DRUG-CONJUGATES FOR SELF-ASSEMBLED NANOPARTICLES IN ANTICANCER TREATMENT

This dissertation is an overview on the functionalization of known anticancer compounds in order to form different drug-conjugates able to self-assemble in water to form nanoparticles. This approach is useful to improve the drug delivery properties and pharmacokinetic profile of anticancer drugs. All the described conjugates, except for the ones illustrated in chapter 5, have the same general structure: the anticancer drug is connected to the self-assembly inducer trough a linker. Chapter 1 regards a general introduction about nanomedicine, the advantages of the use of nanotechnology-based systems in cancer treatment and the benefits of nano- formulated drugs in the improvement of drug-delivery. Furthermore, nanoparticles are presented with a focus on their classification, characterization and preparation techniques. Chapter 2 regards the preparation of different types of self-assembled nanoparticles using various anticancer compounds and dyes but with the same lipophilic tail as self- assembling inducer: squalene. Different natural anticancer compounds such as paclitaxel, cyclopamine and doxorubicin and dyes, as fluorescein and tetramethylrhodamine, were functionalized to obtain squalene-based conjugates. Both hetero-nanoparticles composed by two drug-conjugates and drug- and dye-conjugates were prepared and tested. Chapter 3 is focused on the importance of the self-assembly inducer and describes the preparation of new conjugates containing an active moiety as self-assembly inducer. In particular, in this section, is described the preparation of conjugates composed by aloin or podophyllotoxin as active compounds and 4-(1,2-diphenylbut-1-en-1-yl) aniline, an analog of the know anticancer compound tamoxifen, as self-assembly inducer. Chapter 4 highlights the influence of the linker between the active compound and the self-assembly inducer to obtain an effective release of the free drug. In particular, it is described the synthesis of a new self-immolative linker able to trigger the drug release in particular conditions, specifically in the presence of a lipase. This linker was used for the preparation of two conjugates containing the known anticancer compound N- desacetylthiocolchicine. Chapter 5 concerns the preparation of dual drug-conjugates able to form nanoparticles without the presence of a self-assembly inducer. These conjugates have a symmetrical structure: two molecules of the same drug are linked by a chain able to guarantee the drug release in particular conditions. The natural anticancer compounds involved in the preparation of this type of conjugates are paclitaxel, epothilone A, podophyllotoxin and camptothecin and the linker used contain a disulfide moiety able to be cleaved in cellular environment.