Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Particulate form
Patent
1994-03-29
1997-06-03
Azpuru, Carlos
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Particulate form
424489, 424491, 424492, 424496, 424497, 424500, A61K 914, A61K 916, A61K 950
Patent
active
056352158
DESCRIPTION:
BRIEF SUMMARY
This invention concerns the subject of materials for embolization. In particular, it concerns new calibrated and adhesive particles, especially suited to embolization.
Therapeutic vascular occlusions (embolizations) are techniques used to treat certain pathological conditions in situ. They are practiced generally by means of catheters making it possible, under imagery control, to position particulate occlusion agents (emboli) in the circulatory system. They can concern the vessels of various processes: tumors, vascular malformations, hemorrhagic processes, etc. Notably, in the case of tumors, vascular occlusion can suppress pain, limit blood loss on the surgical intervention to follow embolization or even bring on tumoral necrosis and avoid the operation. In the case of vascular malformations, it enables the blood flow to the "normal" tissues to be normalized, aids in surgery and limits the risk of hemorrhage. In hemorrhagic processes, vascular occlusion produces a reduction of flow, which promotes cicatrization of the arterial opening(s).
Furthermore, depending on the pathological conditions treated, embolization can be carried out for temporary as well as permanent objectives.
Different types of emboli are known in the prior art. In particular, liquid agents (acrylic glues, gels, viscous suspensions, etc.) or particulate agents (miscellaneous polymers, dura mater, gelatin sponges, spheres, balloons, spirals, etc.) can be involved. The major disadvantages of the known liquid emboli reside in their toxicity to the tissues, which can generate necrosis phenomena, and in the risk sticking of the catheters.
The disadvantages of the solid emboli available are essentially due to their nonspherical and hard-to-calibrate shape, to their nonhydrophilic character, to their hardness or even to their very high cost.
The present invention makes it possible to remedy the above-mentioned disadvantages. The applicant has, in fact, uncovered particularly advantageous properties of certain spherical materials, making possible their very effective use as emboli, The invention also resides in new emboli obtained by modifications of those materials, with a view to their application in embolization.
One object of the invention resides more specifically in the use of microspheres comprising an hydrophilic acrylic copolymer coated with a cell adhesion promoter.
In particular, the invention concerns the use of microspheres of diameter ranging between about 10 to about 2,000 .mu.m.
Surprisingly, the microspheres defined above, present properties very advantageous for embolization. Notably, they are the only emboli combining properties of effectiveness, biocompatibility and stability.
More precisely, the microspheres used in the invention affords a 100% occlusion of the vascular lumen. Furthermore, they are easily calibrated, which makes possible a control of the distance of the occlusion. Finally, they are nonresorbable and nonbiodegradable, which allows for a durable occlusion.
On the other hand, these microspheres are nontoxic, biocompatible in vitro (with numerous cell lines) as well as in vivo and adhesive to the vascular wall through the cell growth they promote.
These microspheres are also stable. Thus, they are both flexible and deformable, in order to pass into small catheters without undergoing alteration, but perfectly resistant to the pressures generated by the embolization operations. They are likewise thermally stable, in order to be sterilized or frozen, and stable in suspension, in order to be preserved in suspension and injected with different liquids.
Finally, their hydrophilic character enables them to be placed in suspension, notably, in the form of sterile and pyrogenic injectable solutions, without formation of aggregates nor adhesion to the walls of the catheters, syringes, needles and other materials used in embolization.
The hydrophilic acrylic copolymer preferably comprises in copolymerized form about 25 to about 98% neutral hydrophilic acrylic monomar by weight, about 2 to about 50% difunctional monomer by
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Boschetti Egisto
Brouard Michel
Drouet Ludovic
Girot Pierre
Laurent Alexandre
Assistance Publique - Hopitaux de Paris
Azpuru Carlos
BioSepra S.A.
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