Abstract: A nucleic acid complex for delivering a nucleic acid or a derivative thereof to a cell comprises the components: A. a nucleic acid or a derivative thereof; B. a cationic polymer; and C. a preformed polyethylene glycol-cationic polymer copolymer. The complex has a conformation in which the nucleic acid or derivative thereof is condensed and wherein component C is bound to component A such that the poylethylene glycol groups of component C are located at the surface of the complex. The complexes which are stable to aggregation are useful for the delivery of nucleic acids or derivatives thereof to cells in biological systems.

Abstract: A process for attaching a polyethylene glycol compound to a macromolecule to prepare a conjugate or adduct between the polyethylene glycol compound and the macromolecule is described. The process comprises the steps of (1) preparing an activated PEG or an activated PEG derivative by incorporating an acrylic ester, an acrylic thioester or an acrylamido group into the PEG or PEG derivative; (2) reacting the activated PEG or PEG derivative with a macromolecular material comprising one or more sulphydryl groups, primary amino groups and/or secondary amino groups and (3) recovering the conjugate of the PEG or PEG derivative and the macromolecular material.

Abstract: A composition for delivering a biologically active polyanionic molecule comprising a linear polymer with a backbone comprising amido and tertiary amino groups arranged regularly on the backbone and biologically active polyanionic molecule bound to the polymer. Preferably, the linear polymer comprises a poly(amidoamine). Preferably, the biologically active polyanionic molecule is a nucleic acid, more preferably a DNA. The compositions are useful for delivering nucleic acids to a cell in a cell transformation, transfection or gene therapy method.