Drug-delivering composite structures

Abstract

Composite structures composed of a fibril core and a polymeric coat and designed capable of encapsulating both hydrophobic and hydrophilic bioactive agents while retaining the activity of these agents are disclosed. Further disclosed are processes of preparing such composite structures, and medical devices and disposable articles made therefrom.

What is claimed is: 
     
         1 . An article-of-manufacture comprising a structural element core and a polymeric coat coating at least a part of said structural element core, said coat comprises at least one bioactive agent releasably encapsulated therein, wherein said coat has a microstructure of a freeze-dried water-in-oil emulsion, said emulsion comprises, prior to freeze-drying, a dispersed aqueous solution and a continuous organic solution, said organic solution containing at least one polymer and said aqueous solution or said organic solution containing said bioactive agent; and wherein a plurality of droplets of said dispersed aqueous solution freeze-dry to form microscopic capsules in a solid form of said continuous organic solution, in a form of a plurality of pores randomly dispersed within said polymeric porous coat. 
     
     
         2 . The article of  claim 1 , wherein said bioactive agent is dissolved or dispersed in said aqueous solution or said organic solution, while retaining an activity thereof during said freeze-drying. 
     
     
         3 . The article of  claim 2 , wherein said bioactive agent is releasably encapsulated in said solid form of said continuous organic solution. 
     
     
         4 . The article of  claim 2 , wherein said bioactive agent is releasably encapsulated in said pores. 
     
     
         5 . The article of  claim 1 , wherein said polymeric coat is characterized by an average pore diameter that ranges from about 1 nm to about 1 mm. 
     
     
         6 . The article of  claim 1 , wherein said polymeric coat is characterized by an average pore diameter that ranges from 1 nm to 1 mm. 
     
     
         7 . The article of  claim 1 , wherein a thickness of said polymeric coat ranges from about 1 μm to about 2000 μm. 
     
     
         8 . The article of  claim 1 , wherein said at least one polymer is a biodegradable polymer. 
     
     
         9 . The article of  claim 8 , wherein said biodegradable polymer is selected from the group consisting of an aliphatic polyester, poly(glycolic acid), poly(lactic acid), polydioxanone (PDS), poly(alkylene succinate), poly(hydroxybutyrate), poly(butylene diglycolate), poly(epsilon-caprolactone) and any co-polymer, blend and a mixture thereof. 
     
     
         10 . The article of  claim 9 , wherein said aliphatic polyesters is selected from the group consisting of poly(L-lactic acid), poly(glycolic acid) and poly(lactic-co-glycolic acid). 
     
     
         11 . The article of  claim 1 , wherein structural element core is selected from the group consisting of a needle, a tube, a wire, a thread, a screw, a pin, a tack, a rod and a plate. 
     
     
         12 . The article of  claim 1 , wherein said structural element core is a medical device. 
     
     
         13 . The article of  claim 12 , wherein medical device is selected from the group consisting of a needle, a tube, a wire, a thread, a screw, a pin, a tack, a rod, a plate, a suture, a suture anchor, an anastomosis clip or plug, a dental implant or device, an aortic aneurysm graft device, an atrioventricular shunt, a catheter, a heart valve, a hemodialysis catheter, a bone-fracture healing device, a bone replacement device, a joint replacement device, a tissue regeneration device, a hemodialysis graft, an indwelling arterial catheter, an indwelling venous catheter, a pacemaker, a pacemaker lead, a patent foramen ovale septal closure device, a vascular stent, a tracheal stent, an esophageal stent, a urethral stent, a rectal stent, a stent graft, a synthetic vascular graft, a vascular aneurysm occluder, a vascular clip, a vascular prosthetic filter, a vascular sheath and a drug delivery port and a venous valve.