Nanoscale Morphology of Polyanhydride Copolymers

Kipper, Matthew J.; Hou, Shuhn-Shyurng; Seifert, Söenke; Thiyagarajan, P.; Schmidt‐Rohr, Klaus; Narasimhan, Balaji

doi:10.1021/ma051267r

Cited by 12 publications

(10 citation statements)

References 20 publications

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“…Faghihi et al 8 reported that random copolymers of butyl acrylate and methyl methacrylate showed nanophase segregation according to DMA, DSC and 13 C-NMR spin diffusion experiments. Kipper et al 9 reported that random copolymers of 1,6-bis(p-carboxyphenoxy)hexane and sebacic acid undergo microphase separation because of large differences in the segment-segment interaction parameters. In this study, the crude NBRs did not show a phase separation structure.…”

Section: Pulsed 1 H-nmr Analysis Of Crude Nbrsmentioning

confidence: 99%

“…Although almost all random copolymers show homogeneous morphology, it has been reported that some random copolymers show an inhomogeneous phase structure. 8,9 In the case of NBRs, the existence of phaseseparated structures was suggested by the spin-lattice relaxation time (T 1r ) analysis of CH 2 via the 13 C-NMR inversion recovery method. 10 According to these reports, the inhomogeneity was caused by an intramolecular inhomogeneous structure composed of segments with different monomer sequences and by large differences in the segmental interaction parameters.…”

Section: Introductionmentioning

confidence: 99%

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Nanoscale heterogeneous structure of polyacrylonitrile-co-butadiene with different molecular mobilities analyzed by spin–spin relaxation time

Ono

Fujiwara

Nishimura

2013

Polym J

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To identify components with different spin-spin relaxation times, T 2 , in the solid-echo pulse proton nuclear magnetic resonance (1 H-NMR) spectra of crude acrylonitrile (AN)-butadiene rubbers (NBRs) with five different AN contents, we tried to understand the inhomogeneity in the crude NBRs in terms of their microstructures and molecular mobilities. The results of small-angle X-ray scattering, differential scanning calorimetry and dynamic mechanical analysis showed that crude NBRs have a singlephase and homogeneous morphology on the nanoscale. The microstructure of the crude NBRs shows alternately copolymerized AN-butadiene (BU) and BU block sequences, as indicated by 1 H-NMR spectra. The T 2 of the crude NBRs revealed three components with different molecular mobilities, even in homogeneous samples. The content of the highest-mobility component with T 2l is negligible. Judging from the AN content dependence of the 1 H ratio of these components, the low-mobility component with T 2s and high-mobility component with T 2m were assigned to the alternately copolymerized AN-BU sequences and BU block sequences, respectively.

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Section: Pulsed 1 H-nmr Analysis Of Crude Nbrsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nanoscale heterogeneous structure of polyacrylonitrile-co-butadiene with different molecular mobilities analyzed by spin–spin relaxation time

Ono

Fujiwara

Nishimura

2013

Polym J

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“…For compositions richer in either monomer, the majority component sequence length greatly increased while the minority component remained moderate. Such divergence in number-average sequence length indicates a weak block-like microstructure . Following the same methodology, reactivity ratios were calculated for this library (Figure b).…”

Section: Resultsmentioning

confidence: 99%

“…Such divergence in numberaverage sequence length indicates a weak block-like microstructure. 25 Following the same methodology, reactivity ratios were calculated for this library (Figure 2b). At compositions between 20:80 and 80:20 CPTEG:SA, the reactivity ratios for both components were near unity.…”

Section: Polymermentioning

confidence: 99%

High-Throughput Synthesis and Screening of Rapidly Degrading Polyanhydride Nanoparticles

