Thin strut stent from bioabsorbable polymer with high fatigue and radial strength and method to manufacture thereof

A process for preparation of a biodegradable polymer stent made of PLLA (poly-L-Lactide) with a strut thickness of less than 130 μm, comprising:

• (a) Deforming an extruded PLLA tube axially at a temperature of 70° C. to 80° C. by applying an axial force until a desired stretch is achieved and then radially expanding the tube at a temperature of 70° C. to 80° C. by pressurizing the tube with inert gas in three stages, including pressurizing at a pressure of 250-280 psi in a first stage, a pressure of 375-410 psi in a second stage, and a pressure of 500-530 psi in a third stage;
• (b) Heating the tube to a temperature between 100° C. and 110° C. after radial expansion under pressure for up to 2 min, and then cooling the tube to 20° C. in 20-30 sec to get a finished deformed tube;
• (c) Cutting a scaffold structure pattern on the deformed tube by laser machining to obtain a stent;
• (d) Annealing the laser machined stent and depositing radio opaque markers on the stent;
• (e) Cleaning the annealed stent with radio opaque markers using a solvent to remove irregularities and to achieve a smooth surface;
• (f) optionally coating the cleaned stent with a formulation of an antiproliferative drug and a carrier polymer by spray coating;
• (g) Crimping the cleaned stent on a balloon of a pre-sterilized delivery catheter in a clean environment to form a crimped stent system;
• and
• (h) Sterilizing the crimped stent system by an e-beam method with an e-beam dose less than 20 kGy.