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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Studies of PLGA Nanoparticles for Pharmaceutical Applications

Sun, Yanqi 08 1900 (has links)
PLGA have already been successfully applied for controlled drug delivery systems by the pharmaceutical industry due to its biocompatibility, biodegradability and ease of processing. It has recently further been developed and formulated into a form of nanoparticle. The single emulsion evaporation method was used to prepare nanoparticles in this study. By varying different parameters such as the concentration of regents, the type of surfactant and emulsion method, different particle sizes and size distribution of PLGA nanoparticles could be obtained. The stability of PLGA nanoparticles was further investigated by assessing their thermal property over a certain period of time using DSC. The decrease of Tg confirmed the hydration and degradation of PLGA polymers and nanoparticles. The changes of surface morphology showed that the nanoparticles were in spherical shape and maintained smooth surface before the storage, whereas they started to lose their original shapes as well as agglomerate to each other after 2-week storage. These results suggested that there was an erosion and degradation of PLGA nanoparticles during storage. Ibuprofen-loaded PLGA nanoparticles have been successfully prepared by o/w single emulsion evaporation method. During the stability study, a faster degradation rate compared to non-loaded PLGA nanoparticles was exhibited, showing that Ibuprofen increased the degradation rate of PLGA nanoparticles. According to the results of drug releasing study, PLGA nanoparticles exhibiting a slower drug release rate than pure drug which proved that drug-nanoparticule system could effectively increase the stability of drugs. PLGA polymer is a potential material for drug delivery system.
82

The use of solubility parameters to predict the behaviour of a co-crystalline drug dispersed in a polymeric vehicle : approaches to the prediction of the interactions of co-crystals and their components with hypromellose acetate succinate and the characterization of that interaction using crystallographic, microscopic, thermal, and vibrational analysis

Isreb, Abdullah January 2012 (has links)
Dispersing co-crystals in a polymeric carrier may improve their physicochemical properties such as dissolution rate and solubility. Additionally co-crystal stability may be enhanced. However, such dispersions have been little investigated to date. This study focuses on the feasibility of dispersing co-crystals in a polymeric carrier and theoretical calculations to predict their stability. Acetone/chloroform, ethanol/water, and acetonitrile were used to load and grow co-crystals in a HPMCAS film. Caffeine-malonic acid and ibuprofennicotinamide co-crystals were prepared using solvent evaporation method. The interactions between each of the co-crystals components and their mixtures with the polymer were studied. A solvent evaporation approach was used to incorporate each compound, a mixture, and co-crystals into HPMCAS films. Differential scanning calorimetry data revealed a higher affinity of the polymer to acidic compounds than their basic counterparts as noticed by the depression of the glass transition temperature (Tg). Moreover, the same drug loading produced films with different Tgs when different solvents were used. Solubility parameter values (SP) of the solvents were employed to predict that effect on the depression of polymer Tg with relative success. SP values were more successful in predicting the preferential affinity of two acidic compounds to interact with the polymer. This was confirmed using binary mixtures of naproxen, flurbiprofen, malonic acid, and ibuprofen. On the other hand, dispersing basic compounds such as caffeine or nicotinamide with malonic acid in HPMCAS film revealed the growth of co-crystals. A dissolution study showed that the average release of caffeine from films containing caffeine-malonic acid was not significantly different to that of films containing similar caffeine concentration. The stability of the caffeine-malonic acid co-crystals in HPMC-AS was prolonged to 8 weeks at 95% relative humidity and 45°C. The theory developed in this project, that an acidic drug with a SP value closer to the polymer will dominate the interaction process and prevent the majority of the other material from interacting with the polymer, may have utility in designing co-crystal systems in polymeric vehicles
83

Preparation and stability of organic nanocrystals : experimental and molecular simulation studies

