Abstract: The present invention describes site-specific biomolecular complexes comprising a therapeutic, prophylactic and diagnostic agent, called also biologically active molecule and an omega-3 fatty acid and derivatives thereof. The complexes are further covalently bonded with cationic carriers and permeabilizer peptides for delivery across the blood-brain barrier and with targeting moieties for uptake by target brain cells. Said complexes are particularly useful for delivery of a biologically active agent to the glial tissue of the brain as well as to the cortical, cholinergic and adrenergic neurons. The preferred therapeutic complexes or conjugates comprise an omega-3 fatty acid such as alpha-linolenic acid, eicosapentaenoic acid or docosahexaenoic acid and derivatives thereof.

Abstract: A method is disclosed for delivering biologically active agents to a mammalian brain by administering a complex of the biologically active agent with a polycationic carrier coupled to 2-20 eicosapentaenoic acid or docosahexaenoic acid moieties and additional eicosapentaenoic acid or docosahexaenoic acid moieties. The polycationic carrier is poly-lysine, poly-arginine or poly-ornithine of 5-50 amino acid residues. The addition of a targeting moiety selected from tetanus toxin C fragrant, .alpha.-bungarotoxin and nerve growth factor to the complex facilitates delivery of the biologically active agent to glial tissue, or to cortical, cholinergic and adrenergic neurons.