Abstract In this study, a dichloromethane fraction dry extract from the underground parts of Jatropha isabellei (DFJi) was used to prepare lipid nanocarriers (LNCJi) aimed at providing the oral delivery of terpenic compounds in the treatment of arthritis. The lipid nanocarriers were prepared by the spontaneous emulsification method. The lipid nanocarriers displayed sizes ranging from 180 to 200 nm and zeta potential values of around -18 mV. A high value of entrapment efficiency (> 90%) was obtained for jatrophone, which was used as the chemical marker of DFJi. LNCJi stored at 4°C were demonstrated to be stable through measurements of transmitted light after analytical centrifugation of the samples. In vitro drug release studies conducted in biorelevant dissolution media demonstrated that jatrophone release was faster from LNCJi than from free DFJi. When tested in an acute arthritis model, the LNCJi exhibited antinociceptive properties after oral administration of a 50 mg/kg dose, unlike the free DFJi, although no reduction in articular diameter was observed. These results suggest that an increase in the oral absorption of DFJi constituents may have occurred through the carrying of this fraction in LNCJi, thus improving the antinociceptive activity of this compound.

In this study, we investigated the feasibility to obtain nanoparticles (NPs) by assembling pramlintide (Pram) with dextran sulfate (DexS), as a new approach for mucosal peptide delivery. DexS/Pram NPs were prepared by dropwise addition of a Pram solution to a DexS solution under magnetic stirring. The physicochemical characteristics of NPs and molecular interactions involved in the co-assembling were evaluated by dynamic light scattering (DLS), transmission electronic microscopy (TEM), isothermal titration microcalorimetry, Fourier-transform infrared spectroscopy (FTIR), fluorescence quenching, and circular dichroism (CD). DexS/Pram NPs displayed a narrow size distribution (ca. 200 nm), negative zeta potential (ca. −40 mV), association efficiency close to 100%, and nanogel behavior. The assembling with DexS increased the Pram α-helical content, stabilizing the peptide in its bioactive form. The colloidal stability of nanoparticles was dependent on the salt concentration and it could be assumed that peptide release from nanoparticles occurs by dissociation of the complex at physiological conditions.

In this study, a high-performance liquid chromatography with photodiode array detector (HPLC-PDA) method was developed and validated to simultaneously determine curcumin (CUR) and melatonin (MEL) in hyaluronic acid-coated nanoemulsions, a novel targetable delivery system to CD44 receptors overexpressed in many types of tumors. Chromatographic analyses were performed in reversed phase mode using a mobile phase consisting of acetonitrile, methanol and 0.1% formic acid (35:15:50, v/v/v) at a flow rate of 1 mL min-1, and detection at 223 and 425 nm. The method was successfully validated according to the parameters of specificity, linearity, limits of detection (LOD) and quantification (LOQ), inter/intra-day precision, accuracy, and robustness. Linearity was demonstrated in the CUR and MEL concentration range of 0.5-20.0 µg mL-1 and 1.0-40.0 µg mL-1 (r > 0.999), respectively. Relative standard deviation (RSD) values for intra-day and inter-day precision were lower than 5%, and mean drug recovery varied from 94.91 to 98.33%. Mean drug content of 85.2 and 501.4 µg mL-1 and entrapment efficiency of about 80 and 20% were obtained for CUR and MEL, respectively. These results may be correlated to the differences in the drug solubility of these drugs in the oil and water phases of the nanoemulsion.

RESUMO Os carotenoides compreendem uma classe de mais de 600 pigmentos naturais, cujo potencial biológico está relacionado à sua atividade antioxidante, regulação do crescimento celular, modulação da resposta imune e da atividade anti-inflamatória. A Haematococcus pluvialis é uma microalga verde, conhecida por sintetizar e acumular grandes quantidades de carotenoides, entre estes a astaxantina. Este trabalho teve como objetivo preparar e caracterizar extratos secos de H. pluvialis pela técnica de secagem em torre de aspersão, avaliando o efeito do emprego de adjuvantes farmacêuticos e dos parâmetros de secagem sobre as características finais dos extratos secos. Além disso, as atividades antioxidante e citotóxica dos carotenoides obtidos a partir dos extratos secos foram avaliadas. Quando a extração dos carotenoides a partir da biomassa da microalga foi avaliada, altos valores de rendimento que variaram entre 87,8% e 94,6% foram obtidos. Após a extração e a secagem por pulverização não foram observadas diferenças na morfologia das partículas e os valores de densidade aparente e compactada não parecem ser afetados quando as diferentes condições de secagem por pulverização foram testadas. Observou-se que o aumento da temperatura e concentração do adjuvante de secagem proporcionou redução do teor de carotenoides totais. Os valores da atividade antioxidante dos extratos de carotenoides variaram entre 55,78 e 77,83%, com os menores valores verificados para os extratos secos preparados com a maior temperatura de entrada. A avaliação da atividade antiproliferativa dos extratos de carotenoides demonstrou que as maiores concentrações testadas reduziram de 66,58 e 82,91% a viabilidade de células de melanoma murino B16F10. Assim, o conjunto de resultados demonstrou que a obtenção de extratos secos a partir da biomassa de Haematococcus pluvialis visando a produção de matérias-primas farmacêuticas utilizando a secagem em torre de aspersão (spray dryer) é promissor especialmente, com altos valores de carotenoides totais e sem perda significativa da atividade antioxidante.

