Surgical Tissue Sealant (STS)

Certain tissue adhesives and sealants that seek to avoid the limitations of sutures, staples, pins and screws have been developed and marketed for a number of years outside the United States by other parties. In the United States, approved products have fallen into several categories. DermaBond®, a synthetic cyanoacrylate adhesive, is approved for topical application to close skin incisions and lacerations. Cyanoacrylate adhesives set fast and have high strength, but form brittle plastics that do not resorb. This limitation restricts their use to bonding the outer surfaces of skin together. Tisseel®, a fibrin sealant, is approved for use as an adjunct to hemostasis in surgery. Fibrin sealants have excellent hemostatic properties, but are derived from human and/or animal blood products, set slowly, have low strength, and lose their strength rapidly.

A third category of tissue adhesives combines natural proteins such as collagen or albumin with synthetic cross-linking agents such as gluraraldehyde. Such products were originally marketed in Europe for limited, life-threatening indications and the FDA approved one such product, BioGlue®, in 2001 for use as an adjunct to sutures and staples in vascular surgery to repair large arteries. The aldehyde cross-linking agents employed in such products (i.e., glutaraldehyde, formaldehyde) are known to cause adverse tissue reactions. DuraSeal®, a sealant product composed of a synthetic polymer called polyethylene glycol, is a relatively weak sealant approved for use in neurosurgery. To date, none of the products available in the U.S. for use inside the body have found widespread acceptance among surgeons, for reasons ranging from their lack of performance (based on properties such as adhesiveness, flexibility, and resorption rate), complexity of use, or concerns about the perceived benefit to risk.

PPTI has developed surgical adhesives and sealants that are easy for the surgeon to use, and that combine the biocompatibility of fibrin glues (without the risks associated with use of blood-derived products) with the high strength and fast setting times of cyanoacrylates. Unique features include significant strength and elasticity within the adhesive matrix (to move as tissues move) and the capability of tailoring the resorption rate of the adhesive matrix to the rate at which the wound heals. A non-resorbable adhesive or sealant can only be used where the damaged tissues are not going to grow together. Otherwise, a barrier to wound healing is unavoidably created.

PPTI has demonstrated both the adhesive performance and the biocompatibility of its product formulations in preclinical studies, including resorption of the adhesive matrix in conjunction with the progression of wound healing. As a result of our evaluations of the unmet surgeon needs, the properties achievable with our technology, and the capabilities of competitive technologies, specific applications providing the most significant opportunities have been targeted. One of the identified opportunities resulted in the formation of Spine Wave, Inc. and the Company’s partnership with them for the development of spinal applications of the technology. Additional preclinical studies are being conducted to support the establishment of strategic development and commercialization partnerships to capitalize on other identified opportunities.

 

Excellent Sealant Performance/Properties

• Sets quickly to an adhesive hydrogel.
• Adheres well to tissue, seals gas and fluid leaks.
• Minimal material swelling.
• Resorbable and non-resorbable formulations.
• Two absorption rates.
• Reduces post-operative adhesions.

PPTI’s tissue adhesive technology combines a silk-elastin protein polymer designed specifically to react with a biocompatible cross-linking agent under physiological conditions. Two fluid components are mixed just prior to their delivery to the treatment site, which can be accomplished through a fine gauge needle and in spray form. The material then rapidly cures to a tough, elastic hydrogel that strongly adheres to surrounding tissues.