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A ambrisentana é um novo fármaco utilizado para o combate aos sintomas da hipertensão arterial pulmonar e comercializado na forma de comprimidos revestidos. Em 201 O, sua comercialização foi aprovada pela ANVISA, sob nome comercial de Volibris®. O controle de qualidade de medicamentos é parte fundamental para o desenvolvimento e liberação de fármacos para o consumo, no entanto, há poucos estudos relacionados à proposição de métodos analíticos e estudo da estabilidade deste fárrnaco. Assim, foi proposto o desenvolvimento e validação de método de doseamento e análise de produtos de degradação, juntamente com a identificação da molécula proveniente da degradação do insumo ativo em condição de estresse térmico. Um método crornatográfico, com utilização de equipamento de cromatografia UPLC ®, acoplado a detector de arranjo de fotodiodos (PDA), foi desenvolvido. Testes com diferentes solventes e diferentes colunas cromatográficas foram executados, alcançando-se a urna condição ideal, com excelente qualidade crornatográfica (pratos teóricos, sensibilidade e resolução entre picos) e um reduzido tempo de análise (6 minutos). Este método foi validado de acordo com os guias de validação internacionais e após a finalização dos ensaios e interpretação dos resultados, verificou-se que o método apresenta especWicidade adequada, tanto para análise de doseamento da substância ativa como para identificação e quantWicação de produtos de degradação. Também apresentou exatidão e precisão dentro do esperado para utilização em controle da qual idade de produtos farmacêuticos, tendo também limites de quantificação e detecção em magnitude adequada para se avaliar a possível degradação do fármaco. O método se apresentou linear no intervalo pretendido e com robustez satisfatória. Com o estresse da molécula estabelecido no desenvolvimento e va lidação da metodologia analítica, o principal produto de degradação foi identificado por detecção em espectrometria de massas após separação cromatográfica em sistema composto de UPLC®- EM/EM. A molécula proveniente da degradação do fármaco foi identificada, e teve o seu mecanismo de degradação proposto, concluindo-se que a presença da ambrisentana em ambientes ácidos pode desencadear a degradação da molécula, facilitada ainda por temperatura. / The ambrisentana is a new drug used to combat the symptoms of pulmonary arterial hypertension and marketed in the form of coated tablets. In 2010, its commercialization was approved by ANVISA, under trade name Volibris®. The quality control of medicines is a fundamental part for the development and release of drugs for consumption, however, there are few studies related to the proposition of analytical methods and study the stability of the drug. Thus, we propose the development and validation of appropriate method to assay the drug and degradation products, and the identification of degradation product obtained in stress conditions. A chromatographic method using UPLC ® chromatography equipment coupled to photodiode array detector (PDA) have been developed. Tests with different solvents and different chromatographic columns were performed, reaching up to an optimal chromatographic condition (theoretical plates, sensitivity, and resolution between peaks) and reduced chromatographic run time (6 minutes). This method was validated in accordance with international guidelines and va lidation after the completion of the tests and interpret the results, it was found that the method has adequate specificity for both analysis, assay of the active principie for identification and quantification of degradation products. Also presented accuracy and precision as expected for use in quality control of pharmaceuticals, and limits of quantification and detection at adequate leveis to assess the possible degradation of the drug. The method was linear in the target range and with satisfactory robustness. With the stress of established molecule in the development and validation of analytical methodology, was identified the main degradation product by mass spectrometry detection after chromatographic separation of compound UPLC® system. The molecule from the drug degradation was identified, and had its proposed degradation mechanism, concluding that the presence of ambrisentana in acidic can trigger the degradation of the molecule, ais o facilitated by temperature.

