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The Potential of Triclabendazole in Combination with Praziquantel for the Treatment of Schistosoma mansoni Infectionssbong@murdoch.edu.au, Sze How Bong January 2007 (has links)
Previous work has suggested that triclabendazole, a member of the benzimidazole group of compounds, possessed efficacy against Schistosoma mansoni. In view of recent indications in praziquantel treatment failures and loss of sensitivity, it is imperative that new anti-schistosomals are developed as contingent treatment options, while resistance alleles, if any, remain at low frequencies. While recent studies have indicated that triclabendazole monotherapy exert weak anti-schistosomal effects, the combinatorial application of triclabendazole with praziquantel has not been explored. To assess this hypothesis, triclabendazole and its metabolites were initially assessed against the many life-stages of Schistosoma mansoni in vitro. Combinatorial drug and isobologram analyses against adult Schistosoma mansoni was also performed, and subsequently applied against other parasitic models (Giardia duodenalis and Haemonchus contortus) to assess the specificity of such effects. Subsequently, the drug combinations were assessed against Schistosoma mansoni in vivo. To further assess the suitability of combinatorial drug applications, an economic model was developed to project the cost-efficacy of praziquantel-triclabendazole drug combinations in a global focus. It was concluded that triclabendazole and its metabolites possessed good efficacy against immature schistosomula, albeit weak efficacy against adult Schistosoma mansoni. Upon combination with praziquantel, however, a strong synergistic effect against adult worms were observed in vitro. Praziquantel and triclabendazole were also shown to possess unique and independent ovicidal modes of action that can be of clinical significance. More importantly, in vivo drug trials concluded that the combinations exerted additive effects against Schistosoma mansoni harbored in mice. Economic modeling and cost-effectiveness analyses further demonstrated the feasibility of this drug combination, and may represent a new line of treatment against mansonial schistosomiasis
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Avaliação dos Efeitos Antineoplásicos da Zebularina em Linhagens Pediátricas de Leucemia Linfoide Aguda. / Evaluation of Antineoplastic Effects of Zebularine on Childhood Acute Lymphoblastic Leukemia Cell Lines.Andrade, Augusto Faria 26 March 2012 (has links)
A leucemia linfóide aguda (LLA) é a neoplasia hematológica mais comum na infância e representa uma doença heterogênea em relação à biologia e ao prognóstico e seu tratamento consiste principalmente em quimioterapia. Apesar dos avanços no tratamento, cerca de 20% dos pacientes apresentam recaída da doença e/ou óbito indicando a necessidade de terapias diferenciadas para esse grupo. Recentemente, drogas epigenéticas como inibidores de DNA metiltransferases (iDNMTs) tem mostrado efeitos anti-neoplásicos promissores para o tratamento de diversos tipos de neoplasias incluindo a LLA. Nos tumores, a hipermetilação gênica é encontrada em vários genes, incluindo genes de reparo do DNA, reguladores do ciclo celular e apoptose. Sendo assim, drogas desmetilantes estão sendo apontadas como promissores agentes para o tratamento do câncer. A Zebularina (ZB) é um iDNMT análogo de citidina que inibe a metilação do DNA. Esta droga tem mostrado resultados animadores para o tratamento de diversas neoplasias, incluindo glioblastoma, leucemia mielóide aguda, câncer de mama, próstata e outros. O objetivo deste trabalho foi avaliar os efeitos do tratamento com a ZB, associada ou não à quimioterápicos, em linhagens celulares pediátricas de LLA, por meio de ensaios funcionais como proliferação celular, capacidade clonogênica, apoptose e ciclo celular. Além disso, foi analisada a capacidade desmetilante da droga e a expressão dos genes DNMT1, DNMT3a e DNMT3b após o tratamento com a ZB. A ZB inibiu a proliferação celular de maneira dose e tempo-dependente e agiu sinergicamente quando combinada com o MTX em ambas as linhagens. Ela também diminuiu a capacidade clonogênica e aumentou a taxa de apoptose nas duas linhagens estudadas. Além disso, o tratamento com ZB causou uma parada na fase S do ciclo celular na linhagem ReH. A ZB foi capaz de desmetilar parcialmente o gene AhR e reduzir a expressão dos genes DNMT1, DNMT3a e DNMT3b. Todos os dados encontrados no presente trabalho sugerem que as drogas desmetilantes podem ser interessantes agentes para o tratamento da LLA pediátrica. / Acute lymphoblastic leukemia (ALL) is