Drug delivery through hydrogel plugs

A medical prosthesis for blocking or reducing tear flow through a punctum or canaliculus of a human eye and delivering a drug to the eye that comprises:

• a punctal plug comprising a dehydrated covalently crosslinked synthetic hydrophilic polymer hydrogel wherein the hydrogel precursors are first covalently cross-linked to form the hydrogel and then stretched in length and dried, with the plug having dimensions to pass through a puncta lacrimali, and with the dehydrated hydrogel absorbing physiological water to swell to at least 1 mm in cross-sectional width to expand the plug to conformably fit a canaliculus, with the hydrogel thereby directly contacting tissue of the canaliculus in the expanded state and having a proximal face in fluid communication with a tear film of the eye and with the punctal plug further comprising a therapeutic agent dispersed through the hydrogel for sustained release through the proximal face to the tear film of the eye in an effective amount over a period of at least about seven days,
• with the hydrogel having a water content of at least about 50% by weight or volume when allowed to fully hydrate in vitro in physiological saline and being free of polysaccharides.