U.S. patent number RE32,969 [Application Number 07/116,579] was granted by the patent office on 1989-06-27 for injectionable visoelastic ophthalmic gel.
Invention is credited to Victoria S. Chylinski, Seymour F. Trager.
United States Patent |
RE32,969 |
Trager , et al. |
June 27, 1989 |
**Please see images for:
( Certificate of Correction ) ** |
Injectionable visoelastic ophthalmic gel
Abstract
An improved injectionable viscoelastic gel for use in opthalmic
surgical and treatment procedures, wherein the gelling agent is a
high molecular weight polyacrylamide or polymethacrylamide.
Inventors: |
Trager; Seymour F. (Plainview,
NY), Chylinski; Victoria S. (Stroud, Glos., GB2) |
Family
ID: |
27381848 |
Appl.
No.: |
07/116,579 |
Filed: |
August 24, 1987 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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434412 |
Oct 14, 1982 |
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Reissue of: |
625249 |
Jun 27, 1984 |
04540568 |
Sep 10, 1985 |
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Current U.S.
Class: |
424/78.04;
514/912 |
Current CPC
Class: |
A61K
31/785 (20130101); A61F 2/14 (20130101); A61L
27/52 (20130101); A61L 27/16 (20130101); A61K
9/0048 (20130101); A61L 27/16 (20130101); A61L
27/52 (20130101); A61F 2/14 (20130101); C08L
33/26 (20130101); A61K 31/74 (20130101); C08L
33/26 (20130101); A61L 27/16 (20130101); C08L
33/26 (20130101); A61L 2400/06 (20130101) |
Current International
Class: |
A61L
27/00 (20060101); A61L 27/16 (20060101); A61L
27/52 (20060101); A61K 31/785 (20060101); A61K
31/74 (20060101); A61K 9/00 (20060101); A61K
031/78 () |
Field of
Search: |
;424/81 ;514/912 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Chem. Abst., 76:90018(h) (1972)-Leong et al. .
Chem. Abst. 76:90019(j) (1972)-Lemp et al..
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Primary Examiner: Robinson; Douglas W.
Assistant Examiner: Fay; Zahrey
Attorney, Agent or Firm: Fidelman & Wolffe
Parent Case Text
.Iadd.This is a continuation-in-part of Ser. No. 434,412, filed
Oct. 14, 1982, now abandoned. .Iaddend.
Claims
What is claimed is:
1. An injectionable viscoelastic gel particularly adapted for use
in ophthalmic surgical procedures and treatments .[.which.]..Iadd.,
said .Iaddend.gel consisting essentially of from about 2 to about 5
percent by weight of a polymer selected from polyacrylamide and
polymethacrylamide, said polymer having a molecular weight of from
about 1 to about 6 million.[.;.]..Iadd., .Iaddend.from about 0.4 to
about 8.6 percent by weight sodium chloride, from about 0.075 to
about 0.3 percent by weight .[.postassium.]. .Iadd.potassium
.Iaddend.chloride, from about 0.04 to about 0.33 percent by weight
calcium chloride, from about 0.02 to about 0.04 percent by weight
magnesium chloride hexahydrate, from about 0.3 to about 0.4 percent
by weight sodium acetate, from about 0.15 to about 0.20 percent by
weight of a buffer, remainder water.
2. A gel as defined in claim 1 wherein said polymer is
polyacrylamide.
3. A gel as defined in claim 1 wherein said polymer is present in
an amount of from about 3.5 to about 4.5 percent by weight.
4. A gel as defined in claim 1 wherein said polymer has a molecular
weight of from about 4.5 to about 5.5 million.
5. A gel as defined in claim 1 wherein said buffer is sodium
citrate dihydrate.
6. A gel as defined in claim 1 consisting essentially of about 4
percent by weight of said polymer having a molecular weight of
about 5 million, about 0.049 percent by weight sodium chloride,
about 0.075 percent by weight potassium chloride, about 0.048
percent by weight calcium chloride, about 0.03 percent by weight
magnesium chloride hexahydrate, about 0.17 percent by weight sodium
citrate dihydrate, remainder water. .Iadd.
