Abstract: A responsive polymer network exhibiting the property of reversible gelation in response to a change in an environmental stimulus is provided. The aqueous solution of the network polymer, comprises about 0.01 to 20 wt % by weight of a responsive component and about 0.01 to 20 wt % by weight of a structural component capable of supporting and interacting with the responsive component. The aqueous composition exhibits at least a five-fold increase in viscosity upon gelation. The gelation may be triggered by a change in an environmental stimulus, such as temperature, pH and ionic strength.

Abstract: System for delivery of a biologically active substance into an environment. First and second chambers are separated by a moveable partition. The first chamber includes a polymer gel network which undergoes a volume change in response to an environmental condition such as pH. The first compartment includes a screen or membrane for confining the polymer gel network while allowing communication with fluid in an environment. The second compartment contains a biologically active compound or drug which is delivered to the environment through an orifice in the second compartment. Upon the occurrence of the triggering environmental condition, the polymer gel network undergoes a volume change which moves the moveable partition expelling the drug through the orifice. Drug delivery is initiated and continues only when the appropriate environmental condition or trigger is met.

Abstract: Polymer gel networks loaded with biologically active solutes in a manner that solute activity is maintained and protected from thermal and/or chemical degradation while in the gel network are provided. The invention also provides for effects of modulating parameters for loading safe responsive gel networks using loading solutions containing phase separating polymers.

Abstract: A method of loading a drug into a crosslinked polymer network and protecting the drug from the effects of inactivation is described. The method includes the steps of contacting a biologically active solute (e.g. drug) with: (i) a gel network; (ii) a loading polymer that is somewhat immiscible with the gel; and (iii) a salt, under conditions sufficient for the biologically active solute to selectively partition into the gel and the salt and the loading polymer to be entrained in the gel. A drug delivery system including a polymer gel network and the drug to be delivered is also described. The system also includes a salt and/or a loading polymer. The system protects the drug from loss of activity. In one embodiment, the polymer gel network is capable of expanding or collapsing in response to a change in an environmental condition to which the gel is exposed, the expanding or collapsing sufficient to release the drug into an environment of use.

Abstract: System for delivery of a biologically active substance into an environment. First and second chambers are separated by a moveable partition. The first chamber includes a polymer gel network which undergoes a volume change in response to an environmental condition such as pH. The first compartment includes a screen or membrane for confining the polymer gel network while allowing communication with fluid in an environment. The second compartment contains a biologically active compound or drug which is delivered to the environment through an orifice in the second compartment. Upon the occurrence of the triggering environmental condition, the polymer gel network undergoes a volume change which moves the moveable partition expelling the drug through the orifice. Drug delivery is initiated and continues only when the appropriate environmental condition or trigger is met.

Abstract: A method of loading a drug into a crosslinked polymer network and protecting the drug from the effects of inactivation is described. The method includes the steps of contacting of a biologically active solute (i.e., drug) with:(i) a gel network; (ii) a second protectant polymer that is somewhat immiscible with the gel; and (iii) a protectant salt, under conditions sufficient for the biologically active solute to selectively partition into the gel and the protectants to be entrained in the gel. Most preferably, the gel network is a crosslinked gel responsive to a change in an environmental condition to which the gel is exposed.