Khan, Shahzeb January 2012 (has links)
A major challenge affecting the likelihood of a new drug reaching the market is poor oral bioavailability derived from low aqueous solubility. Nanocrystals are rapidly becoming a platform technology to address poor solubility issues, although several challenges including stabilisation and control of particle size distribution for nanosuspensions still need to be addressed. The aim of this study was to revisit the simplest approach of re-precipitation and to identify the critical parameters, including the effect of different stabilisers as well as process conditions. We utilised a combined approach of both experiments and molecular modelling and simulation, not only to determine the optimum parameters but also to gain mechanistic insight. The experimental studies utilised three rather distinct, relatively insoluble drugs, the hypoglycaemic glibenclamide, the anti-inflammatory ibuprofen, and the anti-malarial artemisinin. The choice of crystal growth inhibitors/stabilizers was found to be critical and specific for each drug. The effect of the process variables, temperature, stirring rate, and the solute solution infusion rate into the anti-solvent, was rationalized in terms of how these factors influence the local supersaturation attained at the earliest stages of precipitation. Coarse grained simulation of antisolvent crystallisation confirmed the accepted two step mechanism of nucleation at high supersaturation which involves aggregation of solute particles followed by nucleation. Recovery of nanocrystals from nanosuspensions is also a technical challenge. A novel approach involving the use of carrier particles to recovery the nanocrystals was developed and shown to be able to recover more than 90% of the drug nanocrystals. The phase stability of nanocrystals along with bulk crystals for the model compound glycine was explored using molecular dynamics simulation. The simulations were consistent with experimental data, a highlight being the β phase transforming to the δ phase at temperature >400K and 20kbar respectively, as expected. Nanocrystals of α, β and γ glycine, however did not show any phase transformation at high temperature. In summary the study demonstrates that standard crystallization technology is effective in producing nanocrystals with the primary challenge being physico-chemical (rather than mechanical), involving the identification of molecule-specific crystal growth inhibitors and/or stabilizers. The developed nanocrystal recovery method should enable the production of nanocrystals-based solid dosage forms. The molecular simulation studies reveal that crystal-crystal phase transformations can be predicted for hydrogen-bonded systems.
84

Design and evaluation of chitosan and N-trimethyl chitosan chloride microspheres for intestinal drug delivery / Johannes Petrus Venter

Venter, Johannes Petrus January 2005 (has links)
The absorption enhancing ability of chitosan, a linear polysaccharide, is mediated by protonated amino groups on the C-2 position of the molecules that induce interaction with the anionic sites on the cell membranes to subsequently alter tight junction integrity. In neutral and basic environments, such as those found in the small and large intestines, most chitosan molecules will lose their charge and precipitate from solution rendering it ineffective as an absorption enhancer. To increase the solubility of this polymer, methylation of the amino groups on the C- 2 position was proposed. A partially quaternised and water soluble derivative of chitosan, N-trimethyl chitosan chloride (TMC), which exhibits superior solubility in a basic environment compared with other chitosan salts was synthesised and included in a chitosan microbead solid drug delivery system. Two TMC derivatives were synthesised by reductive methylation from high and medium molecular weight Chitoclear™ chitosan respectively. The degree of quaternisation calculated from the 1H-NMR spectra for the medium molecular weight TMC (TMC-M) and the high molecular weight TMC (TMC-H) polymers were 74.7 % and 48.5 % respectively. The mean molecular weights of the synthesised TMC-M and TMC-H polymers were 64 100 g/mole and 233 700 g/mole respectively. The effect of different concentrations TMC-M and TMC-H on chitosan microbeads was studied with results obtained from scanning electron microscopy (SEM), TMC loading capacity and microbead swelling behaviour. After selection of the most suitable TMC concentration, the effect of varying concentration (0.1, 0.2 and 0.5 %) additives on TMC and ibuprofen release was studied. Commonly used modified cellulose gum (Ac-di-sol®(ADS)), sodium starch glycolate (Explotab®(EXP)) and ascorbic acid (AA) were added as disintegrants to different microbead formulations to promote release of both the ibuprofen as model drug and TMC from the beads. It was noticed that the loading (% drug loading capacity) of TMC-M was much lower than that obtained with TMC-H while the inclusion of different additives in varying concentrations did not seem to have a profound influence on the loading of either TMC-M or TMC-H. It was further noticed from the fit factors (f1 and f2) for dissolution profiles of eighteen chitosan microbead variations that the formulation containing TMC-H and 0.5% (w/v) ascorbic acid was the only formulation with a significantly higher ibuprofen and TMC-H release profile compared to all other formulations tested. The chitosan microbead formulation containing 2%(w/v) TMC-H and 0.5 % (w/v) ascorbic acid (H-AA-0.5) was used for in vitro absorption studies through rat intestine in Sweetana-Grass diffusion chambers. Chitosan containing TMC-H (no ascorbic acid) (CHIT-H) only and a plain chitosan microbead (CHIT) formulation was used as control formulations during the in vitro studies. Although the H-AA-0.5 formulation exhibited the highest transport rate for ibuprofen, the mean rate of transport (P app) obtained from the two formulations containing TMCH (CHIT-H and H-AA-0.5) showed no significant difference in the transport rate of ibuprofen. Compared to the CHlT formulation as control, both formulations containing TMC-H exhibited increased ibuprofen transport across in vitro rat jejunum. However, a statistical significant increase in transport was obtained only from the H-AA-0.5 formulation in comparison with the CHlT formulation. It can be concluded that the combination of high molecular weight TMC with a low degree of quaternisation and ascorbic acid (0.5% w/v) in a chitosan microbead lead to a statistical significant increase in the in vitro transport rate of ibuprofen through rat jejunum. / Thesis (Ph.D. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2006.
85

