Patent ID: 9108001
Filing Date: 2015-08-18
Classification: A61M

Abstract:
1. A drug delivery device comprising: a housing with a proximal end and a distal end, a cartridge holder adapted to retain a cartridge, the cartridge holder comprising an at least partially transparent side wall, a piston rod, the piston rod being adapted to drive a piston so as to engage the piston into the cartridge, and a plurality of symbols on the piston rod, the symbols representing dosage information during operation of the drug delivery device and being visible through a window aperture in the housing or in the cartridge holder wherein a filling status of the drug delivery device is recognizable by viewing at least one of the symbols on the piston rod through the window aperture wherein only one symbol is viewed through the window aperture at a time on the piston rod and this particular viewed symbol represents an amount of medicinal product delivered wherein the at least partially transparent side wall of the cartridge holder comprises a plurality of structural elements located on an inner surface of the side wall, the structural elements being transparent and being capable of unevenly reflecting light so as to at least partially render the symbols of the piston rod unreadable, wherein the structural elements comprise facets, undulating elements, or grooves.