Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 98-113).

A fotoquimioterapia (FQT) é uma técnica de tratamento de doenças graves, inclusive o câncer, que utiliza que utiliza compostos que, sendo introduzidos dentro de um organismo, não possuem alguma atividade contra ele e quando são excitados, através de luz na região espectral de 320 até 800 nm, produzem espécies reativas que induzem a morte celular. Dentre as formas desenvolvidas em FQT, a de maior destaque, e a que vem sendo mais utilizada em clínica, é a Terapia Fotodinâmica (TFD). Apesar das vantagens do uso da TFD, esta técnica possui limitações em sua eficiência, pois seu mecanismo está associado com à formação dos estados excitados do FS e do oxigênio molecular e, por isso, depende dos tempos de vida e rendimentos quânticos destes estados. Outro fator que limita a ampla aplicação da FQT na clínica é o alto custo dos FS utilizados atualmente. No grupo de fotobiofísica do Departamento de Física e Matemática da FCLRP-USP, tem-se trabalhado na busca de novos FS que possuam espécies reativas não excitados como, por exemplo, os radicais livres (peróxidos, ânion superóxido, radical hidroxila etc.), e que sejam mais viáveis economicamente em relação a outros FS já existentes no mercado. Os derivados de nitrofurano são fármacos já utilizados na rotina clínica que possuem as características promissoras para aplicação em FQT. Este trabalho dá continuidade à busca de novos FS. Escolhemos dentre inúmeros derivados de nitrofurano a Nitrofurantoína (NFT), que já é utilizada em clínica desde 1950, e que possui um custo baixo. Sua atividade fototóxica já foi documentada como reações fotoalérgicas em pacientes depois de ser administrada e nos estudos in vitro contra diversas linhagens das células neoplásicas. Contudo, os mecanismos e a dinâmica da fotoação da NFT não estavam ainda bem estabelecidas. Como objetivos gerais deste trabalho, definimos estudar a dinâmica da fotodecomposição da NFT e a liberação de radical NO em soluções aquosas, em função da composição do ambiente, tendo em vista analisar sua potencialidade para aplicação em fotoquimioterapia de diversas doenças, inclusive o câncer. Demonstramos que durante a sua fototransformação, a NFT libera o NO, e o rendimento do processo depende do estado de protonação da NFT. A liberação de NO se realiza por duas vias paralelas: liberação direta pela molécula de NFT e através da fotólise do seu fotoproduto. O estado tripleto da NFT apresenta tempo de vida (t) muito curto, provavelmente devido à participação ativa em formação de um dos fotoprodutos. Pelo fato de ser muito curto, é pouco provável que o estado T1 produza efetivamente, o oxigênio singleto. Assim, podemos associar a fotoatividade da NFT com a liberação de NO. Por fim, propusemos um esquema para a fotoliberação de NO pela fototransformação da NFT. / Photochemotherapy (PCT) is a technique applied in the treatment of serious diseases. For example in cancer, the PCT uses compounds that are introduced into an organism that do not have some activity against him, and that when are excited with light, in the spectral region from 320 to 800 nm, produces reactive species that induce the cell death. The photodynamic therapy (PDT) is the most widely used PCTtechnique in clinical applications. Despite the advantages of the use of PDT, this technique has efficiency limitations, because the PDT mechanism is associated with the formation of excited states in photosensitizer (PS) and in molecular oxygen and therefore, depends on the lifetimes and quantum yields of these states. Another limiting factor of the PDT in more PCT clinical applications is the high cost of the PS used today. The photo-biophysic group of the Department of Physics and Mathematics of the FFCLRP-USP has been working on searching of new PS without reactive species with exited states and cheaper than others PS on the market. For example, our group has investigated the free radicals: peroxide, superoxide anion, hydroxyl radical. This work continues the search for new PS. We chose the Nitrofurantoin (NFT), a nitrofuran derivative, which it is used in clinical applications since 1950 and have a low cost. The nitrofuran derivatives are drugs used in clinical applications with promising characteristics for applications in PCT. The photo-toxic activity of the NFT has been observed in photo-allergic reactions of patients and in vitro studies of several neoplastic cell lines. However, the NFT photo- action mechanisms and kinetics are not well established. The objective of this work was the study of the photo-decomposition dynamics of the NFT and the delivery of the NO radical in aqueous solutions depending on the composition of the environment, aiming to analyze its potential for application in PCT of several diseases, including cancer. In this work we demonstrated that during the photo-transformation, the NFT delivery NO and the yield of this process depends on the protonation state of the NFT. We observed that the NO delivery is made of two parallels ways: a direct delivery by NFT molecule and a delivery by photolysis of their photo-products. Probably due to the active participation in the photo-products formation we observed that the triplet state of NFT has very short lifetime (T) and therefore, it is not expected that the state T1 produces singlet oxygen. Thus, we can associate the NFT photo-activity with the NO delivery. Finally, this work proposes a scheme for NO photo-delivery using the NFT photo-transformation.

