Nanoparticles for delivery of a pharmacologically active agent

Core-shell nanoparticles compris<WC 1>e: <SL> <LI>(a) a core which comprises a water insoluble polymer or copolymer, and <LI>(b) a shell which comprises a hydrophilic polymer or copolymer; </SL> '''said nanoparticles being obtainable by emulsion polymerization of a mixture comprising, in an aqueous solution, at least one water-insoluble monomer (especially a styrenic, <WC 1>acrylic or methacrylic monomer) to form the core and either: <SL> <LI>(i) a monomer of formula (I): wherein R<1> represents hydrogen or methyl, and R<2> represents -COOAOH, -COO-A-NR<9>R<10> or -COO-A-N<+>R<9>R<10>R<11> X<->, in which A represents C1-20 <WC 1>alkylene, R<9>, R<10> and R<11> each independently represent hydrogen or C1-20<WC 1> alkyl and X represents halogen, sulphate, sulphonate or perchlorate, and a water-soluble polymer of formula (II) wherein R<3> represents hydrogen or methyl, R<4> represents hydrogen or C1-20 alkyl, and n is an integer such that the polymer of formula (II) <WC 1>has a number-average molecular weight of at least 1000; or <LI>(ii) a hydrophilic copolymer which comprises repeating units of formulae </SL> (III) and (IV): <PC>wherein R<5> and R<7> each independently represent hydrogen or methyl, R<6> represents hydrogen, -A-NR<9>R<10> or -A-N<+>R<9>R<10>R<11> X<->, which A represents C1<WC 1>-20 alkylene, R<9>, R<10> and R<11> each independently represent hydrogen or C1-20 alkyl and X represents halogen, sulphate, sulphonate or perchlorate and R<8> represents C1-10 <WC 1>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.