Design and evaluation of chitosan and N-trimethyl chitosan chloride microspheres for intestinal drug delivery / Johannes Petrus Venter

Venter, Johannes Petrus January 2005 (has links)
The absorption enhancing ability of chitosan, a linear polysaccharide, is mediated by protonated amino groups on the C-2 position of the molecules that induce interaction with the anionic sites on the cell membranes to subsequently alter tight junction integrity. In neutral and basic environments, such as those found in the small and large intestines, most chitosan molecules will lose their charge and precipitate from solution rendering it ineffective as an absorption enhancer. To increase the solubility of this polymer, methylation of the amino groups on the C- 2 position was proposed. A partially quaternised and water soluble derivative of chitosan, N-trimethyl chitosan chloride (TMC), which exhibits superior solubility in a basic environment compared with other chitosan salts was synthesised and included in a chitosan microbead solid drug delivery system. Two TMC derivatives were synthesised by reductive methylation from high and medium molecular weight Chitoclear™ chitosan respectively. The degree of quaternisation calculated from the 1H-NMR spectra for the medium molecular weight TMC (TMC-M) and the high molecular weight TMC (TMC-H) polymers were 74.7 % and 48.5 % respectively. The mean molecular weights of the synthesised TMC-M and TMC-H polymers were 64 100 g/mole and 233 700 g/mole respectively. The effect of different concentrations TMC-M and TMC-H on chitosan microbeads was studied with results obtained from scanning electron microscopy (SEM), TMC loading capacity and microbead swelling behaviour. After selection of the most suitable TMC concentration, the effect of varying concentration (0.1, 0.2 and 0.5 %) additives on TMC and ibuprofen release was studied. Commonly used modified cellulose gum (Ac-di-sol®(ADS)), sodium starch glycolate (Explotab®(EXP)) and ascorbic acid (AA) were added as disintegrants to different microbead formulations to promote release of both the ibuprofen as model drug and TMC from the beads. It was noticed that the loading (% drug loading capacity) of TMC-M was much lower than that obtained with TMC-H while the inclusion of different additives in varying concentrations did not seem to have a profound influence on the loading of either TMC-M or TMC-H. It was further noticed from the fit factors (f1 and f2) for dissolution profiles of eighteen chitosan microbead variations that the formulation containing TMC-H and 0.5% (w/v) ascorbic acid was the only formulation with a significantly higher ibuprofen and TMC-H release profile compared to all other formulations tested. The chitosan microbead formulation containing 2%(w/v) TMC-H and 0.5 % (w/v) ascorbic acid (H-AA-0.5) was used for in vitro absorption studies through rat intestine in Sweetana-Grass diffusion chambers. Chitosan containing TMC-H (no ascorbic acid) (CHIT-H) only and a plain chitosan microbead (CHIT) formulation was used as control formulations during the in vitro studies. Although the H-AA-0.5 formulation exhibited the highest transport rate for ibuprofen, the mean rate of transport (P app) obtained from the two formulations containing TMCH (CHIT-H and H-AA-0.5) showed no significant difference in the transport rate of ibuprofen. Compared to the CHlT formulation as control, both formulations containing TMC-H exhibited increased ibuprofen transport across in vitro rat jejunum. However, a statistical significant increase in transport was obtained only from the H-AA-0.5 formulation in comparison with the CHlT formulation. It can be concluded that the combination of high molecular weight TMC with a low degree of quaternisation and ascorbic acid (0.5% w/v) in a chitosan microbead lead to a statistical significant increase in the in vitro transport rate of ibuprofen through rat jejunum. / Thesis (Ph.D. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2006.
86

Investigation of activated remodelling in the healing of experimental stress fractures and the influence of anti-inflammatory treatments