2020

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Combinatorial techniques can accelerate the discovery and development of polymeric nanodelivery devices by pairing high-throughput synthesis with rapid materials characterization. Biodegradable polyanhydrides demonstrate tunable release, high cellular internalization, and dose sparing properties when used as nanodelivery devices. This nanoparticle platform shows promising potential for small molecule drug delivery, but the pace of understanding and rational design of these nanomedicines is limited by the low throughput of conventional characterization. This study reports the use of a highthroughput method to synthesize libraries of a newly synthesized, rapidly-eroding polyanhydride copolymer based on 1,8-bis(p-carboxyphenoxy)-3,6-dioxaoctane (CPTEG) and sebacic acid (SA) monomers. The high-throughput method enabled efficient screening of copolymer microstructure, revealing weak block-type and alternating architectures. The high-throughput method was adapted to synthesize nanoparticle libraries encapsulating hydrophobic model drugs. Drug release from these nanoparticles was rapid, with a majority of the payload released within three days. Drug release was dramatically slowed at acidic pH, which could be useful for oral drug delivery. Rhodamine B (RhoB) release kinetics generally followed patterns of polymer erosion kinetics, while Coomassie brilliant blue (CBB) released the fastest from the slowest degrading polymer chemistry and vice versa. These differences in trends between copolymer chemistry and release kinetics were hypothesized to arise from differences in mixing thermodynamics. A high-throughput method was developed to synthesize polymerdrug film libraries and characterize mixing thermodynamics by melting point depression. Rhodamine B had a negative χ for all copolymers tested, indicating a tendency toward miscibility. By contrast, CBB χ increased, eventually becoming positive, with increasing CPTEG content. This indicates an increasing tendency toward phase separation in CPTEG-rich copolymers. These in vitro results screening polymerdrug interactions showed good agreement with in silico predictions from Hansen solubility parameter estimation and were able to explain the observed differences in model drug release trends. ABSTRACTCombinatorial techniques can accelerate the discovery and development of polymeric nanodelivery devices by pairing high-throughput synthesis with rapid materials characterization.Biodegradable polyanhydrides demonstrate tunable release, high cellular internalization, and dose sparing properties when used as nanodelivery devices. This nanoparticle platform shows promising potential for small molecule drug delivery, but the pace of understanding and rational design of these nanomedicines is limited by the low throughput of conventional characterization.This study reports the use of a high-throughput method to synthesize libraries of a newly synthesized, rapidly-eroding polyanhydride copolymer based on 1,8-bis(p-carboxyphenoxy)-3,6-dioxaoctane (CPTEG) and sebacic acid (SA) monomers. T...

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“…Information from the blend phase behavior, such as the Flory-Huggins parameter and phase transitions, can be used to describe microphase separation in block or weakly segregated random copolymers. 2,3 This microstructure of the polymer may play an important role in the release kinetics of drugs from these polymers. 4 The present study is focused on the miscibility of blends based on the biodegradable polyanhydride homopolymers composed of 1,6-bis(p-carboxyphenoxy)hexane (CPH) and sebacic acid (SA) (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

Combinatorial/High Throughput Methods for the Determination of Polyanhydride Phase Behavior

Thorstenson¹,

Petersen²,

Narasimhan³

2009

J. Comb. Chem.

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Combinatorial methods have been developed to study the phase behavior of biodegradable polyanhydrides for drug delivery applications. The polyanhydrides of interest are poly [l,6-bis(p-carboxyphenoxy) hexane] (CPH) and poly[sebacic anhydride] (SA). Both continuous and discrete polymer blend libraries were fabricated by using a combination of solution-based gradient deposition and rapid prototyping. Blend compositions were characterized via a high throughput transmission Fourier transform infrared (FTIR) sampling technique and compared against theoretical mass balance predictions. To obtain phase diagrams of CPH/S A, the effect of blend composition and annealing temperature on the miscibility of the blend was studied. This gradient library was observed with optical microscopy in order to determine cloud points. These results were compared with a theoretical phase diagram obtained from Flory-Huggins theory and with atomic force microscopy (AFM) experiments on blend libraries and the agreement between the methods was very good. The high throughput method demonstrates that the CPH/SA system exhibits upper critical solution temperature behavior. These libraries are amenable to other high throughput applications in biomaterials science including cell viability, cell activation, and protein/biomaterial interactions.Keywords atomic force microscopy, chemistry, drug delivery system, infrared spectroscopy, nuclear magnetic resonance spectroscopy, polyanhydrides . Both continuous and discrete polymer blend libraries were fabricated by using a combination of solution-based gradient deposition and rapid prototyping. Blend compositions were characterized via a high throughput transmission Fourier transform infrared (FTIR) sampling technique and compared against theoretical mass balance predictions. To obtain phase diagrams of CPH/SA, the effect of blend composition and annealing temperature on the miscibility of the blend was studied. This gradient library was observed with optical microscopy in order to determine cloud points. These results were compared with a theoretical phase diagram obtained from Flory-Huggins theory and with atomic force microscopy (AFM) experiments on blend libraries and the agreement between the methods was very good. The high throughput method demonstrates that the CPH/SA system exhibits upper critical solution temperature behavior. These libraries are amenable to other high throughput applications in biomaterials science including cell viability, cell activation, and protein/biomaterial interactions.

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Nanoscale Morphology of Polyanhydride Copolymers

Cited by 12 publications

References 20 publications

Nanoscale heterogeneous structure of polyacrylonitrile-co-butadiene with different molecular mobilities analyzed by spin–spin relaxation time

Nanoscale heterogeneous structure of polyacrylonitrile-co-butadiene with different molecular mobilities analyzed by spin–spin relaxation time

High-Throughput Synthesis and Screening of Rapidly Degrading Polyanhydride Nanoparticles

Combinatorial/High Throughput Methods for the Determination of Polyanhydride Phase Behavior

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