Polysaccharide compositions for use in tissue augmentation

Abstract

A composition of matter and method for preparation of a tissue augmentation material. A polysaccharide gel composition is prepared with a programmable rheology for a particular selected application. The method includes preparing a polymeric polysaccharide in a buffer to create a polymer solution or gel suspending particles in the gel and selecting a rheology profile for the desired tissue region.

Description

CROSS-REFERENCE TO RELATED PATENT APPLICATION [0001] The present application is a continuation-in-part of U.S. patent application Ser. No. 11 / 348,028, filed Feb. 6, 2006 and incorporated herein by reference in its entirety.FIELD OF THE INVENTION [0002] The present invention relates generally to tissue augmentation, and more particularly to injection of resorbable, biocompatible, solid composites to correct and augment soft tissue defects with specific application for cosmetic augmentation of tissues. BACKGROUND OF THE INVENTION [0003] There are a number of non-resorbable, particle-based compositions used for permanent correction or augmentation of soft tissue defects or augmentation for cosmetic purposes. Each composition is associated with certain advantages and disadvantages. [0004] Silicone gel was frequently used to treat dermal defects, such as wrinkles, folds, and acne scars in the 1970's and 1980's but has since been prohibited from use in these applications. Silicone was fre...

AI Technical Summary

Problems solved by technology

This composition has been withdrawn from commercial application due to frequent chronic inflammation and tissue rejection.

In addition, the composition is associated with sterilization challenges; the bovine collagen dispersion is damaged by standard terminal sterilization techniques, including heat and gamma irradiation.

The combination of water and an appropriate water-soluble suspending agent renders the corresponding magnetorheological material highly non-Newtonian, thereby inhibiting the settling of particles in spite of their high density and large size.

As a result, the prior art fails to address several problems with current gels.

First, the injectable materials of the prior art fail to address the specific difficulties in applying implants across a wide range of locations in the body and fail to provide the appropriate type of implant.

For example, current implants can experience occlusion, or irregular implantation during the implantation procedure when a fine gauge needle is used.

Furthermore, the propensity for occlusions often results in uneven, erratic and discontinuous implantation, which causes highly undesirable results.

Second, current implants have failed to address the viscoelastic properties of the implant in the syringe, such that current implants require a significant amount of force, and even irregular levels of force, to extrude the implant from the needle, much more so as the needle gauge is reduced.

This presents fatigue issues for medical professionals who may well be performing many injections in a day and also makes any given injection more difficult to perform, and also perform proper injection amounts and distributions, because of the necessity to exert a large amount, or an irregular amount of force on the syringe, while maintaining a steady needle during injection.

Third, current implant materials fail to address the wide range of distinctions in the different tissues in which the implants are placed.

Implants can undergo unwanted agglomeration, chemical reaction, phase separation, and premature breakdown of the implanted mass into discontinuous variable shapes, all of which can consequently manifest different undesirable mechanical properties and performance relative to the implant tissue region.

In particular, prior art implants utilizing gels have relied on the gel as a carrier but have failed to recognize and solve the problem of providing an implant with a gel which is designed to cooperate with the solid particles to approach and / or be compatible with the mechanical properties of the tissue into which it is injected and to behave in a symbiotic controlled manner when embedded in the tissue.

Implants using these prior art gels exhibit a tendency to form nodules, in certain tissues, such as lips, or to migrate from the desired implantation location, or to undergo unwanted and undesired chemical and / or mechanical breakdown, such as phase separation or formation of unwanted geometries and cosmetic appearance in the body.

None of these are an acceptable result for a patient.

Images