Validação do método de doseamento para controle de qualidade do composto [11C] PiB

O número de pessoas com Doença de Alzheimer (DA) vem crescendo exponencialmente, podendo chegar a 74 milhões de casos no mundo em 2030. A patologia desta doença é caracterizada principalmente pelo acúmulo de depósitos de placas beta-amilóide no cérebro, se tornando uma ferramenta importante para indicação do diagnóstico neuropatológico da DA. Com isso, gerou-se grande interesse na descoberta de radiofármaco marcado com átomo emissor de pósitrons, capaz de se ligar a essas placas. O Composto B de Pittsburgh ([11C]PiB), foi o primeiro radiotraçador desenvolvido, com ligação específica às placas beta-amilóide no tecido cerebral, permitindo a visualização e quantificação dessas estruturas através da técnica PET (tomografia por emissão de pósitrons) de forma não invasiva. Entretanto, este radiofármaco não possui monografia oficial, devendo seguir guias gerais para realização do controle de qualidade desta molécula. Assim, o objetivo deste trabalho foi desenvolver e validar um método por CLAE para quantificação do PiB, para ser utilizado no controle de qualidade. O método proposto para quantificação do PiB mostrou-se específico, linear na faixa de concentração entre 1,0 e 4,2 μg/mL, sensível, preciso, exato e robusto.The number of people with Alzheimer's disease (AD) has been growing exponentially, possibly reaching the mark of 74 million cases in the world in 2030. The pathology of this disease is mainly characterized by the accumulation of deposits of beta-amyloid plaques in the brain, becoming an important tool to indicate the neuropathological diagnosis of AD. With this, great interest was generated in the discovery of radiopharmaceutical labeled with positron emission atom capable of binding to these plates. Pittsburgh Compound B ([11C] PiB), a molecule labeled with a radioactive carbon atom, was the first radiotracer developed with specific binding to beta-amyloid plaques in the brain tissue and can be visualized and quantified by PET (positrons emission tomography) noninvasively. However, this radiopharmaceutical has no official monograph and should follow general guides to carry out the quality control of this molecule. Thus, the aim of this study was to develop and validate a HPLC method for quantification of PiB, through a fast and efficient technique to be used in quality control. The proposed method for quantification of PiB showed to be specific, linear in the concentration range between 1.0 and 4.2 μg/mL, sensitive, precise, accurate and robust

Labeling the oily core of nanocapsules and lipid-core nanocapsules with a triglyceride conjugated to a fluorescent dye as a strategy to particle tracking in biological studies

The synthesis of novel fluorescent materials represents a very important step to obtain labeled nanoformulations in order to evaluate their biological behavior. The strategy of conjugating a fluorescent dye with triacylglycerol allows that either particles differing regarding supramolecular structure, i.e., nanoemulsions, nanocapsules, lipid-core nanocapsules, or surface charge, i.e., cationic nanocapsules and anionic nanocapsules, can be tracked using the same labeled material. In this way, a rhodamine B-conjugated triglyceride was obtained to prepare fluorescent polymeric nanocapsules. Different formulations were obtained, nanocapsules (NC) or lipid-core nanocapsules (LNC), using the labeled oil and Eudragit RS100, Eudragit S100, or poly(caprolactone) (PCL), respectively. The rhodamine B was coupled with the ricinolein by activating the carboxylic function using a carbodiimide derivative. Thin layer chromatography, proton nuclear magnetic resonance (¹H-NMR), Fourier transform infrared spectroscopy (FTIR), UV-vis, and fluorescence spectroscopy were used to identify the new product. Fluorescent nanocapsule aqueous suspensions were prepared by the solvent displacement method. Their pH values were 4.6 (NC-RS100), 3.5 (NC-S100), and 5.0 (LNC-PCL). The volume-weighted mean diameter (D₄.₃) and polydispersity values were 150 nm and 1.05 (NC-RS100), 350 nm and 2.28 (NC-S100), and 270 nm and 1.67 (LNC-PCL). The mean diameters determined by photon correlation spectroscopy (PCS) (z-average) were around 200 nm. The zeta potential values were +5.85 mV (NC-RS100), −21.12 mV (NC-S100), and −19.25 mV (LNC-PCL). The wavelengths of maximum fluorescence emission were 567 nm (NC-RS100 and LNC-PCL) and 574 nm (NC-S100). Fluorescence microscopy was used to evaluate the cell uptake (human macrophage cell line) of the fluorescent nanocapsules in order to show the applicability of the approach. When the cells were treated with the fluorescent nanocapsules, red emission was detected around the cell nucleus. We demonstrated that the rhodamine B-conjugated triglyceride is a promising new material to obtain versatile dye-labeled nanocarriers presenting different chemical nature in their surfaces

Labeling the oily core of nanocapsules and lipid-core nanocapsules with a triglyceride conjugated to a fluorescent dye as a strategy to particle tracking in biological studies

The synthesis of novel fluorescent materials represents a very important step to obtain labeled nanoformulations in order to evaluate their biological behavior. The strategy of conjugating a fluorescent dye with triacylglycerol allows that either particles differing regarding supramolecular structure, i.e., nanoemulsions, nanocapsules, lipid-core nanocapsules, or surface charge, i.e., cationic nanocapsules and anionic nanocapsules, can be tracked using the same labeled material. In this way, a rhodamine B-conjugated triglyceride was obtained to prepare fluorescent polymeric nanocapsules. Different formulations were obtained, nanocapsules (NC) or lipid-core nanocapsules (LNC), using the labeled oil and Eudragit RS100, Eudragit S100, or poly(caprolactone) (PCL), respectively. The rhodamine B was coupled with the ricinolein by activating the carboxylic function using a carbodiimide derivative. Thin layer chromatography, proton nuclear magnetic resonance (¹H-NMR), Fourier transform infrared spectroscopy (FTIR), UV-vis, and fluorescence spectroscopy were used to identify the new product. Fluorescent nanocapsule aqueous suspensions were prepared by the solvent displacement method. Their pH values were 4.6 (NC-RS100), 3.5 (NC-S100), and 5.0 (LNC-PCL). The volume-weighted mean diameter (D₄.₃) and polydispersity values were 150 nm and 1.05 (NC-RS100), 350 nm and 2.28 (NC-S100), and 270 nm and 1.67 (LNC-PCL). The mean diameters determined by photon correlation spectroscopy (PCS) (z-average) were around 200 nm. The zeta potential values were +5.85 mV (NC-RS100), −21.12 mV (NC-S100), and −19.25 mV (LNC-PCL). The wavelengths of maximum fluorescence emission were 567 nm (NC-RS100 and LNC-PCL) and 574 nm (NC-S100). Fluorescence microscopy was used to evaluate the cell uptake (human macrophage cell line) of the fluorescent nanocapsules in order to show the applicability of the approach. When the cells were treated with the fluorescent nanocapsules, red emission was detected around the cell nucleus. We demonstrated that the rhodamine B-conjugated triglyceride is a promising new material to obtain versatile dye-labeled nanocarriers presenting different chemical nature in their surfaces