>Magister Scientiae - MSc / HIV and AIDS are among the world's pandemics that pose serious concern to almost every individual in the world. With the current level of availability of anti-retroviral (ARV) drugs and the ease of accessibility of treatment in many countries such as South Africa, the disease can be controlled by suppressing the viral load of an infected individual. These anti HIV drugs such as delavirdine are metabolised by enzymes which are found in the liver microsomes, particularly those of the cytochrome P450 family. Due to the fact that the metabolic rate of a patient determines the effect of the drug, the drug could either have a beneficial or an adverse effect once it is administered. It is therefore imperative that the metabolic profile of a patient is determined at point-of-care is necessary for proper dosing of the ARV drugs. In this project a nanobiosensor system was devised and used for the determination of the metabolism of delavirdine, a non-nucleoside reverse transcriptase inhibitor (NNRTI) ARV drug. The nanobiosensor was prepared by the entrapment of the isoenzyme CYP3A4 into a pre-formed electro active carrier matrice consisting of a dendrimeric copper generation-2 poly (propylene imine)-co-polypyrrole star copolymer (Cu(G2PPI)-co-PPy). The metallo-dendrimer was used as a host for the enzyme and provided thenecessary bio-compatible environment that allowed the direct transfer of electrons between the enzyme's active centres and platinum electrode surface. Copper was the choice of metal used in the study due to its properties. Copper is a malleable, ductile and a good conductor of both heat and electricity. It is a better conductor than most metals. Silver which also belongs to group 1b in the periodic table is a better electrical conductor than copper but copper has better corrosion resistance and is a more abundant and hence it is a cheaper material to use. Cu(G2PPI)-co-PPy was prepared by the incorporation of the copper metal into the G2PPI and the electropolymerization of pyrrole onto the Cu(G2PPI). The incorporation of Cu into G2PPI was determined by FTIR which did not show the presence of the Cu but showed an increase in the intensities of the peaks after the incorporation. The surface morphology of Cu (G2PPI) was confirmed by the use of HRSEM which showed a difference in the surface morphology of the dendrimer moiety with the addition of the copper metal. The HRSEM images after Cu incorporation resulted in the change from rough surface to smooth surface with open cavities which were essential for the entrapment of the biological systems (CYP3A4). Energy dispersive spectrometry (EDS) and HRTEM were used to confirm the presence of spherically shaped copper nanoparticles in the Cu (G2PPI) and were found to have a size distribution of 12-17 nm with an average particle size of 15nm. The star copolymer (Cu(G2PPI)-co-PPy) was characterised using cyclic voltammetrywhere it was confirmed that the material was electroactive and conducting due to electron movement along the polymer chain. A diffusion co-efficient (D₀) value of 8.64 x 10⁻⁵ cm²/s was determined for the material indicating a slow electron transfer kinetics within the diffusion layer. The constructed nanobiosensor was developed using copper poly (propylene imine) – polypyrrole star copolymer, bovine serum albumin and glutaraldehyde coupled to the enzyme CYP3A4. The resultant nanobiosensor parameters include a dynamic linear range (DLR) of 0.01-0.06 nM, a limit of detection (LOD) of 0.025 nM and a sensitivity value of0.379 μA/nM.

Submitted by Cláudia Bueno (claudiamoura18@gmail.com) on 2016-04-04T18:58:10Z No. of bitstreams: 2 Dissertação - Antônio Silva Machado - 2015.pdf: 1923171 bytes, checksum: 991e35e30785c0ac34b0f9290b2fc249 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-04-05T10:37:58Z (GMT) No. of bitstreams: 2 Dissertação - Antônio Silva Machado - 2015.pdf: 1923171 bytes, checksum: 991e35e30785c0ac34b0f9290b2fc249 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-04-05T10:37:58Z (GMT). No. of bitstreams: 2 Dissertação - Antônio Silva Machado - 2015.pdf: 1923171 bytes, checksum: 991e35e30785c0ac34b0f9290b2fc249 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-03-10 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / AIDS is considered an epidemic disease shaping up as a serious public health problem. Since its discovery in 1981, considerable efforts have been made to better understand the HIV infection mechanism thus, propelling the research and drug development process. According to their mechanism of action, HIV drugs can be classified into six mainly subgroups: nucleoside reverse transcriptase inhibitors (NRTIs), protease inhibitors (PI), non-nucleoside reverse transcriptase inhibitors (NNRTIs), nucleotide reverse transcriptase inhibitors (NtRTI ), entry inhibitors and integrase inhibitors. Currently, searching for safer and more effective drugs showing less collateral effects remains an encouraging pace. In this context, our work describes a synthesis of a new family of heterocyclic compounds, chemically related to delavirdine, a NNRTIs currently used in AIDS treatment. Bioisosterism strategy was applied to obtain synthetic products (54a-54h) in four steps only. Conventional heating method (A) and optimized microwave reactor (B) methodology were both compared by means of their intermediate products yields. Results showed increased yields of partial products (20a-20h [91-98%]); (29a-29h [69-88%]); (37a-37h [82-92%]) for microwave reactor methodology, as well a gain in the time spent during the procedure. All compounds (20a-20h; 29a-29h; 37a-37h e 54a-54h) were characterized by Nuclear Magnetic Resonance of Hydrogen (1H NMR), Carbon (13 C NMR) and Infrared spectroscopy (IR). / A Aids é considerada uma epidemia de cunho global, se configurando como um grave problema de saúde pública. Desde de sua descoberta em 1981, foram realizados esforços consideráveis para a melhor compreensão do mecanismo pelo qual o HIV propicia a infecção, iniciando o processo de pesquisa e desenvolvimento de fármacos. Sendo estes classificados de acordo com os seus mecanismos de ação, apresentados em 6 grupos i.e inibidores nucleosídicos da transcriptase reversa (NRTI), inibidores da protease (PI), inibidores não nucleosídicos da transcriptase reversa (NNRTI), inibidores nucleotídeos da transcriptase reversa (NtRTI), inibidores de entrada e inibidores de integrase. Logo, a busca por novos fármacos que sejam mais efetivos, seguros e com menos efeitos coletareis é de grande relevância. Neste contexto, o trabalho descreve a síntese de uma nova família de compostos heterocíclicos, planejados estruturalmente a partir do fármaco delavirdina - atualmente empregada no tratamento da AIDS, atuando como inibidor não nucleosídico da transcriptase reversa. Os compostos finais sintetizados (54a-54h) são obtidos em quatro etapas sintéticas. Estas foram planejadas e seus rendimentos comparadas a partir da estratégia de bioisosterismo. Seus intermediários foram sintetizados tanto por metodologia de aquecimento convencional (A) assim como, por reator de micro-ondas (B). Os resultados obtidos demonstraram aumento do rendimento parcial (20a-20h [91-98%]); (29a-29h [69-88%]); (37a-37h [82-92%]) e ganho de tempo na síntese dos intermediários, pela metodologia otimizada por reator de microondas. Todos os compostos (20a-20h; 29a-29h; 37a-37h e 54a-54h) foram caracterizados por meio de ressonância magnética nuclear de Hidrogênio (RMN 1H), de Carbono (RMN 13C) e espectroscopia de infravermelho (IV).