Lisa Kidd Unknown Date (has links)
Investigation of activated remodelling in the healing of experimental stress fractures and the influence of anti-inflammatory treatments Lisa Jane Kidd Abstract Targeted and focal remodelling are important processes in bone homeostasis and pathology. However, the factors that initiate and direct remodelling to repair microcracks, or respond to excess loading are still poorly understood. The rat ulna-loading (RUL) model has been widely used to examine modelling and remodelling responses to axial cyclic loading. However the model has not yet been fully characterised. Stress fractures are common amongst athletes, dancers and military recruits, but there is almost no information available on the mechanism of healing of these fractures. Although cyclooxygenase-2 (COX-2) is a key mediator of bone resorption and bone formation, very little information is available on the effect of non-steroidal antiinflammatories (NSAIDs) on stress fracture healing. Remodelling may play a role in the pathogenesis of stress fractures, and there is growing interest in the potential use of bisphosphonates to prevent them. Nonetheless, the effect of bisphosphonates on stress fracture healing is not known. PMX53 is a C5a receptor antagonist developed as a novel anti-inflammatory agent. It is effective against inflammatory arthritis, but has not been tested in any fracture models. The aims of this study were to undertake a detailed examination of the histology, histomorphometry and gene expression of the healing and remodelling process initiated by RUL, and to use this model to determine the effects of selective and non-selective NSAIDs, a bisphosphonate and PMX53 on stress fracture healing. To characterise the RUL model, fatigue fractures were created by loading ulnae until displacement was observed to increase by between 4% and 50%. Ulnae were bulk-stained in basic fuchsin and processed for undecalcified histology. For all remaining experiments, loading was stopped when the displacement had increased by 10%. For detailed histology and histomorphometry, ulnae were decalcified, paraffin embedded and stained with toluidine blue, saffranin-O or for tartrate resistant acid phosphatase (TRAP). Ulnae were examined at 1, 2, 4, 6, 8, and 10 weeks after loading. The effects of DFU (a selective COX-2 inhibitor, 2 mg/kg po), ibuprofen (a non-selective NSAID, 30 mg/kg po) and PMX53 (10 mg/kg po) were examined at 2, 4 and 6 weeks after loading. Effects of risedronate (a bisphosphonate) were examined at a high (1.0 mg/kg po) and low dose (0.1 mg/kg po) at 2, 6 and 10 weeks after loading. RUL did not create isolated intracortical microcracks, but curvilinear fatigue fractures that occurred at a standard position in the medial cortex of the distal ulna diaphysis. These stress fractures induced rapid periosteal woven bone formation and direct intracortical remodelling along the fracture line that originated at the periosteum and progressed towards the medullary cavity. Basic multicellular units (BMUs) could be followed through serial sections extending along the fracture line towards the centre of the bone. Quantitative, real-time PCR was performed at 4 hours, 24 hours, 4 days, 7 days and 14 days after fatigue fracture. Following each period, bones were dissected and mRNA was extracted using standard protocols. Gene expression was compared between loaded and unloaded ulnae and to an unloaded control group. Four hours after loading, there was a marked, 220-fold increase (P<0.0001) in expression of Interleukin-6 (IL-6). There were also prominent peak increases in mRNA expression for Osteoprotegerin (OPG), cyclooxygenase-2 (COX-2), and vascular endothelial growth factor (VEGF) (all P<0.0001). At 24 hours there was a peak increase in mRNA expression for IL-11 (73-fold increase, P<0.0001). At 4 days there was a significant increase in mRNA expression for Bcl-2, COX-1, bone morphogenic protein (BMP)-2, insulin-like growth factor (IGF)-1, osteopontin (OPN), and stromal cell derived factor SDF-1. At 7 days there was a significant increase in mRNA expression of Receptor activator of nuclear factor kappa β ligand (RANKL) and OPN. The dramatic, early up-regulation of IL-6 and IL-11 suggests they play a central role in initiating signalling events for stress fracture healing. Treatment with PMX53 did not affect any measures of woven bone formation or stress fracture remodelling. There were no treatment effects of Ibuprofen or DFU on the area of woven bone. DFU treatment resulted in a significant reduction in the area of porosity (resorption) and BMU area along the fracture line at 2 weeks after fracture. Ibuprofen treatment resulted in a significant reduction in length and area of BMUs and new bone formation along the fracture line at 6 weeks (p < 0.05). This is the first report to demonstrate a negative effect on stress fracture healing of both a selective COX-2 inhibitor and a non-selective NSAID. These data confirm the importance of cyclooxygenase in bone resorption and formation during remodelling. Bisphosphonates are potent inhibitors of osteoclastic bone resorption Two, 6 and 10 weeks after loading, measures of resorption and new bone formation were significantly reduced along the fracture line by high dose risedronate treatment, but not by the low dose. Only the porosity along the fracture line 2 weeks after loading was significantly reduced by the low dose risedronate. The low dose more closely resembles the clinical dose used to treat patients. Woven bone formation and consolidation were not affected by the low or high doses of risedronate. In conclusion, fatigue fractures in the rat ulna are highly reproducible, induce exuberant periosteal woven bone formation, and heal by direct remodelling along the fracture line. Remodelling is associated with gene expression for molecules typically associated with bone resorption and formation, angiogenesis and cell signalling. Remodelling of the stress fracture line was adversely affected by treatment with selective and non-selective COX inhibitors, by high dose treatment with risedronate, but not by PMX53, a C5a antagonist.
87

Studies of micellar electrokinetic chromatography as an analytical technique in pharmaceutical analysis : an industrial perspective /

