Method for preparating of pharmaceutical composition

The pharmaceutical composition for the prevention of sexually transmitted diseases according to the invention is designed to be brought into contact with a mucosa. It is characterised in that it contains, on the one hand at least one agent which is active against viruses or bacteria responsible for the said sexually transmitted diseases, and on the other hand a product inhibiting penetration of the said active agent through a mucosa, in combination with a pharmaceutically acceptable vehicle suited to topical administration of this composition. Advantageously, the product inhibiting penetration is a film-forming material capable of forming a film with which the active agent or agents is/are combined.