A ambrisentana é um novo fármaco utilizado para o combate aos sintomas da hipertensão arterial pulmonar e comercializado na forma de comprimidos revestidos. Em 201 O, sua comercialização foi aprovada pela ANVISA, sob nome comercial de Volibris®. O controle de qualidade de medicamentos é parte fundamental para o desenvolvimento e liberação de fármacos para o consumo, no entanto, há poucos estudos relacionados à proposição de métodos analíticos e estudo da estabilidade deste fárrnaco. Assim, foi proposto o desenvolvimento e validação de método de doseamento e análise de produtos de degradação, juntamente com a identificação da molécula proveniente da degradação do insumo ativo em condição de estresse térmico. Um método crornatográfico, com utilização de equipamento de cromatografia UPLC ®, acoplado a detector de arranjo de fotodiodos (PDA), foi desenvolvido. Testes com diferentes solventes e diferentes colunas cromatográficas foram executados, alcançando-se a urna condição ideal, com excelente qualidade crornatográfica (pratos teóricos, sensibilidade e resolução entre picos) e um reduzido tempo de análise (6 minutos). Este método foi validado de acordo com os guias de validação internacionais e após a finalização dos ensaios e interpretação dos resultados, verificou-se que o método apresenta especWicidade adequada, tanto para análise de doseamento da substância ativa como para identificação e quantWicação de produtos de degradação. Também apresentou exatidão e precisão dentro do esperado para utilização em controle da qual idade de produtos farmacêuticos, tendo também limites de quantificação e detecção em magnitude adequada para se avaliar a possível degradação do fármaco. O método se apresentou linear no intervalo pretendido e com robustez satisfatória. Com o estresse da molécula estabelecido no desenvolvimento e va lidação da metodologia analítica, o principal produto de degradação foi identificado por detecção em espectrometria de massas após separação cromatográfica em sistema composto de UPLC®- EM/EM. A molécula proveniente da degradação do fármaco foi identificada, e teve o seu mecanismo de degradação proposto, concluindo-se que a presença da ambrisentana em ambientes ácidos pode desencadear a degradação da molécula, facilitada ainda por temperatura. / The ambrisentana is a new drug used to combat the symptoms of pulmonary arterial hypertension and marketed in the form of coated tablets. In 2010, its commercialization was approved by ANVISA, under trade name Volibris®. The quality control of medicines is a fundamental part for the development and release of drugs for consumption, however, there are few studies related to the proposition of analytical methods and study the stability of the drug. Thus, we propose the development and validation of appropriate method to assay the drug and degradation products, and the identification of degradation product obtained in stress conditions. A chromatographic method using UPLC ® chromatography equipment coupled to photodiode array detector (PDA) have been developed. Tests with different solvents and different chromatographic columns were performed, reaching up to an optimal chromatographic condition (theoretical plates, sensitivity, and resolution between peaks) and reduced chromatographic run time (6 minutes). This method was validated in accordance with international guidelines and va lidation after the completion of the tests and interpret the results, it was found that the method has adequate specificity for both analysis, assay of the active principie for identification and quantification of degradation products. Also presented accuracy and precision as expected for use in quality control of pharmaceuticals, and limits of quantification and detection at adequate leveis to assess the possible degradation of the drug. The method was linear in the target range and with satisfactory robustness. With the stress of established molecule in the development and validation of analytical methodology, was identified the main degradation product by mass spectrometry detection after chromatographic separation of compound UPLC® system. The molecule from the drug degradation was identified, and had its proposed degradation mechanism, concluding that the presence of ambrisentana in acidic can trigger the degradation of the molecule, ais o facilitated by temperature.