the most common hematologic malignancy in childhood and represents a heterogeneous disease regarding its biology and prognosis. Its treatment consists mainly of chemotherapy. Despite advances in treatment, about 20% of patients experience disease recurrence and/or death indicating the need for differentiated therapies for this group. Recently, epigenetic drugs such as DNA methyltransferases inhibitors (iDNMTs) has shown antineoplastic and promising results for several types of tumors including ALL. Gene hypermethylation is found in several genes in tumors cells, including genes responsible for DNA repair, cell cycle and apoptosis regulators. Therefore, demethylating agents may be promising agents for cancer treatment. Zebularine (ZB) an iDNMT is a cytidine analogue that inhibits DNA methylation. This drug has shown promising results for the treatment of many cancers, including glioblastoma, acute myeloid leukemia, breast and prostate cancer and others. The aim of this study was to evaluate the effects of ZB treatment, associated or not with chemotherapeutic agents, in childhood ALL cell lines through functional tests such as cell proliferation, clonogenic capacity, apoptosis and cell cycle. In addition, we examined the demethylating ability of ZB and the expression of DNMT1, DNMT3a and DNMT3b genes after treatment with this agent. ZB inhibited cell proliferation in a dose- and time-dependent manner and showed synergistic effects when combined with MTX in both cell lines. ZB treatment also reduced clonogenic capacity and increased the number of apoptotic cells in both cell lines studied. Furthermore, treatment with ZB caused an S phase cell cycle arrest in ReH cell line. ZB was able to partially demethylate AhR gene and reduce the expression of genes DNMT1, DNMT3a and DNMT3b. These results suggest that demethylating drugs may be interesting agents for the treatment of childhood ALL.
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A Systems Chemical Biology Approach for Dissecting Differential Molecular Mechanisms of Action of Clinical Kinase Inhibitors in Lung CancerJunqueira Sumi, Natalia 05 June 2018 (has links)
Lung cancer is the second most common cancer type and is associated with high mortality rates. The survival rate for lung cancer patients has increased slowly in the last decade mainly as the result of the development of novel targeted and immune therapies. However, non-small cell lung cancer patients lacking known or actionable driver mutations and small cell lung cancer patients with recurrent disease are still in urgent need of new therapies. Drug repurposing is an efficient way to identify new therapies since it uses clinically relevant small molecule drugs. Determination of off-targets of small molecules is a novel approach towards drug repurposing as unintended targets can play important roles for a new clinical application. Here we apply functional proteomics and systems pharmacology approaches to determine target profiles and differential mechanisms of action, independent of the intended targets, of small molecules with similar chemical structures. Using chemical proteomics, we elucidated the differential target profiles of two clinical CDK4/6 inhibitors: palbociclib and ribociclib. We observed that palbociclib, but not ribociclib, is a dual protein and lipid kinase inhibitor that in addition to the intended cell cycle pathway modulates the PI3K/AKT and autophagy pathways. Furthermore, we investigated the off-targets of two MET/VEGFR inhibitors, foretinib and cabozantinib. Foretinib, but not cabozantinib, was found to reduce cell viability and induce cell cycle arrest and apoptosis in lung cancer cell lines. Using a systems pharmacology approach, which included chemical proteomics, phosphoproteomics and RNA-Seq, integrated data analysis and subsequent functional validation revealed a complex polypharmacology mechanism of action of foretinib, which involves the simultaneous inhibition of MEK, AURKB and FER protein kinases. Because AURKB is an important protein kinase for the proliferation of MYC-amplified small cell lung cancer cells, we were able to design a drug combination of foretinib with barasertib, a much more potent AURKB inhibitor, that enhanced specifically the cell death of MYC-amplified small cell lung cancer cells. In summary, we show that small structural changes of closely related clinical drugs can result in pronounced differences in their target profiles and anticancer activities through differential polypharmacology mechanisms and that an integrated systems pharmacology approach can identify new repurposing opportunities for these drugs in cancers with high unmet medical need.
