Abstract: The present invention is directed to a composition and pharmaceutical preparations for introducing nucleic acids including oligo- or poly-nucleotide into cells in a host tissue by a delivery system and a method of preparing such a composition. The composition for delivery of nucleic acids comprises polymeric carrier particles that are essentially free of groups having a positive electric charge and the nucleic acids are provided essentially on the surface of the particles. The carrier particle is insoluble in water but suitably it is able to absorb water quickly.