Nanoparticles for delivery of a pharmacologically active agent

Core-shell nanoparticles comprise: (a) a core which comprises a water insoluble polymer or copolymer, and (b) a shell which comprises a hydrophilic polymer or copolymer; '''said nanoparticles being obtainable by emulsion polymerization of a mixture comprising, in an aqueous solution, at least one water-insoluble monomer (especially a styrenic, acrylic or methacrylic monomer) to form the core and either: (i) a monomer of formula (I): wherein R represents hydrogen or methyl, and R represents -COOAOH, -COO-A-NRR or -COO-A-NRRR X, in which A represents C1-20 alkylene, R, R and R each independently represent hydrogen or C1-20 alkyl and X represents halogen, sulphate, sulphonate or perchlorate, and a water-soluble polymer of formula (II) wherein R represents hydrogen or methyl, R represents hydrogen or C1-20 alkyl, and n is an integer such that the polymer of formula (II) has a number-average molecular weight of at least 1000; or (ii) a hydrophilic copolymer which comprises repeating units of formulae (III) and (IV): wherein R and R each independently represent hydrogen or methyl, R represents hydrogen, -A-NRR or -A-NRRR X, which A represents C1-20 alkylene, R, R and R each independently represent hydrogen or C1-20 alkyl and X represents halogen, sulphate, sulphonate or perchlorate and R represents C1-10 alkyl. The shell is formed by (i) or (ii). The nanoparticles may further comprise, adsorbed at the surface of the nanoparticles, at least one pharmacologically active agent, such as a disease-associated antigen The antigen may be a deoxyribonucleic acid, ribonucleic acid, oligodeoxynucleotide, oligonucleotide or protein; a microbial antigen or a cancer-associated antigen. A preferred antigen is a human immunodeficiency virus-l (HIV-1) antigen, especially an HIV -1 Tat protein or an immunogenic fragment thereof. Such materials may be used in a method of treatment of the human or animal body by therapy (especially for preventing or treating HN infection or AIDS) or in a diagnostic method practised on the human or animal body