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Avaliação dos Efeitos Antineoplásicos da Zebularina em Linhagens Pediátricas de Leucemia Linfoide Aguda. / Evaluation of Antineoplastic Effects of Zebularine on Childhood Acute Lymphoblastic Leukemia Cell Lines.Augusto Faria Andrade 26 March 2012 (has links)
A leucemia linfóide aguda (LLA) é a neoplasia hematológica mais comum na infância e representa uma doença heterogênea em relação à biologia e ao prognóstico e seu tratamento consiste principalmente em quimioterapia. Apesar dos avanços no tratamento, cerca de 20% dos pacientes apresentam recaída da doença e/ou óbito indicando a necessidade de terapias diferenciadas para esse grupo. Recentemente, drogas epigenéticas como inibidores de DNA metiltransferases (iDNMTs) tem mostrado efeitos anti-neoplásicos promissores para o tratamento de diversos tipos de neoplasias incluindo a LLA. Nos tumores, a hipermetilação gênica é encontrada em vários genes, incluindo genes de reparo do DNA, reguladores do ciclo celular e apoptose. Sendo assim, drogas desmetilantes estão sendo apontadas como promissores agentes para o tratamento do câncer. A Zebularina (ZB) é um iDNMT análogo de citidina que inibe a metilação do DNA. Esta droga tem mostrado resultados animadores para o tratamento de diversas neoplasias, incluindo glioblastoma, leucemia mielóide aguda, câncer de mama, próstata e outros. O objetivo deste trabalho foi avaliar os efeitos do tratamento com a ZB, associada ou não à quimioterápicos, em linhagens celulares pediátricas de LLA, por meio de ensaios funcionais como proliferação celular, capacidade clonogênica, apoptose e ciclo celular. Além disso, foi analisada a capacidade desmetilante da droga e a expressão dos genes DNMT1, DNMT3a e DNMT3b após o tratamento com a ZB. A ZB inibiu a proliferação celular de maneira dose e tempo-dependente e agiu sinergicamente quando combinada com o MTX em ambas as linhagens. Ela também diminuiu a capacidade clonogênica e aumentou a taxa de apoptose nas duas linhagens estudadas. Além disso, o tratamento com ZB causou uma parada na fase S do ciclo celular na linhagem ReH. A ZB foi capaz de desmetilar parcialmente o gene AhR e reduzir a expressão dos genes DNMT1, DNMT3a e DNMT3b. Todos os dados encontrados no presente trabalho sugerem que as drogas desmetilantes podem ser interessantes agentes para o tratamento da LLA pediátrica. / Acute lymphoblastic leukemia (ALL) is the most common hematologic malignancy in childhood and represents a heterogeneous disease regarding its biology and prognosis. Its treatment consists mainly of chemotherapy. Despite advances in treatment, about 20% of patients experience disease recurrence and/or death indicating the need for differentiated therapies for this group. Recently, epigenetic drugs such as DNA methyltransferases inhibitors (iDNMTs) has shown antineoplastic and promising results for several types of tumors including ALL. Gene hypermethylation is found in several genes in tumors cells, including genes responsible for DNA repair, cell cycle and apoptosis regulators. Therefore, demethylating agents may be promising agents for cancer treatment. Zebularine (ZB) an iDNMT is a cytidine analogue that inhibits DNA methylation. This drug has shown promising results for the treatment of many cancers, including glioblastoma, acute myeloid leukemia, breast and prostate cancer and others. The aim of this study was to evaluate the effects of ZB treatment, associated or not with chemotherapeutic agents, in childhood ALL cell lines through functional tests such as cell proliferation, clonogenic capacity, apoptosis and cell cycle. In addition, we examined the demethylating ability of ZB and the expression of DNMT1, DNMT3a and DNMT3b genes after treatment with this agent. ZB inhibited cell proliferation in a dose- and time-dependent manner and showed synergistic effects when combined with MTX in both cell lines. ZB treatment also reduced clonogenic capacity and increased the number of apoptotic cells in both cell lines studied. Furthermore, treatment with ZB caused an S phase cell cycle arrest in ReH cell line. ZB was able to partially demethylate AhR gene and reduce the expression of genes DNMT1, DNMT3a and DNMT3b. These results suggest that demethylating drugs may be interesting agents for the treatment of childhood ALL.
