Closure of a medicament well

Claim 1

A closure for closing, and flushing liquid residue from an outwardly opening, peripherally walled medicament well which at a base thereof has a juncture through an opening normally closed by a backflow-preventing check-valve, with a liquid path extending generally at a right angle to the well, centrally of the tubular sidewall of cannula, said closure comprising: a plug having an axially inner end, and axially outer end and a sidewall sized to permit the plug to be telescoped into the well to a given axial extent limited by engagement of a feature on the plug with a feature on the cannula, at which the plug sealingly closes the well distally of the base of the well and leaves a medicament residue-accommodating chamber having a first given volume within the well between the axially inner end of the plug and the juncture of the base of the well; the outer end of said plug including an outwardly dished depression covered by a flexible dome wall which in a first state thereof is outwardly bulged and which is perimetrically joined to said plug so as to overlay said dished depression and form therewith in said first state thereof an enclosed, normally air-filled void having a second given volume, and which flexible dome wall in a second state thereof is internally convex towards said depression and thereby substantially diminish said void volumetrically to a third given volume; a passageway defined axially through said plug from said and through depression to and through said inner end of said plug; the difference between said second and third given volumes being substantially equivalent to the portion of said first given volume which in normal expected use of said cannula is occupied by residual medicament liquid upon conclusion of an incident of dispensing of medicament liquid through said well into said liquid path.