Yes / Investigations of structural reactivity, molecular interactions and vibrational characterization of pharmaceutical drugs are helpful in understanding their behaviour. The aim of this study is to determine the molecular, electronic and chemical properties of the antibiotic drug nitrofurantoin (NF), after cocrystallisation with 3-aminobenzoic acid (3ABA) and to understand how those changes lead to variation of properties in the cocrystal NF–3ABA. NF–3ABA formation is explained by stabilization via the hydrogen-bond network between NF and 3ABA molecules. It is thoroughly characterized by IR, Raman and CP-MAS solid-state 13C NMR techniques, along with quantum chemical calculations. The results of IR, Raman, and 13C NMR analyses showed that imide N–H23 and C12[double bond, length as m-dash]O of NF interact with the acid C[double bond, length as m-dash]O and –OH groups in 3-ABA, respectively. Therefore the IR, Raman, and 13C NMR spectra verified the formation of N–H⋯O and O–H⋯O hydrogen bonds. To study hydrogen bonding interactions theoretically in NF–3ABA, two functionals B3LYP and wB97X-D have been used. A comparison is made between the results obtained by B3LYP and those predicted at the wB97X-D level. It is found that wB97X-D is best applied density functional theory (DFT) functional to describe the hydrogen bonding interactions. The strength and nature of hydrogen bonding in NF–3ABA have been analysed by quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) analysis. To validate the results obtained by QTAIM theory and to study the long-range forces, such as van der Waals interactions, the steric effects in NF–3ABA, the reduced density gradient (RDG) and the isosurface have been plotted using Multiwfn software. QTAIM and isosurface analysis suggested that the hydrogen bonding interactions present in NF–3ABA are moderate in nature. The calculated HOMO–LUMO energy gap shows that NF–3ABA is more active than NF and 3ABA. Chemical reactivity descriptors are calculated to understand the various aspects of pharmacological sciences. Chemical reactivity parameters show that NF–3ABA is softer and chemically more reactive than NF. The results suggest that cocrystals can be a feasible alternative for positively changing the targeted physicochemical properties of an active pharmaceutical ingredient (API). / V. R. Vangala acknowledges the financial support of the Royal Society of Chemistry for mobility grant (2015/17).

Yes / Pharmaceutical salt, nitrofurantoin–4-dimethylaminopyridine (NF-DMAP), along with its native components NF and DMAP are scrutinized by FT-IR and FT-Raman spectroscopy along with density functional theory so that an insight into the H-bond patterns in the respective crystalline lattices can be gained. Two different functionals, B3LYP and wB97X-D, have been used to compare the theoretical results. The FT-IR spectra obtained for NF-DMAP and NF clearly validate the presence of C33–H34⋅⋅⋅O4 and N23–H24⋅⋅⋅N9 hydrogen bonds by shifting in the stretching vibration of –NH and –CH group of DMAP+ towards the lower wavenumber side. To explore the significance of hydrogen bonding, quantum theory of atoms in molecules (QTAIM) has been employed, and the findings suggest that the N23–H24⋅⋅⋅N9 bond is a strong intermolecular hydrogen bond. The decrement in the HOMO-LUMO gap, which is calculated from NF → NF-DMAP, reveals that the active pharmaceutical ingredient is chemically less reactive compared to the salt. The electrophilicity index (ω) profiles for NF and DMAP confirms that NF is acting as electron acceptor while DMAP acts as electron donor. The reactive sites of the salt are plotted by molecular electrostatic potential (MEP) surface and calculated using local reactivity descriptors. / SERB, DST, India, for providing the National Post-doctoral Fellowship (Project File Number: PDF/2016/003162); Central Facility for Computational Research (CFCR), University of Lucknow; Newton-Bhabha Ph.D. placement award (2017); Royal Society seed corn research grant (2018-19)

The developmental aspect of drug transport across the blood-brain barrier (BBB) was investigated. Microdialysis was used to study unbound morphine BBB transport at different ages in sheep. An in vitro study was performed to find differentially expressed genes in brain capillary-rich fractions of the brain in rats of different ages. Microdialysis and brain-to-plasma ratios were used to study the contribution of breast cancer resistance protein (Bcrp) to the transport of nitrofurantoin (NTF) across the BBB of rats during development as well as in adult rats and mice. A method of analysing morphine and its metabolites in plasma and microdialysis samples was developed and validated. The in vivo recovery of deuterated morphine, used as a calibrator in microdialysis experiments, was not affected by the presence of morphine in the tissue. A net influx of morphine was observed in premature lambs and adult sheep, in contrast to the efflux seen in other species. This influx decreased with age, indicating that the morphine transport across the BBB changes with age. In contrast, the transport of the morphine metabolite morphine-3-glucuronide (M3G) did not change with age. Microarray data indicated that several active transporters are differentially expressed with age. Moreover, the mRNA expression levels of Abcg2 (Bcrp) and Slc22a8 (organic anion transporter 3) changed with age when quantified using real-time polymerase chain reaction. In contrast, the expression of Abcb1 (P-glycoprotein) and occludin (a tight junction protein) did not change with age. In rats, the brain distribution of NTF decreased with age due to increased protein binding in plasma. The concentration ratio of unbound NTF across the BBB was low in the adult rat, due to intra-brain metabolism and/or efflux by other transporters. Bcrp did not appear to have a significant contribution in the developing rat or in knock-out mice compared to wild-type controls with regard to NTF BBB transport. In conclusion, in vitro studies showed that the expression levels of some genes changed with age, presumably affecting subsequent drug distribution to the brain. Further, in vivo studies showed that distribution across the BBB changed with age for morphine but not for M3G or NTF.