Injectable bio-active glass in a dextran suspension

Details Injectable bio-active glass in a dextran suspension Injectable bio-active glass in a dextran suspension

1998-11-23

2001-02-20

Azpuru, Carlos A. (Department: 1615)

Drug, bio-affecting and body treating compositions

Preparations characterized by special physical form

Implant or insert

C428S402000, C428S402240, C523S115000

Reexamination Certificate

active

06190684

ABSTRACT:

BACKGROUND OF THE INVENTION
It has been common practice in plastic, otolaryngological and other surgeries for many years to inject or place within tissues a variety of artificial substances to repair or reconfigure anatomic structures. For example, Teflon polytetrafluoroethylene) particles have been introduced into the vocal cords and more recently into periureteral and periurethral tissues with mixed results. Disadvantages associated with this procedure include long-term progressive foreign body reactions and migration and distant embolism associated with very small particles. Considerable research has been conducted to discover substitutes for Teflon and other conventionally employed artificial materials.
Bio-active glasses have been utilized as bone replacement materials in a variety of reconstructive surgical techniques. These glasses have been shown to develop a strong bond with hard tissue because of a series of ion exchange reactions between the implant surface and body fluids that result in the formation of a biologically active calcium phosphate film at the implant tissue interface. See Hench et al,
J. Biomed. Mater. Res.,
Vol. 5, pp. 117-141 (1971), and Hench et al,
J. Biomed. Mater. Res.,
Vol. 7, pp. 25-42 (1973). Bio-active glasses have also been shown to form firm bonds with soft tissue. See Wilson, et al,
J. Biomed. Mater. Res.,
Vol. 15, pp. 805-817 (1981); Wilson and Merwin,
J. Biomed. Mater. Res.: Applied Biomaterials,
Vol. 22, No. A2, pp. 159-177 (1988); and Wilson, Low et al,
Biomaterials and Clinical Applications,
Ed. by Pizzoferrato et al, Elsevier Science Publishers B. V., Amsterdam (1987).
Certain bio-active and bio-compatible glasses and glass-ceramics, e.g., those described in U.S. Pat. Nos. 4,159,358; 4,234,972; 4,103,002; 4,189,325; 4,171,544; 4,775,646; 4,851,046, and 5,074,916 (all incorporated herein by reference), have been shown to develop a unique, strongly adherent, chemical bond with hard tissue (bone) tissue due to the influence on hydroxyapatite of the biologically active calcium phosphate film generated in situ by ion-exchange reactions between the glass or glass-ceramic surface and body fluids. This influence results in a strong fixation of the glass or glass-ceramic to the bone surface. Although as noted above, a variety of such glasses have been shown to bond to various soft tissues, it has been found that several of these glasses result in the formation of an exceptionally thin (i.e., no more than about 1-3 fibers thick), but adherent collagen film which strongly adheres the glass to soft tissue without concomitant adverse side effects.
Failure to observe soft tissue bonding of some glasses was a consequence of inappropriate preparation of material and selection of inappropriate tissue sites, e.g., muscle. When the glass implant is successfully immobilized in appropriate soft tissue during the experimental period and when proper histological specimens are made, soft tissue adhesion to some glasses can be confirmed and evaluated. These particular glass compositions have also been found to advantageously become encapsulated with a thin (i.e., no more than about 1-3 fibers thick) layer of collagen after implantation.
SUMMARY OF THE INVENTION
The present invention is directed to pharmaceutically acceptable fluid compositions particularly adapted for injection via a surgical needle into an animal, and methods of treatment using the compositions. The compositions include a suspension of a bio-active and bio-compatible glass particulate composition and dextrans or dextran derivatives having an average molecular weight of about 10,000 to about 2×10
6
.
DETAILED DESCRIPTION OF THE INVENTION
The term “fluid” as used herein means any flowable and injectable liquid composition, including highly viscous compositions sometimes referred to as “pastes.”
As used herein, the term “animal” means mammal, including a human. Unless specified otherwise the term “patient” means a human patient.
The term “pharmaceutically acceptable” as used herein is consistent with the art and means compatible with the other ingredients of a pharmaceutical composition and not deleterious to the recipient thereof.
The term “surgical needle” means any needle adapted for delivery of the fluid compositions of the present invention into a selected anatomical structure including a barrel type injector without a needle.
The term “anatomic structure” refers to any site or locus composed of hard tissue (bone) and/or soft tissue within the body of an animal.
The term “anatomic integrity” refers to the desired size, shape or configuration of a particular anatomic structure after bonding therewith of the particulate glass phase of the composition of the present invention.
The term “homogenous” as used herein is intended to include all compositions not subject to preferential extrusion of one or more of the components when injected into an animal.
Anatomic structures treatable according to the method of the present invention include, but are not limited to, vocal cords, periurethral tissue, periureteral tissue, maxilla, mandible, temporomandibular joint, chin, zygomatic arch, nose, ear, tooth root canal, tooth pulp caps, dental restoration, defects in bone, vertebral spaces, articulating joints, urethra, and subcutaneous and intradermal soft tissues. In addition, the compositions of the present invention are useful in treating:
Geneto-urinary indications including vesico-uretal (Renal) reflux, stress incontinence, post-prostatectomy stress incontinence, intrinsic sphincter deficiency, efferent limb incompetence, etc.
Gastro-enterological indications including gastro-esophageal reflux, gastric banding, fecal incontinence, etc.
Otolaryngologic indications including unilateral vocal cord paralysis, velopharyngeal incompetence, adductor laryngeal dystonia (spastic dysphonia), glottic insufficiency, etc.
Dermatologic indications including cutaneous contour deficiencies, wrinkle correction (e.g., glabellar furrows, nasolabial lines), depressed scars (due to e.g., acne, trauma, prior surgery, steroid- or disease induced areas of atrophy, post-rhinoplasty irregularities, depressed skin grafts), etc.
Vascular indications including sclerotherapy for peripheral vascular disorders, etc.
As noted above in the discussion of the background of this invention, bio-active and bio-compatible material, especially ceramic and glass material, are known in the art of medicine as useful in the restoration of bone and soft tissue. This art is discussed extensively in
Introduction to Bioceramics,
Ed., L. L. Hench and J. Wilson, especially chapter 1, World Scientific, London (19**). The bio-active glass materials for use in the compositions and methods described herein can be selected on the basis that they:
(a) form strong adherent bonds comprising a thin layer of collagen at a glass/soft tissue interface upon injection in the animal;
(b) form strong adherent bonds comprising a layer of collagen no more than about 1-3 fibers thick;
(c) become encapsulated after injection in the animal with a collagen layer attached by chemical and mechanical bonding to the bio-active surface;
(d) do not after injection into the animal contribute to the formation of excess scar tissue, giant cells or acute inflammatory cells; and do not cause long lasting foreign body reactions.
Bioactive glasses are any glass capable of forming hydroxyapatite after exposure to simulated body fluid. For example, bio-active and bio-compatible glasses having the following weight percent compositions give satisfactory results when utilized as the particulate glass.
Component
Mole Percentage
SiO
2
40-86
CaO
15-46
Na
2
O
 0-35
P
2
O
5
1-8
CaF
2
 0-25
B
2
O
3
 0-10
The bio-active particulate glass used in the present invention may be prepared according to the methods of the art such as taught in U.S. Pat. Nos. 4,159,358; 4,234,972; 4,103,002; 4,189,325; 4,171,544; 4,775,646; 4,851,046, and 5,074,916. For example, the raw materials (e.g., SiO
2
, CaO, Na
2
O and P
2
O
5
) are mixed in a Nalgene (trademark) plastic contain

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