Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Particulate form
Reexamination Certificate
2000-02-15
2002-09-10
Dees, Jose′ G. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Particulate form
Reexamination Certificate
active
06447805
ABSTRACT:
The present invention is concerned with a composition suitable for implantation at or in the vicinity of a body orifice or sphincter muscle to aid correct function.
Many body unctions rely upon the correct functioning of sphincter muscles. For example, the pyloric sphincter controls when the contents of the stomach pass into the small intestine. Similarly, the urethral sphincter controls when the contents of the bladder are voided. Incorrect functioning due to premature relaxation of such sphincter muscles can be problematic, and in the case of stress urinary incontinence (malfunction of the urethral sphincter) highly distressing to the patient.
Premature relaxation of a sphincter muscle often occurs when the Sphincter muscle itself lacks sufficient bulk to adequately close the orifice in question. One option to overcome the problem is by implanting bulking material in the submucosa surrounding the orifice, thereby reducing the area to be closed by the sphincter muscle. Generally, the bulking material is injected into the site to augment the soft tissue present. Suitable bulking materials are available commercially and are generally in the form of spherical particles or beads based on silicone, PTFE or collagen. These beads are suspended in a carrier fluid such as glycerine or hydrogel. The carrier fluid ants as a lubricant during the implantation process and assists expulsion of the implant from the syringe through an endoscopic needle. The carrier fluid is eliminated from the body and the implant material gradually becomes encapsulated by collagen at the implant site. The collagen capsule which forms around the implanted material adds to the bulk at the site. One such bulking material is MACROPLASTIQUE (Trade Mark) of Uroplasty, Inc.
Existing implants do not biodegrade but remain permanently in the body of the patient. Recently, concern has been raised that such implants may gradually migrate away form the site of implantation during the lifetime of the patient. Thus, the original problem may recur as the size of the implant gradually decreases due to migration of the beads inserted. The patient will therefore need to undergo a further procedure in order to insert more beads at the site concerned The migrating implant may, in addition, cause irritation and such implants have been reported to be associated with cancer, auto-immune and connective tissue disease.
In addition to stress urinary incontinence, such implants have also been used to prevent vesicoureteral reflux. Vesicoureteric reflux is a condition occurring in babies and small children where the ureteral orifice is incompletely closed during contraction of the bladder. Urine is thus allowed to reflux back up the ureter and can cause recurrent infections of the kidneys, frequently leading to permanent kidney damage. In a similar manner to stress urinary incontinence, it is possible to insert pellets or beads of silicone rubber or teflon in the submucosa of the bladder wall close to the ureteral orifice. Again, the procedure requires the permanent insertion of the implant.
Paediatric vesicoureteral reflux usually resolves itself as the bladder wall thickens. By the time a child is five years old the urinary system has usually matured sufficiently to make the implant material redundant. Again, it is possible for implant material to migrate from the implant site causing obstruction, occlusion or embolism at another site. Implants have also been associated with cancer, auto-immune and connective issue disease.
The present invention provides a composition suitable for implantation in soft tissue (for example at or around a body orifice) in order to augment the volume of soft tissue. The composition of the present invention comprises particles of biodegradable glass in a suitable carrier medium. The carrier medium is required to ensure easy injection at the site of interest.
The currently available silicone, PTFE and collagen beads are all deformable. This property aids injection of the beads, butalso contributes to their ability to migrate from the site of interest. By contrast, the glass particles of the present invention are non-deformable.
The composition is suitable for insertion in the bladder submucosa to treat stress urinary incontinence or vesioureteric reflux by bulking up the area around the urethral sphincter or urethral orifice respectively.
Optionally, the glass particles dissolve over a relatively long period, typically one to five years, more usually one to two years.
Preferably, the glass particles are irregularly shaped. This contrasts to the commercially available implants which are formed from spherically shaped beads. The irregular shape of the glass particles encourages their encapsulation in fibrous tissue. Such encapsulation further reduces the rate of dissolution of the glass and also helps to prevent migration of the particles.
Typically, the glass particles used in the present invention may have a diameter of from 50 &mgr;m up to 2000 &mgr;m. More conveniently, however, the average diameter of the particles will be 1000 &mgr;m or less, usually 500 &mgr;m or less. Good results have been obtained with particles having an average diameter of 300 to 200 &mgr;m or less, for example 150 &mgr;m or less.
Particles having smaller diameters, e.g. 100 &mgr;m or less, particularly of approximately 50 &mgr;m, or even less, are of especial interest.
One advantage of the present invention is that it is possible to form glass particles having such small diameters (e.g. 50-100 &mgr;m). Where such small particles are used that problems associated with injection are reduced. Additionally, once the particles have been located in the site of interest, the outside surfaces of the particles becomes tacky as the particles begin to dissolve into body fluids so that the particles become associated in situ in a sticky cohesive mass.
Such particle association greatly reduces the rate of particle migration and the health risks associated therewith. No such association has been observed with the prior art silicone, PTFE or collagen beads.
A carrier medium is generally used to assist injection of the particles. The carrier medium is typically glycerol, but other conventional carrier mediums (e.g. corn oil, sesame oil, sunflower oil or olibas oil) may also be used. A surfactant and/or suspending agent may also be included in the composition. Typical surfactants include, for example, benzyl benzoate, ethyl oleate and benzyl alcohol. Typical suspending agents include, for example, carboxymethylcellulose and alginate.
In a further aspect the present invention provides a method of augmenting an area of soft tissue in a body (e.g. thickening a wall of a body organ), said method comprising injecting a composition into the soft tissue (e.g. the submucosa of said wall), said composition comprising particles of a biodegradable glass.
Thus, the present invention provides a method of combatting vesicoureteric reflux by injecting a composition of the present invention into the bladder submucosa close to the ureteral orifice such that urine is substantially unable to pass up the ureter upon contractor of the bladder.
Likewise, if the composition of the present invention is injected into the submucosa in the vicinity of the urethral sphincter, stress urinary incontinence may be overcome due to the “bulking” effect of the injected particles.
The present invention may be used at other body areas where soft tissue augmentation has a beneficial effect. Examples include injection around the anal passage, in order to reduce blood flow at the site and hence combat development of haemorrhoids (piles). Likewise soft tissue augmentation may be beneficial to temporarily correct an “incompetent” cervix which would prevent sustainment of a pregnancy. The soft tissue augmentation of the present invention may further be used to build up portions of the body damaged by accident or surgery, allowing healing to take place. Particular mention may be made of reshaping the facial area of a patient. From the above examples it is clear that the composition of the
Dees Jose′ G.
Fox Rothschild O'Brien & Frankel LLP
George Konata M
Giltech Limited
Quinn, Esq. Charles N.
LandOfFree
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