The invention relates to unsaturated polyester resins and more particularly polyester resin compositions curable at room temperature and comprising divinyl ethers. The foamable pharmaceutical composition comprises a corticosteroid compound as an active ingredient; a quick-break foaming agent including an aliphatic alcohol, water, a fatty alcohol and a surface active agent; a buffering agent; and a propellant. Further, an embodiment of the present invention may provide at least one T connector between the cross connector and at least one of the plurality of ports, wherein at least one tunable dielectric capacitor may be associated with the T connector to vary the impedance in at least one node of the T connector.