The invention relates to novel absorbable polyesters, produced by ring-opening polymerisation of hydroxycarboxylic acids in the presence of a polyol containing an electrolyte, in an extruder. In particular, the invention relates to novel polylactide glycolide polyesters which are essentially free of dextran sulphate and which are produced by ring-opening polymerisation of lactide and glycolide in the presence of dextran sulphate in the extruder; to the production of the same and to their use in depot medicaments.