7. A method for protecting ocular tissue during ophthalmic surgery
which comprises
injecting into an ocular chamber prior to said surgery an amount of
viscoelastic gel sufficient to prevent mechanical damage and
denudation of said ocular tissue during said surgery, said
viscoelastic gel comprising a polymer selected from polyacrylamide,
polymethacrylamide and a copolymer of acrylamide and
methacrylamide, said polymer having a molecular weight of from
about 1 to 6 million, and a pharmaceutically acceptable diluent
therefor. .Iaddend. .Iadd.8. The method of claim 7 wherein said
surgical procedure is an anterior segment surgical procedure.
.Iaddend. .Iadd.9. The method of claim 8 wherein said anterior
segment surgical procedure is cataract removal, corneal transplant,
keratoplasty or bullous
rhegmatogenous retinal detachment. .Iaddend. .Iadd.10. The method
of claim 7 wherein said polymer is present in an amount between
about 2 to about 5 percent by weight of said viscoelastic gel.
.Iaddend. .Iadd.11. The method of claim 7 wherein said polymer is
present in an amount between about 3.5 to about 4.5 percent by
weight of said viscoelastic gel. .Iaddend. .Iadd.12. The method of
claim 7 wherein said polymer is present in an amount between about
4.5 to about 5.5 percent by weight of said viscoelastic gel.
.Iaddend. .Iadd.13. The method of claim 7 wherein said polymer is
present in an amount between about 4 percent by weight of said
viscoelastic gel. .Iaddend. .Iadd.14. The method of claim 7 wherein
said polymer is polyacrylamide. .Iaddend. .Iadd.15. The method of
claim 7 wherein said viscoelastic gel comprises
(a) 2 to 5 percent by weight of said polymer;
(b) 0.4 to 8.6 percent by weight sodium chloride;
(c) 0.075 to 0.3 percent by weight potassium chloride;
(d) 0.04 to 0.33 percent by weight calcium chloride;
(e) 0.02 to 0.04 percent by weight magnesium chloride
hexahydrate;
(f) 0.3 to 0.4 percent by weight sodium acetate;
(g) 0.15 to 0.20 percent by weight buffering agent; and
(h) remainder water. .Iaddend. .Iadd.16. The method of claim 15,
wherein said buffering agent is sodium citrate dihydrate. .Iaddend.
.Iadd.17. The method of claim 7 wherein said viscoelastic gel
consists essentially of about 4 percent by weight of said polymer
having a molecular weight of about 5 million, about 0.49 percent by
weight sodium chloride, about 0.075 percent by weight potassium
chloride, about 0.048 percent by weight calcium, about 0.03 percent
by weight magnesium chloride hexahydrate, about 0.17 percent by
weight sodium citrate dihydrate, remainder water. .Iaddend.
Description
BACKGROUND OF THE INVENTION
This invention relates to ophthalmic surgery and treatment. More
particularly, this invention relates to a composition particularly
suitable for use as an adjunct in ophthalmic surgery.
In surgical procedures involving ocular tissue such as, for
example, anterior segment surgery, it is always necessary to
protect the corneal endothelium from mechanical damage. Failure to
provide adequate protection can result in irreparable damage to the
tissue.
Presently, ophthalmic surgical procedures are carried out in a
viscoelastic medium so as to prevent mechanical damage and
denudation of the tissue surfaces. Sodium hyaluronate is currently
widely used as the viscoelastic substance, presenting both positive
and negative facets in ophthalmic surgical procedures. Positively,
the hyaluronate has been reported as protecting the corneal
endothelium; however, great care must be exercised in the use of
hyaluronate, and in many instances, undesirable post-operative
pressure increases have been noted, with dilation and, in some
instance, adhesion development between the posterior capsule and
the iris.
It is an object of the present invention to provide an improved
injectionable ocular surgical and treatment adjunct.
It is a further object of the present invention to provide an
improved injectionable viscoelastic solution which is nonreactive
with ocular tissues.
A further object of the present invention is to provide an improved
injectionable viscoelastic solution which may be employed without
postoperative complications in such anterior segment surgical
procedures as cataract removal, corneal transplants, penetrating
keratoplasty, correctional treatment of bullous rhegmatogenous
retinal detachment and the like.
These and other objects will become apparent from the disclosure
which follows.
