The effect of γ-irradiation and polymer composition on the stability of PLG polymer and microspheres

Williams, Helen; Huxley, Jodanna; Claybourn, Mike; Booth, Jonathan; Hobbs, Matthew G.; Meehan, E. J.; Clark, Brian C.

doi:10.1016/j.polymdegradstab.2006.01.006

Cited by 28 publications

(13 citation statements)

References 29 publications

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“…By far the most frequently reported method for solid capsules involves γ–irradiation (Igartua et al 2008). Most reports highlight unfavorable dose-dependent polymer degradation, and the effects increase as glycolide content increases (Bittner et al 1999; Claybourn et al 2003; Hausberger et al 1995; Williams et al 2006). …”

Section: Discussionmentioning

confidence: 99%

Plasma Sterilization of Poly Lactic Acid Ultrasound Contrast Agents: Surface Modification and Implications for Drug Delivery

Eisenbrey

Hsu

Wheatley

2009

Ultrasound in Medicine & Biology

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Poly lactic acid (PLA) ultrasound contrast agents (CA) have been previously developed in our laboratory for ultrasound (US) imaging, as well as surface coated with doxorubicin to create a potential targeted platform of chemotherapeutic delivery using focused US. However, we have previously found it impossible to sterilize these agents while at the same time maintaining their acoustic properties, a task that would probably require fabrication within a clean facility. The purpose of this paper is to investigate the feasibility of using plasma to sterilize these CA while maintaining maximum echogenicity, a step that would greatly facilitate in vivo investigations. Effects of plasma exposure time (1, 3 and 6 minutes) and intensity (low- 10 mA, 6.8 W; medium- 15 mA, 10.5 W; and high- 25 mA, 18W) on the CA’s acoustic properties, surface morphology, zeta potential, capacity to carry chemotherapeutics, and overall sterility are described. Both increases in plasma intensity and exposure time increased CA zeta potential and also significantly increased drug payload. High intensity plasma exposure for three minutes was found to be an optimal sterilization protocol for maximal (100%) preservation of CA echogenicity. Plasma exposure resulted in sterile samples and maintained original CA enhancement of 20 dB and acoustic half-life over 75 minutes, while increasing CA zeta potential by 11 mV and doxorubicin loading efficiency by 10%. This study not only shows how a highly temperature and pressure sensitive agent can be sterilized using plasma, but also that surface modification can be used to increase surface binding of drug.

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Section: Discussionmentioning

confidence: 99%

Plasma Sterilization of Poly Lactic Acid Ultrasound Contrast Agents: Surface Modification and Implications for Drug Delivery

Eisenbrey

Hsu

Wheatley

2009

Ultrasound in Medicine & Biology

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“…Irradiation-based sterilization techniques such as gand e-beam sterilization are instantaneous, penetrating and nontoxic, but may be associated with changes in the molecular structure [55]. Irradiation, for instance, is known to reduce the glass temperature (T g ) and the molecular weight of PLG (80:20) and PCL (M w = 80 kDa) [56][57][58][59][60]. The molecular weight of PLG, which is known as a candidate material for SMP synthesis, decreases after g-irradiation, and this degradation process continues on storage for 4 weeks [57,58,61].…”

Section: Sterilization and In Vitro Cytotoxicity Testingmentioning

confidence: 99%

“…Irradiation, for instance, is known to reduce the glass temperature (T g ) and the molecular weight of PLG (80:20) and PCL (M w = 80 kDa) [56][57][58][59][60]. The molecular weight of PLG, which is known as a candidate material for SMP synthesis, decreases after g-irradiation, and this degradation process continues on storage for 4 weeks [57,58,61]. In addition, e-beam sterilization (50-200 kGy) is described to alter the degradation properties of PLG [57,61].…”

Section: Sterilization and In Vitro Cytotoxicity Testingmentioning

confidence: 99%

Shape-memory polymers as a technology platform for biomedical applications

Lendlein

Behl

Hiebl

et al. 2010

Expert Review of Medical Devices

407

285

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Polymeric materials are clinically required for medical devices, as well as controlled drug delivery systems. Depending on the application, the polymer has to provide suitable functionalities, for example, mechanical functions or the capability to actively move, so that an implant can be inserted in a compact shape through key-hole incisions and unfold to its functional shape in the body. Shape-memory polymers, as described herein regarding their general principle, compositions and architectures, have developed to a technology platform that allows the tailored design of such multifunctionality. In this way, defined movements of implants triggered either directly or indirectly, tailored mechanical properties, capability for sterilization, biodegradability, biocompatibility and controlled drug release can be realized. This comprehensive review of the scientific and patent literature illustrates that this technology enables the development of novel medical devices that will be clinically evaluated in the near future.

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“…Further, the PAEs are shown to be non-toxic in vitro [14] and in vivo [9, 16, 17] and, therefore, have great potential in various biomedical applications [6, 9, 13, 14, 17]. However, the polymer should meet the pharmacopeial and commercial requirement of sterility [18–21]. …”

Section: Introductionmentioning

confidence: 99%

“…E-beam and gamma radiations can also change the polymer properties by cross-linking the chains [19, 20]. Both forms of ionizing radiation have been shown to cause polymer cross-linking of a PLLA copolymer [21] and the corresponding homopolymers, PLLA, and PLGA [27, 30]. …”

Section: Introductionmentioning

confidence: 99%

Stability of a salicylate-based poly(anhydride-ester) to electron beam and gamma radiation

Rosario-Meléndez

Lavelle

Bodnar

et al. 2011

Polymer Degradation and Stability

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The effect of electron beam and gamma radiation on the physicochemical properties of a salicylate-based poly(anhydride-ester) was studied by exposing polymers to 0 (control), 25 and 50 kGy. After radiation exposure, salicylic acid release in vitro was monitored to assess any changes in drug release profiles. Molecular weight, glass transition temperature and decomposition temperature were evaluated for polymer chain scission and/or crosslinking as well as changes in thermal properties. Proton nuclear magnetic resonance and infrared spectroscopies were also used to determine polymer degradation and/or chain scission. In vitro cell studies were performed to identify cytocompatibility following radiation exposure. These studies demonstrate that the physicochemical properties of the polymer are not substantially affected by exposure to electron beam and gamma radiation.

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The effect of γ-irradiation and polymer composition on the stability of PLG polymer and microspheres

Cited by 28 publications

References 29 publications

Plasma Sterilization of Poly Lactic Acid Ultrasound Contrast Agents: Surface Modification and Implications for Drug Delivery

Plasma Sterilization of Poly Lactic Acid Ultrasound Contrast Agents: Surface Modification and Implications for Drug Delivery

Shape-memory polymers as a technology platform for biomedical applications

Stability of a salicylate-based poly(anhydride-ester) to electron beam and gamma radiation

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