Process for manufacturing a stationary state of crystalline polymer of a biodegradable polymer matrix carrying an active substance and a polymer matrix produced thereby

A method for manufacturing a storage stable stationary state of polymer crystallinity of an active substance charged polylactide matrix for a stent, the method comprising:

• (i) preparing the active substance charged polylactide matrix containing,
• (a) a semicrystalline polylactide, wherein the polylactide has a glass transition temperature TG of from 60-70° C. and a melting temperature TS of from 170-180° C., with an average TG and TS, (TG+TS/2) of 115° C. to 125° C., where TG represents a glass transition temperature and TS a melting temperature of the crystallites of the polylactide, and
• (b) at least one active substance, wherein the active substance charged polylactide matrix is on a surface or in a cavity of the stent communicating with the surface;
• and
• (ii) heating the active substance charged polylactide matrix to a temperature ranging from 45° C. to 55° C. for one week to form the storage stable stationary state of polymer crystallinity of the active substance charged polylactide matrix containing less than 10% by weight of amorphous polymer domains that can be crystallized at room temperature based on the total weight of polylactide, and wherein an active substance elution is increased compared to an active substance elution of a polylactide matrix without heating.