A compound of Formula I or a pharmaceutically acceptable salt thereof, or a tautomer thereof, wherein G1, G2, and B are as defined in the application, are selective inhibitors of MMP-13. Polymeric salt bridges are formed in place in capillaries or microchannels. In addition, the system may include a one way check valve to allow air upstream of the safety valve to bleed out of the brake system when the safety valve is closed before the emergency brakes for the trailer are set by the driver. , a flange or bracket, that is fixed to the vehicle.