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Predicting safe drug combinations with Graph Neural Networks (GNN)Amanzadi, Amirhossein January 2021 (has links)
Many people - especially during their elderly - consume multiple drugs for the treatment of complex or co-existing diseases. Identifying side effects caused by polypharmacy is crucial for reducing mortality and morbidity of the patients which will lead to improvement in their quality of life. Since there is immense space for possible drug combinations, it is infeasible to examine them entirely in the lab. In silico models can offer a convenient solution, however, due to the lack of a sufficient amount of homogenous data it is difficult to develop both reliable and scalable models in its ability to accurately predict Polypharmacy Side Effect. Recent advancement in the field of representational learning has utilized the power of graph networks to harmonize information from the heterogeneous biological databases and interactomes. This thesis takes advantage of those techniques and incorporates them with the state-of-the-art Graph Neural Network algorithms to implement a Deep learning pipeline capable of predicting the Adverse Drug Reaction of any given paired drug combinations.
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MODELING ANTI-CANCER DRUG RESISTANCE USING TUMOR SPHEROIDSShahi Thakuri, Pradip January 2019 (has links)
No description available.
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DISCOVERY OF NEW ANTIMICROBIAL OPTIONS AND EVALUATION OF AMINOGLYCOSIDE RESISTANCE ENZYME-ASSOCIATED RESISTANCE EPIDEMICHolbrook, Selina Y. L. 01 January 2018 (has links)
The extensive and sometimes incorrect and noncompliant use of various types of antimicrobial agents has accelerated the development of antimicrobial resistance (AMR). In fact, AMR has become one of the greatest global threat to human health in this era. The broad-spectrum antibiotics aminoglycosides (AGs) display excellent potency against most Gram-negative bacteria, mycobacteria, and some Gram-positive bacteria, such as Staphylococcus aureus. The AG antibiotics amikacin, gentamicin, kanamycin, and tobramycin are still commonly prescribed in the U.S.A. for the treatment of serious infections. Unfortunately, bacteria evolve to acquire resistance to AGs via four different mechanisms: i) changing in membrane permeability to resist drugs from entering, ii) upregulating efflux pumps for active removal of intracellular AGs, iii) modifying the antimicrobial target(s) to prevent drugs binding to their targets, and iv) acquiring resistance enzymes to chemically inactivate the compounds. Amongst all, the acquisition of resistance enzymes, AG-modifying enzymes (AMEs), is the most common resistance mechanism identified. Depending on the chemistry each enzyme catalyzes, AMEs can be further divided into AG N-acetyltransferases (AACs), AG O-phosphotransferases (APHs), and AG O-nucleotidyltransferases.
To overcome AME-related resistance, we need to better understand these resistance enzymes and further seek ways to either escape or inhibit their actions. In this dissertation, I summarized my efforts to characterize the AAC(6') domain and its mutant enzymes from a bifunctional AME, AAC(6')-Ie/APH(2")-Ia as well as another common AME, APH(3')-IIa. I also explained my attempt to inhibit the action of various AAC enzymes using metal salts. In an effort to explore the current resistance epidemic, I evaluated the resistance against carbapenem and AG antibiotics and the correlation between the resistance profiles and the AME genes in a collection of 122 Pseudomonas aeruginosa clinical isolates obtained from the University of Kentucky Hospital System. Besides tackling the resistance mechanisms in bacteria, I have also attempted to explore a new antifungal option by repurposing an existing antipsychotic drug, bromperidol, and a panel of its derivatives into a combination therapy with the azole antifungals against a variety of pathogenic yeasts and filamentous fungi.