A ambrisentana é um novo fármaco utilizado para o combate aos sintomas da hipertensão arterial pulmonar e comercializado na forma de comprimidos revestidos. Em 201 O, sua comercialização foi aprovada pela ANVISA, sob nome comercial de Volibris®. O controle de qualidade de medicamentos é parte fundamental para o desenvolvimento e liberação de fármacos para o consumo, no entanto, há poucos estudos relacionados à proposição de métodos analíticos e estudo da estabilidade deste fárrnaco. Assim, foi proposto o desenvolvimento e validação de método de doseamento e análise de produtos de degradação, juntamente com a identificação da molécula proveniente da degradação do insumo ativo em condição de estresse térmico. Um método crornatográfico, com utilização de equipamento de cromatografia UPLC ®, acoplado a detector de arranjo de fotodiodos (PDA), foi desenvolvido. Testes com diferentes solventes e diferentes colunas cromatográficas foram executados, alcançando-se a urna condição ideal, com excelente qualidade crornatográfica (pratos teóricos, sensibilidade e resolução entre picos) e um reduzido tempo de análise (6 minutos). Este método foi validado de acordo com os guias de validação internacionais e após a finalização dos ensaios e interpretação dos resultados, verificou-se que o método apresenta especWicidade adequada, tanto para análise de doseamento da substância ativa como para identificação e quantWicação de produtos de degradação. Também apresentou exatidão e precisão dentro do esperado para utilização em controle da qual idade de produtos farmacêuticos, tendo também limites de quantificação e detecção em magnitude adequada para se avaliar a possível degradação do fármaco. O método se apresentou linear no intervalo pretendido e com robustez satisfatória. Com o estresse da molécula estabelecido no desenvolvimento e va lidação da metodologia analítica, o principal produto de degradação foi identificado por detecção em espectrometria de massas após separação cromatográfica em sistema composto de UPLC®- EM/EM. A molécula proveniente da degradação do fármaco foi identificada, e teve o seu mecanismo de degradação proposto, concluindo-se que a presença da ambrisentana em ambientes ácidos pode desencadear a degradação da molécula, facilitada ainda por temperatura. / The ambrisentana is a new drug used to combat the symptoms of pulmonary arterial hypertension and marketed in the form of coated tablets. In 2010, its commercialization was approved by ANVISA, under trade name Volibris®. The quality control of medicines is a fundamental part for the development and release of drugs for consumption, however, there are few studies related to the proposition of analytical methods and study the stability of the drug. Thus, we propose the development and validation of appropriate method to assay the drug and degradation products, and the identification of degradation product obtained in stress conditions. A chromatographic method using UPLC ® chromatography equipment coupled to photodiode array detector (PDA) have been developed. Tests with different solvents and different chromatographic columns were performed, reaching up to an optimal chromatographic condition (theoretical plates, sensitivity, and resolution between peaks) and reduced chromatographic run time (6 minutes). This method was validated in accordance with international guidelines and va lidation after the completion of the tests and interpret the results, it was found that the method has adequate specificity for both analysis, assay of the active principie for identification and quantification of degradation products. Also presented accuracy and precision as expected for use in quality control of pharmaceuticals, and limits of quantification and detection at adequate leveis to assess the possible degradation of the drug. The method was linear in the target range and with satisfactory robustness. With the stress of established molecule in the development and validation of analytical methodology, was identified the main degradation product by mass spectrometry detection after chromatographic separation of compound UPLC® system. The molecule from the drug degradation was identified, and had its proposed degradation mechanism, concluding that the presence of ambrisentana in acidic can trigger the degradation of the molecule, ais o facilitated by temperature.

Hemodialysis (HD) is the most frequently used treatment for end-stage renal disease. Despite all efforts to improve the outcomes, the mortality of patients on HD is still high, and this especially is related to cardiovascular diseases (CVD). Glucose degradation products accumulate in plasma and tissue as a result of oxidative stress in these patients. Such accumulation is strongly related to the risk of developing CVD. Tissue deposits of advanced glycation end products (AGE) can be easily assessed by a skin autofluorescence (SAF) technique. SAF is one of the strongest prognostic markers of mortality in HD patients. The aim of this thesis is to examine whether intervention on HD treatment can reduce the load of AGE of these patients. The aim of the first study was to investigate whether changes in SAF appear after a single HD session and if they might be related to changes in plasma AF. Skin and plasma AF (PAF) were measured before and after HD in 35 patients on maintenance HD therapy. Median dialysis time was 4 h (range 3-5.5). SAF was measured noninvasively with an AGE Reader, and plasma AF was measured before and after HD. The HD patients had on average a 65% higher SAF value than age-matched healthy persons (P < 0.001). PAF was reduced by 14% (P < 0.001), whereas SAF was not changed after a single HD treatment. No significant influence of the reduced PAF on SAF levels was found. This