Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Particulate form
Reexamination Certificate
2001-03-13
2003-11-25
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Particulate form
C424S499000, C424S501000, C424S009100, C424S422000, C424S423000, C424S424000, C424S425000, C424S426000, C424S484000, C424S486000, C514S772000, C514S772100, C514S772200
Reexamination Certificate
active
06652883
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to compositions for use in tissue bulking and coating. More specifically, the invention relates to compositions including crosslinkable macromonomers (also referred to herein as macromers) that form hydrogels useful in tissue bulking and coating. The invention also relates to methods for tissue bulking and coating.
There are many instances in which an appropriate biomaterial is needed for use in repair of tissues and in augmentation of tissues. Applications for an appropriate biomaterial include repair of defects and conditions in a tissue caused by disease, injury, or aging, repair of congenital defects and conditions in a tissue, and augmentation of tissues to provide a desirable functional, reconstructive, or cosmetic change. Biomaterials are also needed for sealing tissues to prevent post operation leakage, for tissue adherence, and for prevention of tissue adhesion. Biomaterials are also needed for cell encapsulation for forming bioreactors, for example, and for cell implantation.
Gastroesophageal reflux is a physical condition in which stomach acids reflux, or flow back from the stomach into the esophagus. Frequent reflux episodes (two or more times per week), may result in a more severe problem known as gastroesophageal reflux disease (GERD). The primary cause of GERD is believed to be the lack of competency of the lower esophageal sphincter. The lower esophageal sphincter, or valve, is comprised of smooth muscle located at the gastroesophageal (GE) junction and functions to allow food and liquid to pass into the stomach but prevent regurgitation of stomach contents. Bulking of the lower esophageal sphincter may be beneficial.
Vesicoureteral reflux is a condition wherein there is an abnormal development of the ureteral bud as it enters the bladder during embryologic development. The shortened course of the ureter through the bladder musculature decreases the ureteral resistance and allows for urine to reflux from the bladder reservoir back up into the ureter and into the kidney. Vesicoureteral reflux can be treated by endoscopic injection of a bulking agent in the submucosal space. Generally, a cystoscope is inserted into the bladder, a needle is inserted through the cystoscope and placed under direct vision underneath the refluxing ureter in the submucosal space, and the bulking agent is injected until the gaping ureteric orifice configuration changes into a half-moon slit.
Urinary incontinence is the inability to retain urine and not void urine involuntarily. As a person ages, his ability to voluntarily control the sphincter muscle is lost in the same way that general muscle tone deteriorates with age. This can also occur when a radical event such as paraplegia “disconnects” the parasympathetic nervous system causing a loss of sphincter control. Some types of incontinence can be treated by injection of a bulking agent into the submucosa of the urethra, in order to “beef up” the area and improve muscle tone.
Biomaterials are used in a number of applications in the field of plastic and reconstructive surgery. For example, various compositions have been used for implantation in the lips and to fill in wrinkles. Biomaterials have also been used as breast implants, typically encased within a silicone shell.
Biomaterials have been used in repair of hard tissue such as cartilage and bone. Musculoskeletal damage can occur due to injury or decay and can be repaired, in some cases, by replacement of the damaged tissue with an appropriate biomaterial.
In many tissue repair and augmentation applications, the ideal biomaterial should be easy to inject, well tolerated, not reabsorbed, and not prone to migration. In some cases, it may be desirable for the biomaterial to degrade and be absorbed over a period of time. In some applications, it may be desirable to form the implant ex vivo. In such cases, the biomaterial need not be injectable.
SUMMARY OF THE INVENTION
The invention relates to compositions for use in tissue bulking and coating. More specifically, the invention relates to compositions including crosslinkable macromonomers (also referred to herein as macromers) that form hydrogels useful in tissue bulking and coating. The invention also relates to methods for tissue bulking and coating.
The compositions include macromers having a backbone of a polymer having units with a 1,2-diol and/or 1,3-diol structure. Such polymers include poly(vinyl alcohol) (PVA) and hydrolyzed copolymers of vinyl acetate, for example, copolymers with vinyl chloride, N-vinylpyrrolidone, etc. The backbone polymer contains pendant chains bearing crosslinkable groups and, optionally, other modifiers. When crosslinked, the macromers form hydrogels having many properties advantageous for use as agents to bulk and coat tissues.
The compositions can be used for a variety of applications such as, but not limited to, bulking of the lower esophageal sphincter to treat GERD, urethral bulking to treat urinary incontinence, bulking of the ureteral to treat vesicoureteral reflux, esophageal bulking, tissue reconstruction due to injury or disease (i.e. reconstruction of a breast after partial mastectomy), tissue augmentation, and spinal disc replacement.
In one embodiment, the composition forms a permanent mass. In another embodiment, the composition forms a temporary or reversible (the terms temporary and reversible are herein used interchangeably) mass. Temporary bulking may be desired, for example, when using the composition in combination with cells to encourage cell regrowth. The composition can be designed to degrade as the cells develop into tissue. Temporary bulking can be achieved by using a fully or partially degradable composition or a composition that degrades in response to an applied condition, such as a change in temperature or pH.
The processes for using the compositions include dissolving the macromers in solution and delivering the solution to the intended site of bulking, using a delivery device such as a catheter or syringe. The macromers form a crosslinked hydrogel. In one embodiment, the macromers are exposed to the crosslinking initiator before they are administered to the intended site of bulking. In one embodiment, the macromers are formed into the crosslinked hydrogel prior to implantation.
DETAILED DESCRIPTION OF THE INVENTION
The invention relates to compositions for use in tissue bulking and coating. More specifically, the invention relates to compositions including crosslinkable macromonomers (also referred to herein as macromers) that form hydrogels useful in tissue bulking and coating. The invention also relates to methods for tissue bulking and coating.
The term “bulking” as used herein refers to partially or fully bulking a tissue or partially or fully filling a biological cavity. The cavity can be preexisting or formed for the purpose. Bulking can be performed, for example, for reconstruction, augmentation, or replacement of body tissue. Examples of bulking include bulking of the lower esophageal sphincter to treat GERD, urethral bulking to treat urinary incontinence, bulking of the ureteral bud to treat vesicoureteral reflux, esophageal bulking, tissue reconstruction due to injury or disease (i.e. reconstruction of a breast after partial mastectomy), tissue augmentation, and spinal disc replacement.
The term “sealing” as used herein refers to partially or fully covering a tissue or cell with the biomaterial. Sealing can be performed, for example, for adhesion prevention, to promote adhesion between surfaces, or for tissue or cellular encapsulation.
The compositions include macromers having a backbone of a polymer comprising units with a 1,2-diol and/or 1,3-diol structure and having at least two pendant chains including a crosslinkable group and optionally other pendant chains containing modifiers. The macromers form a hydrogel when crosslinked.
The compositions can be produced very simply and efficiently due to a number of factors. Firstly, the starting materials, such as the polymer backbones, are inexpensive to obtain or prepa
Asfaw Bruktawit T.
Chaouk Hassan
Goodrich Stephen D.
Goupil Dennis W.
Holland Troy
Beard Collen A.
BioCure, Inc.
Di Nola-Baron Liliana
Page Thurman K.
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