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Ocorrência e suscetibilidade in vitro a terbinafina, ciclopirox, cetoconazol e itraconazol, com ênfase na combinação entre as drogas antifúngicas de agentes de onicomicose no estado do Espírito SantoHoffmann, Adrielle 10 August 2011 (has links)
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Previous issue date: 2011-08-10 / As onicomicoses, infecções fúngicas de unhas, são causadas por fungos filamentosos dermatófitos e não-dermatófitos e leveduras e representam as micoses superficiais mais difíceis de serem diagnosticadas e tratadas. O tratamento é através do uso tópico e/ou oral com drogas antifúngicas e pode ainda envolver a remoção da unha. O uso de agentes tópicos concomitante à terapia sistêmica leva à melhores resultados clínicos e micológicos. A eficácia da associação medicamentosa pode estar associada à ação complementar entre as drogas, envolvendo diferentes níveis de penetração ungueal e, dependendo dos antifúngicos, de diferentes alvos de ação na célula fúngica. O objetivo do presente estudo consistiu em estabelecer a ocorrência de fungos filamentosos na etiologia das onicomicoses e a suscetibilidade in vitro destes às drogas terbinafina, ciclopirox olamina, cetoconazol e itraconazol, conforme o documento M38-A2 (2008) do CLSI. Foi tambem avaliada a combinação entre estas drogas antifúngicas através do cálculo do índice fracionário de concentração inibitória (IFCI). Nossos resultados demonstraram que prevalência das onicomicoses, no período de janeiro de 2009 a abril de 2011, em Vitória, ES, foi de 50% dentre as dermatomicoses. A maioria dos isolados (77%) foi obtido de pacientes do sexo feminino e o local de maior acometimento foram as unhas dos pés para ambos os sexos. As unhas das mãos foram mais acometidas por leveduras e as unhas dos pés, por fungos filamentosos. Em geral, os gêneros de fungos filamentosos mais predominantes na etiologia das onicomicoses foram Trichophyton spp (21,7%), Fusarium spp. (11,2%) e Scytalidium spp.(8,4%). Para fungos filamentosos, os testes de suscetibilidade in vitro mostraram que isolados de dermatófitos foram mais sensíveis que isolados do grupo não-dermatófitos. Entre os nãodermatófitos, Fusarium spp. foi menos inibido que Scytalidium spp., que por sua vez, foi menos inibido que o dermatófito Trichophyton spp. Dentre as combinações testadas não houve nenhum efeito antagônico e,, com exceção daquela entre itraconazol e cetoconazol, as demais apresentaram efeito sinérgico sobre algum isolado. A combinação entre drogas apresentou maiores índices de sinergismo para o gênero Scytalidium spp. O melhor resultado para este gênero foi também obtido pela combinação itraconazol e terbinafina / The onychomycosis, fungal nail infections, are caused by filamentous fungi dermatophytes and non-dermatophytes and yeasts and represent the most difficult superficial mycosis to be diagnosed and treated. Treatment involves use of topical and/or oral antifungal drugs, as well as removal of the nail. The use of topical agents concomitant to systemic therapy leads to better clinical and mycological results. The efficacy of combination therapy may be associated with a complementary action between the drugs, involving different levels of nail penetration and, depending on the antifungal, different targets of action in the fungal cell. The purpose of this study was to establish the occurrence of filamentous fungi in the etiology of onychomycosis and in vitro susceptibility to the drugs terbinafine, ciclopirox olamine, ketoconazole and itraconazole, according to document M38-A2 (2008) CLSI. It was also evaluated the combination among these antifungal drugs by calculating the fractional inhibitory concentration index (FICI). Our results showed that the prevalence of onychomycosis in the period from January 2009 to April 2011, in Vitoria, ES, Brazil, was 50% among the dermatomycosis cases. Most of the isolates (77%) were obtained from female patients and toenails were the local with greater involvement for both sexes. The fingernails were more affected by yeast and toenails, by filamentous fungi. In general, the genera of filamentous fungi more prevalent in the etiology of onychomycosis was Trichophyton spp (21.7%), Fusarium spp. (11.2%) and Scytalidium spp. (8.4%). For filamentous fungi, the in vitro susceptibility testing showed that dermatophytes were more susceptible than non-dermatophytes isolates. Among non-dermatophytes, Fusarium spp. was less inhibited than Scytalidium spp., which in turn, was less inhibited than the dermatophyte Trichophyton spp. Among the combinations tested, there was no antagonistic effect and,, with exception of ketoconazole and itraconazole, those ones showed synergistic effect for isolates. The best results were presented for combinations involving itraconazole and terbinafine. The drug combination with greater synergistic effect was observed for genus Scytalidium spp. being that the combination itraconazole and terbinafine presented also the best results for this genus
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Enhancing Root Caries Lesion Prevention By Combining Two American Dental Association-Recommended Preventive AgentsAlmudahi, Abdulellah January 2022 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Purpose: This in vitro study aims to analyze the effect of combining two ADA-recommended professionally applied 1:1 Chlorhexidine/Thymol varnish ((Cervitec Plus)) and professionally prescribed 5,000 ppm fluoride toothpaste ((PreviDent 5000 Plus)) on reducing lesion depth and increasing mineral content Materials & Methods: Forty-eight dentin specimens were randomly distributed into four treatment groups (n=12 per treatment). Biofilms of Streptococcus mutans and Candida albicans were created on the polished surfaces of bovine root dentin specimens (n=12 per treatment). 1:1 Chlorhexidine/Thymol varnish was applied once then the tested 5,000 ppm fluoride toothpaste was applied for 120 seconds twice daily over the course of 2 days. Tested groups were: (1) 1:1 Chlorhexidine/Thymol varnish ((Cervitec Plus)) (C/T). (2) 5,000 ppm F toothpaste ((PreviDent 5000 Plus)) (F). (3) Combination of 1:1 Chlorhexidine/Thymol varnish ((Cervitec Plus)) & 5000 ppm F toothpaste ((PreviDent 5000 Plus)) (C/T+F). (4) Deionized water (DIW) as control group. Biofilms were analyzed for biofilm dry weight. Dentin specimens were analyzed using transversal microradiography (TMR) for mineral content change and lesion depth. PH data was analyzed using two-way ANOVA. Total biofilm dry weight data was analyzed using one-way ANOVA. Integrated mineral loss and lesion depth data was analyzed using two-way ANOVA All pair-wise comparisons from ANOVA analysis were made using Fisher’s Protected Least Significant Differences to control the overall significance level at 5%. Results: Treatment with (C/T+F) resulted in higher mean pH values compared to the control group (DIW) and (F) group. The average pH values of group (C/T) were not statistically different than group (C/T+F). the biomass of the combined S. mutans & C. albicans biofilm among all the groups were not significantly different. (DIW) presented significantly deeper lesions for both surfaces (sound &demineralized) when compared to (F) (P=0.0118), (C/T) (P=0.0002), and (C/T+F) (P<.0001). The sound surfaces for the specimens for group (C/T) and Group (F) showed superficial lesion depth. However, the sound surfaces of specimens treated with (C/T+F) showed the most superficial depth. Due to mineral gain, the demineralized surfaces of the specimens of both (C/T) & (C/T+F) showed a decrease in the lesion depth. Conclusion: Within the limitations of our study. The combination of 5,000 ppm fluoride toothpaste and CHX/Thymol had no significant effect on mineral content. However, the combination had a considerable effect on lesion depth reduction.
