A dispensing device is provided to dispense a designated amount of a material on every dose delivery operation. The dispensing device includes a thumb pad, a cam drum coupled to the thumb pad, and a pawl nut comprising a one-way pawl. The thumb pad may be pulled out in a direction away from a distal end of the dispensing device for setting a dose of the material to be dispensed out and may be pushed in towards the distal end for delivering the dose. The cam drum includes a plurality of linear cam profiles and a plurality of helical cam profiles that may be disposed on a surface of the cam drum. The one-way pawl may engage with a ratchet disposed at a distal end of the cam drum and may prevent a rotation of the cam drum in an undesired direction.