Stubberud, Karin, January 2002 (has links)
Diss. (sammanfattning) Uppsala : Univ., 2002. / Härtill 5 uppsatser.
88

Monitoramento de fármacos em água superficial e efluente de estação de tratamento de esgoto no município de Dracena - SP / Monitoring of drugs in surface water and effluent from a sewage treatment plant in the municipality of Dracena - SP

Ragassi, Bruna 07 May 2018 (has links)
Submitted by BRUNA RAGASSI (bruna_ragassi@hotmail.com) on 2018-06-28T16:17:37Z No. of bitstreams: 1 Bruna Ragassi .pdf: 2101839 bytes, checksum: 9fec82e4090b7e088c646916c780712d (MD5) / Approved for entry into archive by Cristina Alexandra de Godoy null (cristina@adm.feis.unesp.br) on 2018-06-28T17:14:39Z (GMT) No. of bitstreams: 1 ragassi_b_me_ilha.pdf: 2101839 bytes, checksum: 9fec82e4090b7e088c646916c780712d (MD5) / Made available in DSpace on 2018-06-28T17:14:39Z (GMT). No. of bitstreams: 1 ragassi_b_me_ilha.pdf: 2101839 bytes, checksum: 9fec82e4090b7e088c646916c780712d (MD5) Previous issue date: 2018-05-07 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A qualidade da água é um assunto de crescente preocupação, especialmente devido à presença de fármacos que contaminam o ambiente aquático. Muitos compostos têm sido detectados em efluentes de estações de tratamento de esgoto (ETEs) e águas superficiais em todo o mundo. A ocorrência de fármacos no ambiente pode apresentar efeitos adversos aos ecossistemas aquáticos. O objetivo desse estudo foi avaliar a presença e a concentração dos fármacos diclofenaco, ibuprofeno e naproxeno durante março de 2017 a fevereiro de 2018 em 7 pontos de amostragem, sendo 5 pontos no Córrego das Marrecas - SP e 2 pontos na ETE do município de Dracena - SP. Em cada ponto do córrego foi mensurada a concentração de oxigênio dissolvido (OD), pH, temperatura e sólidos totais dissolvidos (SDT) com auxílio de uma Sonda Multiparamétrica Aquaread AP 2000. Para a identificação dos fármacos, as amostras foram preparadas por microextração líquido – líquido dispersiva e analisadas por cromatografia líquida de alta eficiência. Foi realizada uma análise descritiva para avaliação dos resultados de média, desvio padrão e coeficiente de variação dos parâmetros físico-químicos. Uma matriz de correlação foi aplicada para avaliar a interação entre os parâmetros físico-químicos da água e os fármacos dois a dois. Os três fármacos foram detectados em todos os pontos da ETE e do córrego. A maior concentração do diclofenaco (0,458 mg.L-1) foi registrada no ponto de lançamento do efluente da ETE no mês de março. Nesse ponto foi verificada a maior concentração de ibuprofeno (0,120 mg.L-1), porém no mês de maio. O naproxeno apresentou a maior concentração (0,040 mg.L-1) no mês de abril na nascente do Córrego das Marrecas e a jusante da ETE. Os parâmetros que apresentaram uma correlação significativa foram: ibuprofeno x temperatura, quanto maior a temperatura, menor a concentração de ibuprofeno. Oxigênio dissolvido x sólidos totais dissolvidos, quanto maior os STD, menor a concentração de OD. Oxigênio dissolvido x temperatura, quanto maior a temperatura menor o OD. Mudanças e melhorias devem ser realizadas para que a remoção desses compostos seja total, amenizando a transferência dessas substâncias para os ambientes aquáticos e diminuindo seus riscos para a saúde humana e para o meio ambiente. / Water quality is a subject of increasing concern, especially due to the presence of drugs that contaminate the aquatic environment. Many compounds have been detected in effluents from sewage treatment plants (ETEs) and surface water worldwide. The occurrence of drugs in the environment may have adverse effects on aquatic ecosystems. The objective of this study was to evaluate the presence and concentration of the drugs diclofenac, ibuprofen and naproxen during March 2017 to February 2018 in 7 sampling points, 5 points in the Stream of Marrecas - SP and 2 points in the TTE of the municipality of Dracena - SP The concentrations of dissolved oxygen (DO), pH, temperature and total dissolved solids (TDS) were measured at each point of the stream using an Aquaread AP 2000 Multiparameter Probe. For drug identification, the samples were prepared by dispersive liquid-liquid microextraction and analyzed by chromatography high efficiency liquid. A descriptive analysis was performed to evaluate the results of mean, standard deviation and coefficient of variation of physical-chemical parameters. A correlation matrix was applied to evaluate the interaction between the physicochemical parameters of water and drugs two to two. All three drugs were detected at all points of the TEE and the stream. The highest concentration of diclofenac (0.458 mg.L-1) was recorded at the point of launch of the ETE effluent in March. At that point, the highest concentration of ibuprofen (0.120 mg.L-1) was observed, but in May. The naproxen had the highest concentration (0.040 mg.L-1) in April at the source of the Stream of Marrecas and downstream of the TEE. In the TEE it was observed that a greater reduction of diclofenac occurred (97.7% in March), followed by ibuprofen (91.7%) and naproxen (43.5%) both in April. The parameters that presented a significant correlation were: ibuprofen x temperature, the higher the temperature, the lower the concentration of ibuprofen. Dissolved oxygen x total dissolved solids, the higher the STD, the lower the OD concentration. Dissolved oxygen x temperature, the higher the temperature the lower the OD. Changes and improvements should be made to the removal of these compounds, minimizing the transfer of these substances to aquatic environments and reducing their risks to human health and the environment.
89