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Strategic pre-clinical development of Riminophenazines as resistance circumventing anticancer agentsKoot, Dwayne Jonathan 26 April 2013 (has links)
Cancer is responsible for upward of 13% of human deaths. Contemporary chemotherapy of disseminated cancer is often thwarted by dose limiting systemic toxicity and by multi-drug resistance (MDR). Riminophenazines are a novel class of potential anticancer agents that possess a potent multi-mechanistic antineoplastic action. Apart from their broad action against intrinsic, non-classical resistance, Riminophenazines inhibit the action of Pgp and hypothetically all ABC transporters demonstrating their great utility against classical MDR. Considering that combination chemotherapy is the norm, the vision directing R&D efforts was that Riminophenazines could be used with benefit within many standard chemotherapeutic regimes. The strategic intent of this project was to attain improved therapeutic benefit for patients through gains in both pharmaco dynamic and pharmacokinetic specificity for cancer cells over what is currently available. Tactically, this was driven through the use of synergistic Fixed-Ratio Drug Combinations (FRDC) encapsulated within tumour-targeting Nanoparticulate Drug Delivery Systems (NDDS). Long-term aims of this R&D project were to: 1) Screen FRDC of clofazimine (B663) and the lead derivative (B4125) with etoposide, paclitaxel and vinblastine for synergistic drug interactions in vitro. 2) Design, assemble and characterize a novel nanoparticulate, synergistic, anticancer co-formulation. 3) Evaluate the in vivo safety and efficacy of the developed product/s in accordance with international regulatory guidelines. Using the median effect and combination index equations, impressive in vitro synergistic drug interactions (CI<1) were shown for various FRDC of the three standard chemotherapeutics tested (etoposide, paclitaxel and vinblastine) in combination with either B663 or B4125 against MDR neoplastic cell cultures. Considering in vitro results and with the view to advance quickly to clinical studies, the already approved clofazimine (B663) was elected as the combination partner for paclitaxel (PTX). Considering the potency and wide action of PTX, a novel coformulation (designed to circumvent drug resistance) has the potential to greatly impact upon virtually all cancer types, particularly if selectively delivered through innovative delivery systems and loco-regional administration. A passively tumour targeting, micellular NDDS system called Riminocelles™ that encapsulates a synergistic FRDC of B663 and PTX has been designed, assembled using thin film hydration methods and characterized in terms of drug loading, particle size, zeta potential, CMC and drug retention under sink conditions. An acute toxicity and a GLP repeat dose toxicity study confirmed Riminocelles to be well tolerated and safe at clinically relevant dosages whilst Taxol® (QDx7) produced statistically significant (P<0.05) weight loss within 14 days. The same study demonstrated statistically significant (P<0.05) tumour growth delays superior to that of Taxol at an equivalent PTX dosage of 10 mg/kg. Importantly, all components (amphiphiles and drugs) used in assembly of Riminocelles are already individually approved for medicinal use - this promotes accelerated development towards advanced clinical trials and successful registration. Although these results are very promising (outperforming Taxol), this system was however found in a pharmacokinetic study to suffer from in vivo thermodynamic instability due to the high concentration (abundance) of albumin present in plasma. For this reason, in vivo longevity within circulation, permitting passive tumour accumulation was not fully realized. A second NDDS called the RiminoPLUS™ imaging system was additionally developed. This lipopolymeric nanoemulsion system has successfully entrapped Lipiodol® Ultra fluid (an oil based contrast agent) within the hydrophobic core of a monodisperse particle population with a size of roughly 100 nm and a stability of one week. This formulation is therefore thought capable of CT imaging of tumour tissue and drug targeting after either intravenous or loco-regional injection. In vivo proof of the imaging concept is warranted. The results of this study serve to highlight the great potential of in vitro optimized synergistic FRDC against drug resistant cancers. Lipopolymeric micelles are an effective way to formulate multiple hydrophobic drugs for intravenous administration and present a means by which cancer can be readily targeted; provided that the delivery system possess the prerequisite in vivo stability and surface attributes. Further experiments exploring synergistic drug and biological combinations as well as “intelligent” NDDS actively guided through specific molecular recognition are called for. / Thesis (PhD)--University of Pretoria, 2012. / Pharmacology / unrestricted
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