols are illustrated in Scheme 1. These polymerization reactions were carried out in the melt bulk. All reaction reagents were used just after treated. A known amount of TMC was charged ...

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“…Pyridine 99+% was purchased from Acros (Morris Plains, NJ; poly(ethylene glycol) 1000 (PEG1K) and bis(trichloromethyl) carbonate were purchased from Fluka Tyrosine-PEG-derived poly(ether carbonate)s were prepared as previously described [35,40] and their general structure is shown in Figure 1. The copolymers are comprised of poly(ethylene glycol) of 1,000 Da molecular weight (PEG1K) and desaminotyrosyl tyrosine alkyl ester monomers (DTR), where R is the pendent ester; DTO is desaminotyrosyl tyrosine octyl ester and DTE is desaminotyrosyl tyrosine ethyl ester.…”

Section: Copolymer Synthesismentioning

confidence: 99%

“…The molecular weights of the copolymers were measured by gel permeation chromatography (GPC) using THF as eluent [40] (see Table 1). …”

Section: Copolymer Synthesismentioning

confidence: 99%

Polymer–xerogel composites for controlled release wound dressings

Costache¹,

Qu²,

Ducheyne³

et al. 2010

Biomaterials

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Many polymers and composites have been used to prepare active wound dressings. These materials have typically exhibited potentially toxic burst release of the drugs within the first few hours followed by a much slower, potentially ineffective drug release rate thereafter. Many of these materials also degraded to produce inflammatory and cytotoxic products. To overcome these limitations, composite active wound dressings were prepared here from two fully biodegradable and tissue compatible components, silicon oxide sol-gel (xerogel) microparticles that were embedded in tyrosine-poly(ethylene glycol)-derived poly(ether carbonate) copolymer matrices. Sustained, controlled release of drugs from these composites was demonstrated in vitro using bupivacaine and mepivacaine, two water-soluble local anesthetics commonly used in clinical applications. By systematically varying independent compositional parameters of the composites, including the hydrophilic:hydrophobic balance of the tyrosine-derived monomers and poly(ethylene glycol) in the copolymers and the porosity, weight ratio and drug content of the xerogels, drug release kinetics approaching zero-order were obtained. Composites with xerogel mass fractions up to 75% and drug payloads as high as 13% by weight in the final material were fabricated without compromising the physical integrity or the controlled release kinetics. The copolymer-xerogel composites thus provided a unique solution for the sustained delivery of therapeutic agents from tissue compatible wound dressings. These materials have typically exhibited potentially toxic burst release of the drugs within the first few hours followed by a much slower, potentially ineffective drug release rate thereafter. Many of these materials also degraded to produce inflammatory and cytotoxic products. To overcome these limitations, composite active wound dressings were prepared here from two fully biodegradable and tissue compatible components, silicon oxide sol-gel (xerogel) microparticles that were embedded in tyrosinepoly(ethylene glycol)-derived poly(ether carbonate) copolymer matrices. Sustained, controlled release of drugs from these composites was demonstrated in vitro using bupivacaine and mepivacaine, two water-soluble local anesthetics commonly used in clinical applications. By systematically varying independent compositional parameters of the composites, including the hydrophilic:hydrophobic balance of the tyrosine-derived monomers and the poly(ethylene glycol) in the copolymers and the porosity, weight ratio and drug content of the xerogels, drug release kinetics approaching zero-order were obtained. Composites with xerogel mass fractions up to 75% and drug payloads as high as 13% by weight in the final material were fabricated without compromising the physical integrity or the controlled release kinetics. The copolymer -xerogel composites thus provided a unique solution for the sustained delivery of therapeutic agents from tissue compatible wound dressings.2

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Tyrosine‐derived polycarbonates: Backbone‐modified “pseudo”‐poly(amino acids) designed for biomedical applications

Cited by 103 publications

References 10 publications

Effect of polyaspartic acid on hydroxyapatite deposition in silk fibroin blend films

Effect of polyaspartic acid on hydroxyapatite deposition in silk fibroin blend films

Synthesis, Characterization, and Degradation Behaviors of End-Group-Functionalized Poly(trimethylene carbonate)s

Polymer–xerogel composites for controlled release wound dressings

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