Análise da potencialidade ergogênica e riscos associados ao uso do antiinflamatório não-esteroidal ibuprofeno em corredores de endurance / Analysis of the ergogenic potential and risks associated with the use of non-steroidal anti-inflammatory ibuprofen in endurance runners

Silva, Eduardo Ramos da January 2009 (has links)
Introdução: Devido ao fato dos antiinflamatórios serem amplamente utilizados no meio atlético, da suposta melhora de desempenho pelo efeito analgésico, independentemente da presença ou não de lesão, e, por fim, em razão dos extensos relatos de efeitos adversos associados a esta classe farmacológica, o objetivo da presente Tese Doutoral foi verificar a potencialidade do antiinflamatório não-esteroidal (AINE) Ibuprofeno em enquadrar-se como doping segundo o Código Mundial Antidoping da Agência Mundial Antidoping (WADA-COI), segundo critérios de ergogenia e risco à saúde em atleta em corrida de duração. Para tanto, foram realizados um estudo observacional e três ensaios clínicos, randomizados e duplo-cego. Materiais e Métodos: No primeiro trabalho (laboratorial), 14 atletas especialistas em provas de longa duração realizaram dois testes progressivos de corrida em esteira rolante com 72 horas de intervalo (modelo cruzado), sendo administrada em cada teste dose única e por via oral de 1,2g de AINE ou Placebo (lactose). Os resultados indicaram que o uso de AINE reduziu a percepção de esforço no segundo limiar ventilatório (p 0,01), todavia com diminuição da velocidade associada (p=0,01) e redução do VO2máx (p=0,04). No segundo estudo, 20 sujeitos (2x10 sujeitos) condicionados e saudáveis, após determinação da velocidade associada ao segundo limiar ventilatório, foram submetidos a um protocolo de tempo limite para exaustão (tlim) em corrida antes e 48h após indução de dano muscular com exercícios concêntricos e excêntricos (em dinamômetro isoscinético) nos grupos musculares do compartimento anterior e posterior da coxa. No segundo teste (pós-dano) um grupo recebeu, em dose única e por via oral, 1,2g de AINE e o outro grupo Placebo. Os resultados indicaram redução significativa do tlim em ambos os grupos (p 0,01), contudo sem atenuação de queda pelo AINE (p=0,55). No terceiro e último experimento, 14 atletas realizaram duas provas simuladas (PS) de 10 km em pista com sete dias de intervalo. Em cada dia os sujeitos receberam tratamento farmacológico idêntico aos estudos anteriores (modelo cruzado) tendo sido monitorados a filtragem glomerular (FG) pela técnica de clearance de 51CrEDTA, assim como o desempenho (tempo total de teste). Em ambas PSs foi observada redução significativa da FG (p 0,01), porém sem diferenciação entre as situações de uso de AINE e Placebo (p=0,235). O desempenho foi impactado negativamente pelo fármaco (p=0,02). Conclusões específicas: em corredores condicionados e atletas, a administração profilática de Ibuprofeno em dose única por via oral possui potencial chance de redução do desempenho por impactar possivelmente a distribuição volêmica ao tecido ativo (efeito associado à redução de hiperemia tecidual e à resposta cronotrópica frente ao exercício). Não restou assegurada sua eficácia analgésica sobre a atenuação do desconforto agudo (gerado pela corrida) ou tardio (gerado por dano prévio) no que tange a relação dor X desempenho. E por fim, a administração de dose única deste Ibuprofeno antes da corrida (nas condições de análise), não potencializa a condição de insuficiência renal aguda gerada pelo próprio exercício. Conclusão geral: O presente modelo experimental indica que o uso do antiinflamatório não-esteroidal Ibuprofeno não apresenta potencialidade de enquadrar-se como doping segundo Código Mundial Antidoping da