Patent ID: 7682356
Filing Date: 2010-03-23
Classification: A61K,A61M,F16J,Y10T

Abstract:
1. An osmotic delivery system for delivering an active agent formulation to a fluid environment, comprising: a reservoir comprising an interior wall defining a lumen that contains the active agent formulation and an osmotic agent formulation; and a piston assembly positioned in the lumen to isolate the active agent formulation from the osmotic agent formulation, wherein the piston assembly comprises a columnar body that (i) has a core made of a polymeric material comprising an ultra high molecular weight polyethylene, (ii) produces volatile leachates of less than about 1.4 μg/ml when exposed to benzyl benzoate at 40° C. for at least about 45 days, and (iii) further comprises a rim at a distal end thereof for engaging and sealing against the interior wall of the reservoir, and a spring retained at the distal end for biasing the rim against the wall of the reservoir.