suggests that the measurement of SAF can be performed during the whole dialysis period and is not directly influenced by the changes in plasma AF during HD. In study 2 different dialysis filters were compared to clarify whether using a high-flux (HF) dialyzer favors plasma or SAF removal compared to low-flux (LF) dialyzer. Twenty-eight patients were treated with either an HF-HD or LF-HD but otherwise unchanged conditions in a cross-over design. SAF was measured non-invasively with an AGE reader before and after HD. PAF was determined as total and non-protein-bound fractions. Corrections for hemoconcentrations by volume changes were made using the change in serum albumin. Paired and non-paired statistical analyses were used. The different treatments did not change SAF after LF- and HF-dialysis. Total, free, and protein-bound PAF were reduced after a single LF-HD by 21%, 28%, and 17%, respectively (P<.001). After HF-HD total and free PAF was reduced by 5% and 15%, respectively (P<.001), while protein-bound values were unchanged. The LF-HD resulted in a more pronounced reduction of PAF than did HF-HD (P<.001). Serum albumin correlated inversely with PAF in HF-HD. There was no significant change in SAF after dialysis, either with LF or with HF dialysis. Although only limited reductions in PAF were observed, these were more pronounced when performing LF dialysis. These data are not in overwhelming support of the use of HF dialysis in the setting used in this study. In the third study the effect on SAF was investigated using either glucose-containing or glucose-free dialysate. SAF and PAF were measured in patients on HD during standard treatment with a glucose-containing dialysate (n=24). After that, the patients were switched to a glucose-free dialysate for a 2 week period, and new measurements were performed on PAF and SAF. There was an increase of pre-dialysis SAF measured at the beginning of the study compared with the values one month later (as in study 4). By comparing pre- and post-dialysis values there was a significant decrease of SAF only when using glucose-free dialysate. Free PAF decreased independently whether glucose-containing or glucose-free dialysate was used. The important finding was that increase in SAF seemed possible to slow down using glucose-free dialysate. Study 4 was performed to investigate whether there are seasonal variations in SAF on a HD population. SAF was measured non-invasively with an AGE Reader in patients on HD at different seasonal periods during one year such as February-May (N=31), May–August (N=28), August–March (N=25). SAF was measured before HD. Paired statistical analyses were performed between each two periods.  Unexpectedly there was at a median 6% increase in SAF during the winter (p=0.004) and a 11% decrease from 4.0 to 3.5 arbitrary units of the SAF during the summer (p<0.001). The study concluded that SAF shows seasonal variation. The cause of these changes could not be clarified. A beneficial effect may be due to extended exposure to sunlight during the summer and/or to different dietary intakes during the seasons. In conclusion, these interventional studies confirmed that PAF is lowered by dialysis. SAF was only decreased by HD when using glucose-free dialysate. SAF was not influenced by a single HD, with glucose-containing dialysate, independent of using HF or LF filters. These data favor glucose-free dialysate as a possible measure to slow down the progress of tissue AGE compared to glucose-containing dialysate. Longitudinal studies will help to clarify this issue further.

Phoslactomycin B (PLM-B), a potent and selective inhibitor of serine threonine phosphatase is of interest for its antitumor, antifungal and antiviral activity. The objective of this study was to evaluate the stability of phoslactomycin B at various pH and temperature conditions. Phoslactomycin B was produced from the mutant strain NP1 of Streptomyces sp.HK-803 and was purified by semi-preparative HPLC . A study of PLM-B degradation was carried out in the pH range of 2-10 at 30ºC and 50°C using HPLC. The PLM-B decomposition was observed to exhibit a U-shaped pH profile and demonstrated both acid and base-catalyzed decomposition. The decomposition could be described by the equation kOBS = kH x 10-pH + kOH x 10 pH- 14 (kH = 45±7 M-1 h-1; kOH = 448± 73 M-1 h-1). PLM-B was found to be most stable at pH 6.63. The degradation products in both acidic and basic pH have been collected and analyzed. Under basic condition, mass spectroscopic analysis revealed addition of water and NMR was consistent with the major products being formed due to lactone ring opening and/or a Micheal type addition reaction. Under acidic condition MS revealed loss of water for all three compounds. NMR analysis of one product (product 8) was consistant with C9- C11 phosphorinane derivative of PLM-B. The remaining compounds were shown to be mixture of various dehydration products. The degradation products despite containing small structural changes to PLM-B lost all detectable levels of antifungal activity.

