The present invention relates to a lyophilization process for preparing a teverelix-TFA lyophilizate, said process comprises the following steps: a) providing a lyophilization suspension by mixing teverelix and trifluoroacetate at a molar ratio sufficient for providing a microcrystalline teverelix-TFA suspension without formation of a gel, and b) lyophilizating the lyophilization suspension, thereby providing a teverelix-TFA lyophilizate.
The process provides the possibility of obtaining a “pure” teverelix-TFA lyophilizate i.e. without any undesirable residues in the composition.