Biomedical subjects

J Vandorpe

Publications and source records attributed to J Vandorpe.

3 recordsLinked to original sources

PubMed1997

Long circulating biodegradable poly(phosphazene) nanoparticles surface modified with poly(phosphazene)-poly(ethylene oxide) copolymer.

The biodistribution of biodegradable poly(organo phosphazene) nanoparticles surface modified by adsorption of a novel poly(organo phosphazene)-poly(ethylene oxide) copolymer with a 5000 M(W) PEO chain (PF-PEO[5000]), following intravenous administration in rats and rabbits, is described. The data are compared to the biodistribution of poly(organo phosphazene) and poly(lactide-co-glycolide) nanoparticles coated with a tetrafunctional copolymer of poly(ethylene oxide)-poly(propylene oxide) ethylenediamine, commercially available as Poloxamine 908. This copolymer has a PEO chain of the same size as the poly(organo phosphazene)-PEO derivative used. The results in the rat model reveal that poly(organo phosphazene) nanoparticles with a Poloxamine 908 coating were mainly captured by the liver, although a retardation in clearance from the systemic circulation was seen. In contrast, the poly(organo phosphazene) nanoparticles coated with PF-PEO(5000) showed a prolonged blood circulating profile, with only a small amount of the nanoparticles sequestered by the liver. This indicates the importance of the nature of both the anchoring group and the particle surface on the biological performances of the system. Study of the biodistribution of the PF-PEO(5000)-coated poly(organo phosphazene) nanoparticles in the rabbit model also indicated a prolonged systemic circulation lifetime and reduced liver uptake, whereby a significant amount of the administered nanoparticles was targeted to the bone marrow.

Animals↗

PubMed1995

Biocompatibility of polymer-coated oversized metallic stents implanted in normal porcine coronary arteries.

Polymer coatings have been suggested to decrease the thrombogenicity of metallic intravascular stents. The purpose of the present study was to investigate the intimal response to two different polymers when used as coatings for stents implanted in normal porcine coronary arteries. Non-articulated stainless steel-slotted tube stents were coated with either a biodegradable poly(organo)phosphazene with amino-acid ester side groups or a biostable polyurethane prepared from an amphiphilic polyether, dephenylmethane-4,4'-diisocyanate and butane diol as chain extender. In order to induce vascular wall injury, the stents were deployed using an oversized balloon. At 6 weeks follow-up, the angiographic luminal diameter measured in four polyurethane-coated stents and in six bare metallic stents was similar and 20% less than immediately post-stenting. However, in four polyphosphazene-coated stents the difference was 65% (P = 0.01 when compared to bare metal). At post-mortem morphometry the degree of luminal area stenosis was also similar in polyurethane-coated and in bare metallic stents (32 +/- 7.6% vs. 39 +/- 14%, NS) but reached 81 +/- 19% in polyphosphazene-coated stents (P < 0.03 when compared to bare metal). Thus, poly(organo)phosphazene induced a more pronounced histiolymphocytic and fibromuscular reaction than amphiphilic polyurethane, which appeared to be promising as biocompatible stent coating and, consequently, as a potential carrier for vasoactive drugs.

Animals↗

PubMedDate not supplied

Biocompatibility of biodegradable and nonbiodegradable polymer-coated stents implanted in porcine peripheral arteries.

PURPOSE: To investigate the neointimal response to poly(organo)phosphazene- and amphiphilic polyurethane-coated, oversized, stainless steel stents implanted in porcine peripheral arteries. METHODS: Nonarticulated, stainless steel, slotted-tube stents were coated with 1) a biodegradable poly-(organo)phosphazene with aminoacid ester side groups and 2) a biostable polyurethane prepared from an amphiphilic polyether, diphenyl methane-4,4'-diisocyanate and butane diol as chain extender. The stents were deployed in porcine peripheral arteries using an oversized balloon. RESULTS: The neonintimal response to amphiphilic polyurethane-coated stents was similar to the uncoated metallic stents. Poly(organo)phosphazene-coated stents, however, induced a severe histiolymphocytic and fibromuscular reaction resembling a foreign body reaction. CONCLUSIONS: Amphiphilic polyurethane is very promising as a biocompatible stent coating. Poly-(organo)phosphazene, however, appears unsuitable for this purpose.

Angioplasty, Balloon↗