Apixabana é um novo fármaco da classe dos anticoagulantes orais utilizado na prevenção e no tratamento de eventos de tromboembolismo venoso em pacientes submetidos à cirurgia de quadril e joelho, além de reduzir os riscos de acidente vascular cerebral e fibrilação arterial. Uma vez que impurezas e contaminantes podem estar presentes no produto farmacêutico final, as agências regulatórias preveem leis para monitorar essas substâncias. O conceito de Quality by Design (QbD), uma abordagem sistemática que inicia com objetivos pré-definidos e análise de risco, está sendo amplamente utilizado no âmbito farmacêutico para desenvolver formulações e metodologias analíticas. Sendo assim, este trabalho almejou desenvolver e validar um método indicativo de estabilidade simples, rápido e sensível utilizando cromatografia líquida de alta eficiência (CLAE) para determinação simultânea da apixabana e três impurezas sintéticas aplicando a abordagem QbD. O desenho experimental foi feito através do software MODDE® 11 (Umetrics, Suíça) e executado utilizando um cromatógrafo Shimadzu® LC-20A Prominence CLAE-DAD com detecção a 220 nm. O método cromatográfico foi estabelecido utilizando uma coluna Inertsil® CN-3 (150 × 4,6 mm, 5,0 μm) com temperatura do forno de 30°C e volume de injeção de 10 μL. A constituição da fase móvel foi metanol e água (50,2:49,8) com fluxo de 1,015 mL/min sem ajuste de pH. O método foi validado seguindo as guias do ICH e da ANVISA, sendo considerado específico, sensível, linear (r > 0,999), preciso (DPRs < 10% para as impurezas) e exato. Para especificidade, foi realizada busca de produtos de degradação submetendo os comprimidos de apixabana a condições de estresse (radiação UVC, temperatura, oxidação e hidrólise). As substâncias envolvidas no presente trabalho também foram caracterizadas quimicamente e avaliadas quanto ao seu perfil toxicológico in vitro através dos ensaios de MTT e vermelho neutro. A mistura da APX e suas impurezas demonstrou toxicidade aguda, porém este resultado não se manteve durante a exposição prolongada, sugerindo um mecanismo de compensação mitocondrial. Já a impureza 3 apresentou danos significativos em 96 horas de exposição, de modo que mais estudos devem efetuados para avaliar sua toxicidade. / Apixaban is a novel anticoagulant agent used to prevent and treat venous thromboembolic events in adults who have undergone total hip or knee replacement surgery and to lower the risk of stroke in patients with atrial fibrillation. As impurities and contaminants may be present in the pharmaceutical product, current regulatory guidelines recommend monitoring such substances. The concept of Quality by Design (QbD), a systematic approach that begins with predefined objectives and risk management, is being widely used in the pharmaceutical field to develop new formulations and analytical methods. Thus, the aim of this work was to develop and validate a simple, fast and sensitive stability indicating method by high-performance liquid chromatography (HPLC) for the simultaneous determination of apixaban and three synthesis impurities using QbD approach. Experiments were designed and assessed on MODDE® 11 (Umetrics, Sweden) software and carried out in a Shimadzu® LC-20A Prominence HPLC-DAD at 220 nm. The HPLC method was established using an Inertsil® CN-3column (150 × 4.6 mm, 5.0 μm) at the temperature of 30°C and injection volume of 10 μL. The mobile phase consisted of methanol and water (50.2:49.8) at a flow rate of 1.015 mL/min with no pH adjustment. Validation of the method was conducted according to ICH and ANVISA Guidelines, which was considered specific, sensitive, linear (r > 0,999), precise (RSD < 10% for impurities) and accurate. For specificity, a degradation study was performed by exposing apixaban tablets to stress conditions (UVC radiation, temperature, oxidation and hydrolysis). The related substances in the present study were also chemically characterized and toxicological profile was evaluated by in vitro tests MTT and neutral red. The mixture of APX and its impurities showed acute toxicity, but this result did not persist during prolonged exposure, suggesting a mitochondrial compensation mechanism. Yet, impurity 3 presented significant damages in 96 hours of exposure and further studies should be considered to evaluate its toxicity.

