Producing stable cross-linked alginate gel by binding...

Details Producing stable cross-linked alginate gel by binding... Producing stable cross-linked alginate gel by binding...

2000-01-27

2003-07-15

Naff, David M. (Department: 1651)

Drug, bio-affecting and body treating compositions

Preparations characterized by special physical form

Implant or insert

C424S093700, C424S490000, C424S491000, C435S178000, C435S382000

Reexamination Certificate

active

06592886

ABSTRACT:

BACKGROUND OF THE INVENTION
The subject of the invention is the production of polymer alginate material, especially the production of alginate beads or films, the use of such alginate materials and biological implants that are enclosed in or coated with such alginate materials.
It is known that, with allogene or xenogene transplantations, immune responses of the host organism can be countered by microencapsulation of the transplant for the purpose of immunoisolating it (see F. Lim et al. in “Science”, vol. 210, 1980, pp 908-910, H. A. Clayton et al. in “Acta Diabetol.”, vol. 30, 1993, pp 181-189). Spherical alginate beads have proven their advantages in encapsulating allogene or xenogene, endocrine tissue (for example see T. Zekorn et al. in “Acta Diabetol.”, vol. 29, 1992, pp 41-52, P. De Vos et al. in “Biomaterials”, vol. 18, 1997, pp 273-278, C. Hasse et al. in “Exp. Clin. Endocrinol. Diabetes”, vol. 105, 1997, pp 53-56, and in “J. Microencapsulation”, vol. 14, 1997, pp 617-626). The alginates are Ca
2+
or Ba
2+
linked and especially effective in immuno-isolation if they are purified, ie as free as possible of mitogeneous contamination (see U. Zimmermann et al. in “Electrophoresis”, vol. 13, 1992, pp 269-274, G. Klöck et al. in “Biomaterials”, vol. 18, 1997, pp 707-713).
The transplantation of alginate encapsulated tissue is not only tested in animal experiments but is already being introduced in human medicine. Thus C. Hasse et al. in “The Lancet”, vol. 350, 1997, p 1296, for example, describe microencapsulation in the case of an allogene parathyroid transplantation in the muscle tissue of two patients with permanent symptomatic hypoactivity of the parathyroid. After treatment with alginate immuno-isolated parathyroid tissue, it was possible for the patients to leave hospital without showing hypocalcaemic symptoms and without requiring therapy to suppress immune responses. Nevertheless, as before in animal experiments, the transplants were only effective for a limited time, which can be traced to the disappearance of the alginate enclosure.
From U.S. Pat. No. 5,429,821 we know of the formation of alginate coated transplants where, to increase alginate stability, Ca
2+
linked alginate gel is cross-linked with L-poly-lysine or other physiologically acceptable, non-toxic polycations. The advantage of this technique is improved alginate stability. But cross-linking with L-poly-lysine is nevertheless a disadvantage, because the embedded transplant can trigger fibrosis, resulting in problems as in the use of unpurified alginates. Consequently, further treatment of the alginate gels is necessary to achieve biocompatibility of the transplant.
The stability of the transplanted alginate beads is a general problem that is also described by G. Klöck et al. in “Biomaterials”, vol. 18, 1997, pp 707-713, for example, and by P. De Vos in “Diabetologia”, vol. 40, 1997, pp 262-270. Continuing clinical use of alginate encapsulated transplants calls for the development of more stable alginate beads.
SUMMARY OF THE INVENTION
The object of the invention is to propose a method for producing alginate material, especially for enclosing or coating transplants, that results in enhanced stability and reliability of the alginate material in practical conditions. It is also the object of the invention to propose new uses for such alginate material and new transplants provided with improved alginate material of this kind.
These objects are resolved by a method with the features of patent claim
1
. Advantageous embodiments of the invention result from the attached claims.


REFERENCES:
patent: 4409331 (1983-10-01), Lim
patent: 4781676 (1988-11-01), Schweighardt et al.
patent: 5429821 (1995-07-01), Dorian et al.
patent: 5718862 (1998-02-01), Thompson
patent: 6365385 (2002-04-01), Opara
patent: 6375985 (2002-04-01), Bomberger et al.
patent: 44 26 396 (1996-02-01), None
patent: 187 07 910 (1998-09-01), None
F.Lim et al. in “Science”, vol. 210, Nov. 1980, p. 908-910; “Microencapsulated Islets as Bioartificial Endocrine Pancreas”.
H.A. Clayton et al., in “Acta Diabetol.”, vol. 30, 1993, p. 181-189; “Islet microencapsulation: a review”.
T.Zekorn et al. in “Acta Diabetol.”, vol. 29, 1992, p.99-106; “Barium-cross-linked alginate beads: a simple, one-step method for successful immunoisolated transplantation of islets of Langerhans”.
P. DeVos et al. in “Biomaterials”, vol. 18, 1997, p. 1085-1090; “Upscaling the production of microencapsulated pancreatic islets”.
C.Hasse et al. in “Exp. Clin. Endocrinol. Diabetes”, vol. 105, 1997, p.53-56; “Isotransplantation of microencapsulated parathyroid tissue in rats”.
“J. Microencapsulation”, vol. 14, No. 5, 1997, p. 617-626; “First successful xenotransplantation of microencapsulated human parathyroid tissue in experimental hypoparathyroidism: long-term function without immunosuppression”.
U.Zimmerman et al. in “Electrophoresis”, vol. 13, 1992, p. 269-274; “Production of mitogen-contamination free alginates with variable ratios of mannuronic acid to guluronic acid by free flow electrophoresis”.
G.Klock et al. in “Biomaterials”, vol. 18, 1997, p. 707-713; “Biocompatibility of mannuronic acid-rich alginates”.
C.Hasse et al. in “The Lancet”, vol. 350, 1997, p. 1296; “Parathyroid allotransplantation without immunosuppression”.
P. de Voss et al. in “Diabetologia”, vol. 40, 1997, p. 262-270; “Improved biocompatibility but limited graft survival after purification of alginate for microencapsulation of pancreatic islets”.
P. Grohn et al. in “Exp. Clin. Endocrinol.”, vol. 102, 1994, p. 380-387; “Large-scale production of Ba2+-alginate-coated islets of Langerhans for immunoisolation”.
P. Grohn et al. “BioTechniques”, vol. 22, May 1997, p. 970-975; “Collagen-Coated Ba2+-Alginate Microcarriers for the Culture of Anchorage-Dependent Mammalian Cells”.

Affiliated with

Also associated with

Rating

Producing stable cross-linked alginate gel by binding... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Producing stable cross-linked alginate gel by binding..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Producing stable cross-linked alginate gel by binding... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3046316