Transdermal thermal polymerization

DETAILED DESCRIPTION The present invention, in one aspect, is a method for polymerizing or crosslinking by transdermal thermal energy a perpolymer which has been placed in the body of an animal, and uses thereof.
The material to be polymerized (prepolymer) contains unsaturated functional groups which can be cross linked or polymerized using a thermally activated initiator.
For the purposes of this invention, the thermal initiator is preferably water soluble, initiates polymerization between 37 and 50.
degree.
C.
, and is nontoxic.
A suspension or solution of the prepolymer and initiator are placed subcutaneously using a syringe or through a small surgical incision.
Once the suspension or solution is in place, a heat source is placed over the site, and thermal energy from the heat source causes the material to polymerize through the action of the thermal initiator.
The thermal energy necessary to initiate the polymerization process can also be provided by the animal's own body heat, thereby eliminating the need for an external heat source.
Bioactive agents can be added to the suspension before placing it in the body of the animal, and polymerization in this case traps the bioactive agent in the polymer matrix at the site of the injection.
Biodegradation of the polymer would then allow for a gradual release of the bioactive agent over an extended time period.
In this way, the instant system is an implantable drug delivery system; however, no surgical procedure is necessary to place a preformed, drug laden implant inside the patient's body.
Other uses include tissue engineering.
Living cells can be added to the prepolymer solution, and this suspension injected into the desired tissue.
After polymerization, the cells are trapped in the polymer matrix and not able to migrate away from the site of interest.
One potential advantage of transdermal thermal polymerization versus transdermal photopolymerization is the elimination of exposure of the living cells to potentially damaging ultraviolet rays