A micropump for delivery of medication by infusion, comprising: a reservoir ; a cannula ; a motor ; a gear ; a drive rack ; a tubular pump housing having a first aperture in fluid communication with the reservoir and a second aperture in fluid communication with the cannula; a drive piston and a floating piston axially oriented within the pump housing ; the drive piston and the floating piston being positioned to close the first and second aperture at first and second axial positions, respectively, of the drive piston and floating piston within the pump housing ; characterized in that the motor is engaged to the gear and the gear is engaged to the drive rack to translate the drive piston axially with respect to the floating piston , wherein translating the drive piston with respect to the floating piston defines a pump volume space within the pump housing ; wherein the floating piston is driven by the drive piston ; and wherein the drive piston is coupled to the floating piston , and the drive rack is axially oriented with respect to the pump housing and coupled to the drive piston to translate the drive piston in the pump housing ; further comprising: a first hook on the floating piston ; a second hook on one end of the drive piston coupled to the first hook on the floating piston ; a third hook on a second end of the drive piston axially opposite said first end of the drive piston ; and a forth hook on the drive rack coupled to the third hook on the drive piston ; a gap between the first hook and the second hook permitting defined axial movement of the floating piston with respect to the drive piston ; and a gap between the third hook and the fourth hook permitting defined axial movement of the drive rack with respect to the drive piston . a reservoir ; a cannula ; a motor ; a gear ; a drive rack ; a tubular pump housing having a first aperture in fluid communication with the reservoir and a second aperture in fluid communication with the cannula; a drive piston and a floating piston axially oriented within the pump housing ; the drive piston and the floating piston being positioned to close the first and second aperture at first and second axial positions, respectively, of the drive piston and floating piston within the pump housing ; characterized in that the motor is engaged to the gear and the gear is engaged to the drive rack to translate the drive piston axially with respect to the floating piston , wherein translating the drive piston with respect to the floating piston defines a pump volume space within the pump housing ; wherein the floating piston is driven by the drive piston ; and wherein the drive piston is coupled to the floating piston , and the drive rack is axially oriented with respect to the pump housing and coupled to the drive piston to translate the drive piston in the pump housing ; further comprising: a first hook on the floating piston ; a second hook on one end of the drive piston coupled to the first hook on the floating piston ; a third hook on a second end of the drive piston axially opposite said first end of the drive piston ; and a forth hook on the drive rack coupled to the third hook on the drive piston ; a gap between the first hook and the second hook permitting defined axial movement of the floating piston with respect to the drive piston ; and a first hook on the floating piston ; a second hook on one end of the drive piston coupled to the first hook on the floating piston ; a third hook on a second end of the drive piston axially opposite said first end of the drive piston ; and a forth hook on the drive rack coupled to the third hook on the drive piston ; a gap between the first hook and the second hook permitting defined axial movement of the floating piston with respect to the drive piston ; and a gap between the third hook and the fourth hook permitting defined axial movement of the drive rack with respect to the drive piston . <EOS>