A síndrome da imunodeficiência adquirida é causada pelo vírus da imunodeficiência humana e é caracterizada por provocar depleção física e funcional do sistema imune do organismo, através da infecção citopática de células CD4+. Muitos fármacos anti-retrovirais tem sido desenvolvidos e estão disponíveis comercialmente. Para atuar no controle de qualidade de medicamentos deve-se continuamente estudar o desenvolvimento e a validação de novas metodologias para quantificação de fármacos, para serem aplicadas nos estudos de estabilidade de formulações farmacêuticas e na análise de produtos de degradação. Neste trabalho foram utilizadas duas técnicas analíticas, a espectrofotometria direta no UV/VIS e a cromatografia líquida de alta eficiência (CLAE), para a determinação quantitativa de zidovudina (AZT) e estavudina (d4T).em medicamentos. Ambos os métodos foram validados com relação à linearidade, exatidão, precisão, especificidade e limite de detecção e quantificação. O método validado para a CLAE foi também empregado para a determinação quantitativa da timina, produto de degradação do AZT e da d4T. A metodologia validada por CLAE foi utilizada na realização de estudos de estabilidade acelerada dos anti-retrovirais contidos nas diferentes preparações farmacêuticas. Realizou-se o estudo da estabilidade em três diferentes condições: temperatura ambiente, 40 oC / 75% UR e 50 oC / 90% UR. Tanto a zidovudina (Fabricante A) e estavudina (Fabricante B) apresentaram decaimento cinético de zero ordem com prazos de validade a 50 oC / 90% UR de 10, 3 e 2 meses, respectivamente. / The acquired immunodeficiency syndrome is characterized by causing physical and functional depletion of the organism’s immune system, through the cytophatic infection of CD4+ cells. Several antiretroviral drugs has been developed and commercially made available. In order to assure the quality control of drugs it is necessary to develop and validate new analytical methodologies to perform the quantitative determination of drugs and stability studies of pharmaceutical formulations by determining the drug itself and its degradation products. In this research two analytical techniques, direct UV/VIS spectrophotometry and high performance liquid chromatography (HPLC), were used for the quantitative determination of zidovudine (AZT) and stavudine (d4T) in pharmaceutical preparations. Both methods were validated and parameters like linearity, precision, accuracy, specificity, limit of detection and limit of quantification, were determined. The validated HPLC method was also applied for quantitative determination of timine, a degradation product of AZT and d4T. The validated HPLC method was applied to accelerate stability studies of AZT and d4T in different pharmaceutical preparations. The stability studies were performed at three different conditions: room temperature, 40 oC / 75% RH and 50 oC / 90% RH. Both AZT and d4T (Industry A) and d4T (Industry B) pharmaceutical preparations presented a zero order degradation reaction. The three formulations presented a shelf-life of 10, 3 and 2 months, respectively, at 50 oC / 90% RH.

A síndrome da imunodeficiência adquirida é causada pelo vírus da imunodeficiência humana e é caracterizada por provocar depleção física e funcional do sistema imune do organismo, através da infecção citopática de células CD4+. Muitos fármacos anti-retrovirais tem sido desenvolvidos e estão disponíveis comercialmente. Para atuar no controle de qualidade de medicamentos deve-se continuamente estudar o desenvolvimento e a validação de novas metodologias para quantificação de fármacos, para serem aplicadas nos estudos de estabilidade de formulações farmacêuticas e na análise de produtos de degradação. Neste trabalho foram utilizadas duas técnicas analíticas, a espectrofotometria direta no UV/VIS e a cromatografia líquida de alta eficiência (CLAE), para a determinação quantitativa de zidovudina (AZT) e estavudina (d4T).em medicamentos. Ambos os métodos foram validados com relação à linearidade, exatidão, precisão, especificidade e limite de detecção e quantificação. O método validado para a CLAE foi também empregado para a determinação quantitativa da timina, produto de degradação do AZT e da d4T. A metodologia validada por CLAE foi utilizada na realização de estudos de estabilidade acelerada dos anti-retrovirais contidos nas diferentes preparações farmacêuticas. Realizou-se o estudo da estabilidade em três diferentes condições: temperatura ambiente, 40 oC / 75% UR e 50 oC / 90% UR. Tanto a zidovudina (Fabricante A) e estavudina (Fabricante B) apresentaram decaimento cinético de zero ordem com prazos de validade a 50 oC / 90% UR de 10, 3 e 2 meses, respectivamente. / The acquired immunodeficiency syndrome is characterized by causing physical and functional depletion of the organism’s immune system, through the cytophatic infection of CD4+ cells. Several antiretroviral drugs has been developed and commercially made available. In order to assure the quality control of drugs it is necessary to develop and validate new analytical methodologies to perform the quantitative determination of drugs and stability studies of pharmaceutical formulations by determining the drug itself and its degradation products. In this research two analytical techniques, direct UV/VIS spectrophotometry and high performance liquid chromatography (HPLC), were used for the quantitative determination of zidovudine (AZT) and stavudine (d4T) in pharmaceutical preparations. Both methods were validated and parameters like linearity, precision, accuracy, specificity, limit of detection and limit of quantification, were determined. The validated HPLC method was also applied for quantitative determination of timine, a degradation product of AZT and d4T. The validated HPLC method was applied to accelerate stability studies of AZT and d4T in different pharmaceutical preparations. The stability studies were performed at three different conditions: room temperature, 40 oC / 75% RH and 50 oC / 90% RH. Both AZT and d4T (Industry A) and d4T (Industry B) pharmaceutical preparations presented a zero order degradation reaction. The three formulations presented a shelf-life of 10, 3 and 2 months, respectively, at 50 oC / 90% RH.

<p>Antibody-drug conjugates (ADCs) combine the cytotoxicity of traditional chemotherapy with the site-specificity of antibodies by conjugating payloads to antibodies with immunoaffinity. However, the conjugation alters the physicochemical properties of antibodies, increasing the risks of various types of degradation. The effects of common risk factors such as pH, temperature, and light on the stability of ADCs differ from their effects on monoclonal antibodies (mAb) due to these altered physicochemical properties. </p> <p>To date, ADC researchers have developed linkers with improved <i>in vivo</i> stability, and begun to understand the deconjugation mechanisms <i>in vivo</i>. In contrast, the <i>in vitro</i> stability of ADCs has not gained comparable attention. All nine of the U.S. FDA approved ADCs are lyophilized to minimize the potential for degradation. However, there are few studies on the solid-state stability of ADCs. To evaluate lyophilized solids, pharmaceutical development relies heavily on accelerated stability studies, which take months to determine the best formulation. Characterization methods that are often used orthogonally with accelerated studies include Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, near-infrared spectroscopy (NIR), differential scanning calorimetry (DSC), and x-ray powder diffraction (XRPD). Results from these methods are often poorly correlated with stability, however. Thus, stability evaluation of solid-state ADC products, and other recombinant protein drugs, is often a bottleneck in their development.</p> <p>To provide knowledge on how to improve the <i>in vitro</i> stability of lyophilized ADC formulations, the solid-state stability of ADC formulations with varying risk factors was studied in this dissertation project. The first study investigated interactions between an ADC and excipients in terms of solid-state stability enhancement. The second study investigated the process-driven instability of ADCs during lyophilization using various concentrations of ADCs. The first two studies incorporate a new method called solid-state hydrogen/deuterium exchange coupled with mass spectrometry (ssHDX-MS) as an analytical predictor of solid-state stability. The last study investigated the effects of pH on the stability of labile hydrazones, as a model for common linker chemistry used in ADCs. </p>