O ticagrelor é um novo fármaco destinado para a prevenção de síndromes coronarianas agudas (SCA) caracterizadas pela formação de placas ateroscleróticas que se rompem no interior das artérias. Atua de forma diferenciada na inibição da ação plaquetária, inibindo de forma reversível e não competitiva o receptor P2Y12, o qual atua diretamente na agregação das plaquetas. Este medicamento está registrado no Brasil desde 2011, sob nome comercial de Brilinta®, na forma de comprimidos revestidos de 90 mg, e, até o presente momento, são poucos os estudos publicados a respeito do controle de impurezas e produtos de degradação do fármaco. No presente trabalho foi desenvolvido um método por cromatografia líquida de alta eficiência (CLAE) adaptado para a análise de impurezas orgânicas do ticagrelor. O método por CLAE foi estabelecido utilizando equipamento Agilent 1200 Series, acoplado a detector de arranjo de diodos (DAD) em 270 nm, com coluna cromatográfica Zorbax Plus C8 (150 x 4,6 mm, 5,0 μm), fluxo de 0,7 ml/min, volume de injeção de 20 μl e temperatura constante de 25ºC. A fase móvel foi composta de acetonitrila: acetato de amônio 50 mM (57:43, v/v), pH 8,2. O método demonstrou ser específico, linear, preciso, exato e robusto, sendo adequado para a finalidade a que foi proposto. Além disso, foram elucidados os principais produtos de degradação originados quando as amostras dos comprimidos de ticagrelor em solução foram expostas à radiação UVC por duas horas, com base em um estudo preliminar de estabilidade do mesmo. Os mecanismos envolvidos na degradação fotolítica do ticagrelor também foram propostos. / Ticagrelor is a new drug intended for the prevention of acute coronary syndromes (ACS) characterized by the formation of atherosclerotic plaques that rupture inside the arteries. Ticagrelor reversibly binds to P2Y12 receptor, which acts directly on platelet aggregation. The drug was approved in Brazil in 2011, under the comercial name Brilinta® in the form of coated tablets of 90 mg, and until now has few published studies about the impurities control and degradation products. In this study, it was developed a method by high-performance liquid chromatography (HPLC) for the analysis of organic impurities of ticagrelor. The HPLC method was established using Agilent 1200 Series equipment coupled to photodiode array detector (PDA) at 270 nm with a Zorbax Plus C8 column (150 x 4.6 mm, 5.0 μm), flow rate of 0.7 ml/min, injection volume of 20 μL, and a constant temperature of 25°C. The mobile phase consisted of acetonitrile: ammonium acetate 50 mM (57:43 v/v), pH 8.2. The method demonstrated to be specific, linear, precise, accurate and robust, being suitable for the intended purpose. Besides, the mayor degradation products formed when samples of ticagrelor tablets in solution were exposed to UVC radiation for two hours were elucidated based on a preliminary stability study. The mechanisms involved in photolytic degradation of ticagrelor have also been proposed.

Submitted by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2016-09-21T18:28:49Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) FABIO DE SOUZA BARBOSA.pdf: 1689958 bytes, checksum: 1fe429224460761440aa3dfeb3cbe066 (MD5) / Approved for entry into archive by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2016-09-21T18:29:20Z (GMT) No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) FABIO DE SOUZA BARBOSA.pdf: 1689958 bytes, checksum: 1fe429224460761440aa3dfeb3cbe066 (MD5) / Made available in DSpace on 2016-09-21T18:29:20Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) FABIO DE SOUZA BARBOSA.pdf: 1689958 bytes, checksum: 1fe429224460761440aa3dfeb3cbe066 (MD5) Previous issue date: 2015-07-17 / O doripenem é um antibiótico β-lactâmico de amplo espectro de ação. Pertencente ao grupo das carbapenemas, caracteriza-se por apresentar elevada potência e atividade frente à cepas Gram-negativas, produtoras de β-lactamases de espectro estendido (ESBL) e β-lactamases ampC. Apesar de sua grande importância clínica, os antibióticos carbapenêmicos não apresentam boa estabilidade quando em solução, o que é demonstrado em diversos trabalhos descritos na literatura científica. Para o doripenem, há vários trabalhos descritos na literatura que ressaltam sua importância clínica e sua atividade antibiótica. Porém, nota-se a escassez de trabalhos que enfoquem sua estabilidade físico-química, seus produtos e suas rotas de decomposição. O presente trabalho tem como objetivo a validação de um método analítico indicativo de estabilidade por ultra fast liquid chromatography (UFLC), e a avaliação da estabilidade do doripenem em solução, quando submetido a estresse térmico, oxidativo, fotólise e hidrólise em meio ácido e meio alcalino, e determinação da cinética química de decompsição. Para proposição da estrutura química dos produtos de degradação, foram realizadas análises por cromatografia líquida com detecção por espectrometria de massas (LC-MS). O método cromatográfico descrito neste trabalho demonstrou-se adequado para determinação do doripenem na forma de pó para solução injetável, possuindo performance indicativa de estabilidade. A faixa linear do método foi de 5,0 a 40,0 μg/mL, sem desvios de linearidade, sendo estatisticamente comprovada