STATEMENT OF THE INVENTION
In accordance with the present invention, there is provided an
improved viscoelastic gel comprising:
an acrylamide polymer selected from polyacrylamide and
polymethacrylamide
sodium chloride
potassium chloride
calcium chloride
magnesium chloride hexahydrate
sodium acetate
buffer
water
In this particularly effective formulation, it has been found that
the effectiveness thereof is achieved by compounding the
constituents thereof within certain, well-defined ranges and by
employing polyacrylamides and polymethacrylamides of certain,
well-defined molecular weights.
The polyacrylamides found to be effective in the present
compositions are polymers having a molecular weight of from about 1
to 6 million, produced by the polymerization of acrylamide,
methacrylamide, or mixtures thereof by methods known to the art.
Preferably, the polymers have a molecular weight on the order of
about 5 million. Inclusion of the polymer in the gel formulation is
maintained within from about 2 to about 5 percent by weights,
preferably from about 3.5 to about 4.5 percent by weight, and most
preferably about 4.0 percent by weight.
The remaining constituents of the formulation are present in the
following amounts, based upon percent by weight:
______________________________________ sodium chloride 0.4-8.6
potassium chloride 0.075-0.3 calcium chloride 0.04-0.33 magnesium
chloride 0.02-0.04 hexahydrate sodium acetate 0.3-0.4 buffer
0.15-0.20 water remainder
______________________________________
A particularly suitable formulation is a 4.0 percent by weight
polymer gel containing 0.49 percent by weight sodium chloride,
0.075 percent by weight potassium chloride, 0.048 percent by weight
calcium chloride, 0.03 magnesium chloride hexahydrate and 0.17
sodium citrate dihydrate as the buffering agent.
While sodium citrate dihydrate is preferred as a gel buffer, other
pharmaceutically acceptable buffering agents such as sodium
phosphates and sodium borates may be advantageously employed.
The composition is formulated by autoclaving at sterilization
temperatures an 8-10 percent by weight of the polymer and admixing
the sterile gel with the premixed salt solution. It has been found
that compounding of the polymer with the salt constituents prior to
sterilization results in a rise in pH above an acceptable
level.
The viscoelastic gels of the present invention are, as previously
stated, particularly useful in ocular surgical procedures as a
surgical adjunct, exhibiting:
(a) protective properties for corneal endothelium, iris and retinal
tissue;
(b) superior properties as an aqueous humor replacement;
(c) ability to maintain a deep anterior chamber during operative
procedures;
(d) ability to separate effectively tissue surfaces and thereby
minimize adhesion; and
(e) biocompatibility with intra ocular tissues.
The particular effectiveness of this specific formulation as an
adjunct in ophthalmic surgery is a direct result of its balanced
viscoelastic properties. The viscous nature thereof provides
mechanical protection for tissues (iris, retina) and cell layers
(corneal endo- and epithelium) which may be exposed to mechanical
damage during surgery. Further, due to the physical properties of
the formulation, the gel does not flow out of the anterior chamber,
providing a deep anterior chamber during surgical
manipulations.
The following example serves to illustrate the present
invention.
EXAMPLE 1
An autoclaved polyacrylamide having a molecular weight of about 5
million was admixed with a premixed salt solution to yield the
following homogenous gel composition:
______________________________________ Component Percent by Weight
______________________________________ polyacrylamide 4.0 sodium
chloride 0.049 potassium chloride 0.075 calcium chloride 0.048
magnesium chloride 0.030 hexahydrate sodium acetate 0.390 sodium
citrate dihydrate 0.170 water remainder
______________________________________
The gel, when utilized in standard testing for biocompatibility and
irritation determinations, produced no adverse reactions in the
ocular tissues of the test animals.
EXAMPLE 2
An autoclaved polymethacrylate having a molecular weight of about 5
million was admixed with a premixed salt solution to yield the
following homogenous gel composition:
______________________________________ Component Percent by Weight
______________________________________ polymethacrylamide 4.0
sodium chloride 0.049 potassium chloride 0.075 calcium chloride
0.048 magnesium chloride 0.030 hexahydrate sodium acetate 0.390
sodium citrate dihydrate 0.170 water remainder
______________________________________
The gel, when utilized in standard testing for biocompatibility and
irritation determinations, produced no adverse reactions in the
ocular tissues of the test animals.
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