Biotolerance of a semisolid hydrophobic biodegradable poly(ortho ester) for controlled drug delivery

Bernatchez, Stéphanie F.; Merkli, Alain; Tabatabay, C.; Gurny, Robert; Zhao, Qinghong; Anderson, James M.; Heller, Jorge

doi:10.1002/jbm.820270515

Cited by 24 publications

(11 citation statements)

References 12 publications

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“…9,10 Mixing hydrophobic drug and orthoester oligomer at high temperature and cooling the system followed by injection results in the formation of a gel. This is actually a gel injection rather than a sol to gel transition.…”

Section: Introductionmentioning

confidence: 99%

In situ gelation of PEG-PLGA-PEG triblock copolymer aqueous solutions and degradation thereof

Jeong

Bae

Kim

2000

J. Biomed. Mater. Res.

257

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Aqueous solutions of poly(ethylene glycol-b-[DL-lactic acid-co-glycolic acid]-b-ethylene glycol) (PEG-PLGA-PEG) triblock copolymers form a free-flowing sol at room temperature and become a gel at body temperature. In this study, in situ gel formation was investigated in rats. Upon subcutaneous injection of 33 wt % aqueous solutions of PEG-PLGA-PEG triblock copolymer into rats, transparent gels were observed. The gel showed good mechanical strength and the integrity of gels persisted longer than 1 month. The gel underwent degradation by hydrolysis and turned opaque. Degradation study showed preferential mass loss of PEG-rich segment from the in situ formed gel. Number average molecular weight determined by gel permeation chromatography decreased from 3300 to 1900 and 30% mass loss was observed over 1 month.

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Section: Introductionmentioning

confidence: 99%

In situ gelation of PEG-PLGA-PEG triblock copolymer aqueous solutions and degradation thereof

Jeong

Bae

Kim

2000

J. Biomed. Mater. Res.

257

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“…[5][6][7]16,22,24 However, these successive general steps have been reported in previous studies with other polymers such as poly(esters), poly(anhydrides), and poly(orthoesters). 18,[25][26][27][28] All these various polymers are considered as absorbable biocompatible materials.…”

Section: Discussionmentioning

confidence: 99%

Tissue reaction and biodegradation of implanted cross‐linked high amylose starch in rats

Désévaux

Dubreuil

Lenaerts

et al. 2002

J. Biomed. Mater. Res.

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The biocompatibility and degradation characteristics of cross-linked high amylose starch (Contramid were investigated in rats over 4 months. Contramid pellets (3-mm diameter and thickness) obtained by direct compression, were implanted subcutaneously and intramuscularly. On sequential time points, macroscopic observations of implantation sites were performed and tissue samples were removed, fixed, and histologically evaluated. No macroscopic inflammatory reaction was observed with Contramid.. Upon histologic examination, inflammatory reaction produced by Contramid was moderate and restricted to implantation sites. The sequence of inflammatory events with Contramid was similar regardless of implantation site. Degradation of Contramid pellets was characterized by fragmentation with formation of fibrovascular septa and phagocytosis by macrophages. Finally Contramid was mostly absorbed by the end of the 4-month period and substituted by adipocytes. It has been demonstrated that Contramid is a biocompatible and absorbable material.

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“…End-stage healing had occurred with the development of a fi brous capsule and similar histological response with this polymer was identifi ed at 3, 6, 9, and 12 months implantation [ 63 ] .…”

Section: Subcutaneous Implantation Studiesmentioning

confidence: 96%

Host Response to Long Acting Injections and Implants

Anderson

2011

Long Acting Injections and Implants

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Perspectives on the in vivo biocompatibility of drug delivery systems to be considered in the design, development, and evaluation of drug delivery systems are presented. Temporal events occurring in response to the implanted/injected drug delivery system are presented, including early events following injection/implantation, acute infl ammation, chronic infl ammation, granulation tissue formation, foreign body reaction, and fi brosis/fi brous encapsulation. Both nonbiodegradable and biodegradable/resorbable systems are discussed. Important in the identifi cation of biocompatibility of any drug delivery system is the intensity and/or time duration of the various components of the infl ammatory reaction, wound healing responses, and foreign body responses. Finally, a section on immunotoxicity (acquired immunity) has been included due to current events in development of controlled sustained release systems focused on delivery of biologically reactive agents that may potentially initiate an adaptive immune response. IntroductionIn the research and development of implantable or injectable long acting drug delivery systems, in vivo biocompatibility studies play an important role in determining the safety and effi cacy of these devices. The evaluation of the biocompatibility of implantable or injectable drug delivery systems requires an understanding of the infl ammatory and healing responses of implantable materials. For delivery systems, this includes an appreciation of the infl ammatory and healing responses of degradable/resorbable systems as well as nondegradable systems. In vivo biocompatibility

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Biotolerance of a semisolid hydrophobic biodegradable poly(ortho ester) for controlled drug delivery

Cited by 24 publications

References 12 publications

In situ gelation of PEG-PLGA-PEG triblock copolymer aqueous solutions and degradation thereof

In situ gelation of PEG-PLGA-PEG triblock copolymer aqueous solutions and degradation thereof

Tissue reaction and biodegradation of implanted cross‐linked high amylose starch in rats

Host Response to Long Acting Injections and Implants

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