title: Intraocular degradation behavior of crosslinked and linear poly(trimethylene carbonate) and poly(D,L-lactic acid).
abstract: The intraocular degradation behavior of poly(trimethylene carbonate) (PTMC) networks and poly(D,L-lactic acid) (PDLLA) networks and of linear high molecular weight PTMC and PDLLA was evaluated. PTMC is known to degrade by enzymatic surface erosion in vivo, whereas PDLLA degrades by hydrolytic bulk degradation. Rod shaped specimens were implanted in the vitreous of New Zealand white rabbits for 6 or 13 wk. All materials were well tolerated in the rabbit vitreous. The degradation of linear high molecular weight PTMC and PTMC networks was very slow and no significant mass loss was observed within 13 wk. Only some minor signs of macrophage mediated erosion were found. The fact that no significant enzymatic surface erosion occurs can be related to the avascularity of the vitreous and the limited number of cells it contains. PDLLA samples showed more evident signs of degradation. For linear PDLLA significant swelling and a large decrease in molecular weight in time was observed and PDLLA network implants started to lose mass within 13 wk. Of the tested materials, PDLLA networks seem to be most promising for long term degradation controlled intravitreal drug delivery since this material degrades without significant swelling. Furthermore the preparation method of these networks allows easy and efficient incorporation of drugs.
authors.affiliation: MIRA Institute for Biomedical Technology and Technical Medicine and Department of Biomaterials Science and Technology, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE, Enschede, The Netherlands.
authors.forename: Janine
authors.initials: J
authors.lastname: Jansen
authors.forename: Steven A
authors.initials: SA
authors.lastname: Koopmans
authors.forename: Leonoor I
authors.initials: LI
authors.lastname: Los
authors.forename: Roelofje J
authors.initials: RJ
authors.lastname: van der Worp
authors.forename: Johanna G
authors.initials: JG
authors.lastname: Podt
authors.forename: Johanna M M
authors.initials: JM
authors.lastname: Hooymans
authors.forename: Jan
authors.initials: J
authors.lastname: Feijen
authors.forename: Dirk W
authors.initials: DW
authors.lastname: Grijpma
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism*; D004146:Dioxanes / Q000737:chemistry / Q000378:metabolism*; D016503:Drug Delivery Systems; D005260:Female; D020007:Implants, Experimental; D056965:Injections, Intraocular; D019344:Lactic Acid / Q000737:chemistry / Q000378:metabolism*; D008422:Materials Testing; D015394:Molecular Structure; D008970:Molecular Weight; D011091:Polyesters; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*; D011817:Rabbits; D014822:Vitreous Body / Q000737:chemistry / Q000378:metabolism*
chemical_list: D001672:Biocompatible Materials; D004146:Dioxanes; D011091:Polyesters; D011108:Polymers; C059299:polytrimethylene carbonate; D019344:Lactic Acid; C033616:poly(lactide)