Biodegradable polymer systems for the sustained release of polypeptides

Hutchinson, F.; Furr, B. J. A.

doi:10.1016/0168-3659(90)90018-o

Cited by 122 publications

(36 citation statements)

References 16 publications

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“…Poly(DL-lactide-co-glycolide) polymers (PLGAs) are among the biodegradable materials which have been most successfully used in medical applications [1][2][3][4] such as sutures, bone implants, and drug delivery systems. For the case of drug delivery systems, therapeutic agents have been formulated into PLGA microspheres, disks, and rods.…”

Section: Introductionmentioning

confidence: 99%

Effects of metal salts on poly(DL-lactide-co-glycolide) polymer hydrolysis

Zhang

Zale

Sawyer

et al. 1997

J. Biomed. Mater. Res.

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The effects of encapsulated metal salts on poly(DL-lactide-co-glycolide) (PLGA) water uptake and degradation properties were investigated in this work. Salts of varying aqueous solubility characteristics were incorporated into PLGA films either as particles or by codissolution in polymer solutions. Polymer films were characterized with respect to the kinetics of water uptake, morphology changes, degradation, and weight loss after hydration. It was found that these properties are strongly influenced by the presence and nature of encapsulated salts. Effects range from minor changes in water uptake profile with no significant difference in degradation kinetics to major alterations in water uptake kinetics together with a several-fold decrease in the polymer degradation rate. Possible mechanistic explanations for the observed effects are discussed.

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Section: Introductionmentioning

confidence: 99%

Effects of metal salts on poly(DL-lactide-co-glycolide) polymer hydrolysis

Zhang

Zale

Sawyer

et al. 1997

J. Biomed. Mater. Res.

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“…These interactions are dependent on protein M W ; isoelectric point; amino acid composition; and hydrophobicity, as well as polymer M W and chemistry 1 . Polymer properties such as M W , copolymer composition and crystallinity can also be tailored to alter polymer degradation and subsequent drug release profiles 7,8 . For example, an increase in the M W of Poly(lactic-co-glycolic acid) (PLGA) resulted in longer degradation times and slower release of bovine serum albumin and tetanus toxid 9,10 .…”

Section: Introductionmentioning

confidence: 99%

Evaluation of biodegradable polyester-co-lactone microparticles for protein delivery

Tawfeek

Khidr

Samy

et al. 2013

Drug Development and Industrial Pharmacy

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“…24,[27][28][29][30] The main advantages of PLGA are biodegradability, nonimmunogenicity, and acceptable mechanical strength. Other benefits of using PLGA include ease of implant fabrication and the ability to adjust degradation and release rates by changing copolymer composition, starting molecular weight, and film thickness.…”

Section: Materials Selectedmentioning

confidence: 99%

Effects of cyclical mechanical stress on the controlled release of proteins from a biodegradable polymer implant

Tencer

1997

J. Biomed. Mater. Res.

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The availability of osteogenic proteins for orthopedic applications has led to great interest in developing delivery systems for these substances. Standard release rate models are applicable in most biological settings, but orthopedic implants usually bear mechanical loads. To determine whether a release rate model for load bearing applications must consider mechanical stress, the effects of dynamic mechanical stress on the in vitro release kinetics of two model proteins, bovine albumin (BA) and trypsin inhibitor (TI), from a biodegradable film were evaluated. Biodegradable poly(lacticco-glycolic acid) cylindrical implants with embedded proteins were subjected to cyclic three point bending loading of 720 cycles/day at 0.4 Hz for 2 weeks. Protein release into solution, swelling and mass loss changes, molecular weight degradation, and the presence of microstructural stress cracks and pores in the polymer carrier were evaluated. Cumulative BA and TI releases with time were significantly higher when a cyclic bending load was applied and increased with the magnitude of the load. Mass loss was not significantly greater, nor was swelling or molecular weight change of the polymer carrier in this 2-week interval. Pores on the surface of the polymer in the highest stress region were elongated into cracks, compared with pores in the low-stress region of the same implant, which were roughly circular. This implies that the pores probably act as stress risers to initiate cracks, which then expose more surface area, increasing protein release.

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Biodegradable polymer systems for the sustained release of polypeptides

Cited by 122 publications

References 16 publications

Effects of metal salts on poly(DL-lactide-co-glycolide) polymer hydrolysis

Effects of metal salts on poly(DL-lactide-co-glycolide) polymer hydrolysis

Evaluation of biodegradable polyester-co-lactone microparticles for protein delivery

Effects of cyclical mechanical stress on the controlled release of proteins from a biodegradable polymer implant

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