WADA. / Introduction: Considering that anti-inflammatory drugs are widely used in the athletic community because of their supposed improvement of performance due to their analgesic action, either in the presence of lesion or not, and the numerous reports of the adverse effects associated with this pharmacological class, the aim of the present Doctoral Dissertation was to investigate the possibility of nonsteroidal anti-inflammatory ibuprofen being fit to be considered as doping according to the World Anti-Doping Code of the World Anti-Doping Agency (WADA-COI), by the criteria of ergogeny and risk to health in athletes in long duration run. To that purpose, three randomized, double blind clinical trials were performed. Materials and Methods: In the first trial (laboratory setting), 14 athletes experienced in long duration runs were submitted to 2 progressive tests of running on treadmill with a 72-hour interval between the tests (crossover design), with oral administration of a single dose of 1.2g NSAID or placebo (lactose) before each test. The results showed that the use of NSAID reduced the perceived exertion at the second ventilatory threshold (p 0.01), yet with decreased associated speed (p=0.01) and reduced VO2máx (p=0.04). In the second trial, 20 fit healthy subjects (2x10 subjects), after determination of the speed associated with the second ventilatory threshold, were submitted to a limit time protocol for exhaustion (tlim) in run before and 48h after inducing muscle damage with concentric and eccentric exercises (in isokinetic dynamometer) in the muscle groups of the anterior and posterior thigh compartment. In the second test (postdamage), one group was given a single oral dose of 1.2g NSAID and the other, placebo. The results showed a significant reduction in tlim in both groups (p 0.01), still without attenuation of fall by the NSAID (p=0.55). In the third and last test, 14 athletes performed two 10-km simulated runs (SRs) on track with a 7-day interval. On each day the runners received the same pharmacological treatment as in the previous trials (crossover design) and had their glomerular filtration rate (GFR) monitored by the 51CrEDTA clearance rate technique as well as their performance (total time of test). In both runs a significant reduction in the GFR (p 0.01) was observed, yet with no difference between the situations of using NSAID and placebo (p=0,235). Performance was negatively affected by the drug (p=0,02). Specific conclusions: In experienced, fit runners and athletes, prophylactic Ibuprofen administration in oral single dose is potentially able to reduce performance as it is likely to adversely affect volemic distribution to the active tissue (an effect associated with reduction in tissue hyperemia and chronotropic response resulting from exercise). Its analgesic efficacy on attenuating acute (caused by the run) or late (caused by previous damage) discomfort Is not guaranteed as the pain X performance relation is concerned. Finally, a single dose of Ibuprofen administered before the run (in the conditions investigated here) does not potentialize the acute renal failure condition caused by the exercise itself. General conclusion: The present experimental model indicates that the use of non-steroidal anti-inflammatory Ibuprofen cannot be considered as doping according to the World Anti-Doping Code of the WADA.
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Análise da potencialidade ergogênica e riscos associados ao uso do antiinflamatório não-esteroidal ibuprofeno em corredores de endurance / Analysis of the ergogenic potential and risks associated with the use of non-steroidal anti-inflammatory ibuprofen in endurance runners

