Adjustable dose drug delivery system

An adjustable dose drug delivery system comprising:

• a plunger, a syringe body, an inner housing, a plunger sleeve, an outer housing, a rotating collar and a locking collar, wherein
• the plunger comprises a stopper at a distal end, a plunger flange comprising a center at a proximal end, and a plunger stem fixed to the center of the plunger flange at the proximal end;
• the syringe body is glass and comprises a syringe tip at a distal end and an open proximal end comprising a syringe body flange,
• wherein the plunger is slidably deposed by inserting the stopper into the open proximal end of the syringe body and pushing the plunger flange toward the syringe body distal end;
• the inner housing comprises a proximal end and a distal end and encloses the syringe body and is affixed thereto,
• wherein the inner housing further comprises a plurality of dosage stops spirally deposed between the inner housing proximal end and distal end;
• the plunger sleeve is distal to the plunger flange, and has a circumference within a plunger flange circumference and distal thereto, and encloses, and is external to, the plunger stem, and is deposed outside the inner housing and, when pushed toward the syringe body distal end, slides along the inner housing toward the plurality of dosage stops,
• wherein the plunger sleeve further comprises
• a closed slot running parallel to the plunger stem, and
• a dosage stop engagement mechanism that engages a dosage stop when the plunger sleeve slides along the inner housing, said engagement preventing (a) further sliding of the plunger sleeve along the inner housing and (b) further insertion of the plunger toward the syringe body distal end,
• wherein the dosage stop engagement mechanism comprises
• an inwardly directed locking finger at the distal end of the plunger sleeve engaging an outwardly directed knob at the dosage stop,
• and an outwardly and distally directed ramp proximal to the knob, with a gap between the ramp and the knob so that the locking finger ascends the ramp and drops into the gap when the plunger sleeve moves distally along the inner housing to the dosage stop corresponding to the dosage indicated in the window;
• the outer housing encompasses the inner housing and comprises a proximal end overlapping and deposed outside the plunger sleeve;
• the rotating collar surrounds the plunger sleeve and the proximal end of the outer housing and is rotationally joined to the plunger sleeve by a pin in the rotating collar inserted into the plunger sleeve closed slot, wherein
• the rotating collar further comprises a window displaying dosage information present on the outer housing, and
• rotating the rotating collar displays a series of specific dosages in the window and rotates the plunger sleeve to align the dosage stop engagement mechanism to a dosage stop on the inner housing corresponding to the specific dosage displayed in the window;
• the locking collar surrounds the plunger sleeve and the proximal end of the outer housing adjacent to the rotating collar and rotationally joined thereto, wherein
• the rotating collar is initially separated from the locking collar by a gap, wherein closing the gap engages a locking mechanism preventing rotation of the rotating collar and plunger sleeve,
• wherein the locking mechanism comprises inwardly directed tabs on the locking collar nearest to the outer housing engaging notches in the outer housing at the position of each dosage stop;
• the system further comprising an initial stop mechanism preventing, without rotating the rotating collar to display dosage information, (i) sliding of the plunger sleeve along the inner housing toward the plurality of stops and (ii) insertion of the plunger toward the syringe body distal end,
• wherein the initial stop mechanism is (A) a protrusion on the inner housing above the dosage stops, and (B) open slots in the plunger sleeve extending from near the proximal end and opening at the distal end of the plunger sleeve,
• where the open slots align with the protrusion when the rotating collar is rotated to display a specific dosage in the window allowing the plunger and the plunger sleeve to slide to the dosage stop corresponding to the dosage displayed.