por meio de ANOVA. Com o auxilio do desenho experimental de Plackett–Burman, o método demonstrou-se robusto frente a uma série de fatores. O estudo de degradação forçada demostrou a susceptibilidade do doripenem a diversos fatores de degradação, com acentuada instabilidade frente à hidrólise ácida e alcalina, observando-se degradação aproximada de 60% do seu teor em apenas 2 minutos sob condições alcalinas. A decomposição oxidativa do fármaco seguiu uma cinética de segunda ordem, com constante de velocidade de reação de 0,000086 e 0,00010%-1.min-1, quando submetido à degradação em H2O2 a 3 e 10%, respectivamente. A decomposição térmica apresentou uma energia de ativação de aproximadamente 15 Kcal/mol, valor característico de reações de hidrólise. E na análise cromatográfica com detecção por espectrometria de massas, observou-se que os principais produtos de degradação formados sob condições de termólise e oxidação, apresentam massas moleculares semelhantes, sendo possível a proposição da estrutura química dos mesmos. / Doripenem is a β-lactam antibiotic with a broad spectrum of antimicrobial activity, including gram-negative strains, and producers of extended spectrum β-lactamases (ESBL) and ampC β-lactamases ampC. Despite its great clinical importance, carbapenems do not show good stability when incorporated as solution, as reported in several studies. In reference to doripenem, several works have describing its clinical use, efficacy data and cases of resistance. However, few works mention the drug stability, in terms of degradation products and routes of decomposition. The present work aimed to develop and validate a stability-indicating method by ultra-fast liquid chomatograph (UFLC) for doripenem in powder for injection, purposing an evaluation of stability of reconstituted solution using stress conditions of heat, oxidation, acid hydrolysis, alkaline hydrolysis and photolysis. The chemical kinetic of decomposition was also assayed for thermal and oxidative degradation. For identification of degradation products, the degraded samples where submitted to analysis by LC-MS. The chromatographic method described here proved to be stability-indicating and suitable for the determination of doripenem in drug formulation. The method linearity was performed in the range of 5 to 40 g mL-1, whose correlation coefficient (r) was 0.9999. The robustness testing, assayed against a variety of factors, allowed verifying that the method accept small variations in routine analysis. The forced degradation demonstrated the susceptibility of doripenem to several decomposition factors, being intense the instability to acidic and alkaline hydrolysis. In basic media, the drug residual content was approximately 40% in 2 minutes. At oxidative decomposition, the drug follows second-order kinetics, with a rate reaction of 0.000086 and 0.00010 %-1 min-1, respectively for H2O2 at 3.0 and 10.0 %. The thermal decomposition showed an activation energy of 15 kcal mol-1, a characteristic value for hydrolysis reactions. The analysis by LC-MS revealed that the major degradation products formed under oxidizing conditions and thermolysis present molecular weight (411, 427, 437, 634, 650 and 664). The stability of doripenem must be carefully observed, mainly after reconstitution and storage in adverse conditions of temperature.

Un protocole d’altération de lubrifiants par NO2 en laboratoire a été développé pour étudier les effets de la nitroxydation sur les additifs et la base hydrocarbonée de lubrifiants moteur et comprendre leurs mécanismes d’altération. Des structures de produits d’altération et des voies de transformation ont pu être proposées ainsi que les facteurs contrôlant les cinétiques de dégradation des additifs. Les interactions entre les constituants de lubrifiants tant au niveau des cinétiques de dégradation que des structures des produits de dégradation ont ainsi été identifiées, notamment à partir d’un plan d’expériences. L’évolution des lubrifiants simulée en laboratoire n’est pas directement superposable à celle observée avec des essais moteur, un certain nombre de produits d’altération n’ayant pas été détectés en essais moteur. En revanche, les interactions contrôlant les cinétiques de dégradation des additifs sont proches dans les cas des expériences de laboratoire et des essais moteur. / An alteration laboratory protocol of lubricants by NO2 has been developed in order to investigate the effects of nitroxidation on base oil and additives from engine lubricants, and to understand the different mechanisms involved. The structure of alteration products and their transformation pathways have been proposed, as well as the factors that control the degradation kinetics of the additives. Interactions between lubricant constituents have been identified at the degradation kinetic level as well as the level of the alteration products formed, notably by means of an experimental design. The fate of lubricants in the laboratory experiments does not exactly match that observed in the case of engine tests, notably regarding the absence of formation of some degradation products. However, the interactions controlling the degradation kinetics of lubricant additives are close between laboratory experiments and engine tests.