Silva, Eduardo Ramos da January 2009 (has links)
Introdução: Devido ao fato dos antiinflamatórios serem amplamente utilizados no meio atlético, da suposta melhora de desempenho pelo efeito analgésico, independentemente da presença ou não de lesão, e, por fim, em razão dos extensos relatos de efeitos adversos associados a esta classe farmacológica, o objetivo da presente Tese Doutoral foi verificar a potencialidade do antiinflamatório não-esteroidal (AINE) Ibuprofeno em enquadrar-se como doping segundo o Código Mundial Antidoping da Agência Mundial Antidoping (WADA-COI), segundo critérios de ergogenia e risco à saúde em atleta em corrida de duração. Para tanto, foram realizados um estudo observacional e três ensaios clínicos, randomizados e duplo-cego. Materiais e Métodos: No primeiro trabalho (laboratorial), 14 atletas especialistas em provas de longa duração realizaram dois testes progressivos de corrida em esteira rolante com 72 horas de intervalo (modelo cruzado), sendo administrada em cada teste dose única e por via oral de 1,2g de AINE ou Placebo (lactose). Os resultados indicaram que o uso de AINE reduziu a percepção de esforço no segundo limiar ventilatório (p 0,01), todavia com diminuição da velocidade associada (p=0,01) e redução do VO2máx (p=0,04). No segundo estudo, 20 sujeitos (2x10 sujeitos) condicionados e saudáveis, após determinação da velocidade associada ao segundo limiar ventilatório, foram submetidos a um protocolo de tempo limite para exaustão (tlim) em corrida antes e 48h após indução de dano muscular com exercícios concêntricos e excêntricos (em dinamômetro isoscinético) nos grupos musculares do compartimento anterior e posterior da coxa. No segundo teste (pós-dano) um grupo recebeu, em dose única e por via oral, 1,2g de AINE e o outro grupo Placebo. Os resultados indicaram redução significativa do tlim em ambos os grupos (p 0,01), contudo sem atenuação de queda pelo AINE (p=0,55). No terceiro e último experimento, 14 atletas realizaram duas provas simuladas (PS) de 10 km em pista com sete dias de intervalo. Em cada dia os sujeitos receberam tratamento farmacológico idêntico aos estudos anteriores (modelo cruzado) tendo sido monitorados a filtragem glomerular (FG) pela técnica de clearance de 51CrEDTA, assim como o desempenho (tempo total de teste). Em ambas PSs foi observada redução significativa da FG (p 0,01), porém sem diferenciação entre as situações de uso de AINE e Placebo (p=0,235). O desempenho foi impactado negativamente pelo fármaco (p=0,02). Conclusões específicas: em corredores condicionados e atletas, a administração profilática de Ibuprofeno em dose única por via oral possui potencial chance de redução do desempenho por impactar possivelmente a distribuição volêmica ao tecido ativo (efeito associado à redução de hiperemia tecidual e à resposta cronotrópica frente ao exercício). Não restou assegurada sua eficácia analgésica sobre a atenuação do desconforto agudo (gerado pela corrida) ou tardio (gerado por dano prévio) no que tange a relação dor X desempenho. E por fim, a administração de dose única deste Ibuprofeno antes da corrida (nas condições de análise), não potencializa a condição de insuficiência renal aguda gerada pelo próprio exercício. Conclusão geral: O presente modelo experimental indica que o uso do antiinflamatório não-esteroidal Ibuprofeno não apresenta potencialidade de enquadrar-se como doping segundo Código Mundial Antidoping da WADA. / Introduction: Considering that anti-inflammatory drugs are widely used in the athletic community because of their supposed improvement of performance due to their analgesic action, either in the presence of lesion or not, and the numerous reports of the adverse effects associated with this pharmacological class, the aim of the present Doctoral Dissertation was to investigate the possibility of nonsteroidal anti-inflammatory ibuprofen being fit to be considered as doping according to the World Anti-Doping Code of the World Anti-Doping Agency (WADA-COI), by the criteria of ergogeny and risk to health in athletes in long duration run. To that purpose, three randomized, double blind clinical trials were performed. Materials and Methods: In the first trial (laboratory setting), 14 athletes experienced in long duration runs were submitted to 2 progressive tests of running on treadmill with a 72-hour interval between the tests (crossover design), with oral administration of a single dose of 1.2g NSAID or placebo (lactose) before each test. The results showed that the use of NSAID reduced the perceived exertion at the second ventilatory threshold (p 0.01), yet with decreased associated speed (p=0.01) and reduced VO2máx (p=0.04). In the second trial, 20 fit healthy subjects (2x10 subjects), after determination of the speed associated with the second ventilatory threshold, were submitted to a limit time protocol for exhaustion (tlim) in run before and 48h after inducing muscle damage with concentric and eccentric exercises (in isokinetic dynamometer) in the muscle groups of the anterior and posterior thigh compartment. In the second test (postdamage), one group was given a single oral dose of 1.2g NSAID and the other, placebo. The results showed a significant reduction in tlim in both groups (p 0.01), still without attenuation of fall by the NSAID (p=0.55). In the third and last test, 14 athletes performed two 10-km simulated runs (SRs) on track with a 7-day interval. On each day the runners received the same pharmacological treatment as in the previous trials (crossover design) and had their glomerular filtration rate (GFR) monitored by the 51CrEDTA clearance rate technique as well as their performance (total time of test). In both runs a significant reduction in the GFR (p 0.01) was observed, yet with no difference between the situations of using NSAID and placebo (p=0,235). Performance was negatively affected by the drug (p=0,02). Specific conclusions: In experienced, fit runners and athletes, prophylactic Ibuprofen administration in oral single dose is potentially able to reduce performance as it is likely to adversely affect volemic distribution to the active tissue (an effect associated with reduction in tissue hyperemia and chronotropic response resulting from exercise). Its analgesic efficacy on attenuating acute (caused by the run) or late (caused by previous damage) discomfort Is not guaranteed as the pain X performance relation is concerned. Finally, a single dose of Ibuprofen administered before the run (in the conditions investigated here) does not potentialize the acute renal failure condition caused by the exercise itself. General conclusion: The present experimental model indicates that the use of non-steroidal anti-inflammatory Ibuprofen cannot be considered as doping according to the World Anti-Doping Code of the WADA.

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