ABSTRACT Carotenoids comprise a class of more than 600 natural pigments whose biological potential is related to their antioxidant activity, regulation of cell growth, modulation of the immune response and anti-inflammatory activity. Haematococcus pluvialis is a green microalga known to synthesize and accumulate large amounts of carotenoids, among them astaxanthin. The objective of this work was to prepare and characterize dry extracts of H. pluvialis by spray drying technique, evaluating the effect of the use of pharmaceutical adjuvants and the drying parameters on the final characteristics of dry extracts. In addition, the antioxidant and cytotoxic activities of the carotenoids obtained from the dried extracts were evaluated. When the extraction of the carotenoids from the microalgae biomass was evaluated, high yield values ranging from 87.8% to 94.6% were obtained. After extraction and spray drying no differences in particle morphology were observed and bulk density and compacted values did not appear to be affected when different spray drying conditions were tested. It was observed that increasing the temperature and concentration of the drying aid provided a reduction in the total carotenoid content. The antioxidant activity values of carotenoid extracts varied between 55.78 and 77.83%, with the lowest values observed for the dry extracts prepared with the highest inlet temperature. The evaluation of the antiproliferative activity of carotenoid extracts showed that the highest concentrations tested reduced the viability of B16F10 murine melanoma cells from 66.58 and 82.91%. Thus, the results set showed that the extraction of dry extracts from the biomass of Haematococcus pluvialis for the production of pharmaceutical raw materials using spray drying is especially promising, with high total carotenoid values, and without significant loss of antioxidant activity.

Neste estudo, nanocarreadores lipídicos foram preparados a partir do triestearato de glicerila e óleo de rícino em diferentes proporções pela técnica de difusão do solvente a quente. Estearato de PEG-660 ou Poloxamer 188 e lecitina de soja foram usados como surfactante e cossurfactante, respectivamente. Características estruturais e físico-químicas das partículas foram investigadas por meio de espalhamento de luz dinâmico (DLS), calorimetria exploratória diferencial (DSC), espalhamento de raios X a altos ângulos (WAXS), microscopia de força atômica (AFM) e microscopia eletrônica de transmissão (TEM e cryo-TEM). Aanálise por DLS indicou que partículas menores foram obtidas quando o lipídio líquido foi usado sozinho para obter as nanoemulsões (NEs). Técnicas microscópicas (TEM e cryo-TEM) mostraram que as NEs apresentaram formas esféricas, enquanto as nanopartículas lipídicas sólidas (NLSs) e os carreadores lipídicos nanoestruturados (CLNs) apresentaram formas mais complexas. As NLSs exibiram estrutura cristalina lamelar, enquanto os CLNs exibiram uma estrutura mista composta de fase cristalina lamelar em contato com compartimento oleoso. Estes experimentos contribuem para um melhor entendimento da capacidade de incorporação e liberação de fármacos destes nanocarreadores.

In this study, drug delivery nanocarriers based on glyceryl tristearate and castor oil at different ratios were prepared by the hot solvent diffusion method. PEG 660-stearate or Poloxamer 188 and soybean lecithin were used as surfactant and co-surfactant, respectively. Structural and physicochemical characteristics of the particles were investigated by means of dynamic light scattering (DLS), differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXS), atomic force microscopy (AFM) and transmission electron microscopy (TEM and cryo-TEM). DLS data indicated that smaller particles were obtained when the liquid lipid was used alone to prepare nanoemulsions (NEs). TEM and cryo-TEM images showed that NEs presented spherical particles, whereas solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) presented more complex shapes. SLNs exhibited lamellar crystal structure, while NLCs displayed a hybrid structure composed of a lamellar crystalline phase in contact with a liquid oil compartment. These experiments contribute to a better understanding of the structure and release performance of these drug carrier systems.

Solid lipid nanoparticles (SLN), nanoemulsions (NE), and microemulsions (ME) were prepared by the hot solvent diffusion method, using tristearin or castor oil as oily phase, and soy lecithin and Solutol HS 15 as surfactants. Mean particle sizes ranged from 20 to 215 nm and negative zeta potentials were obtained for all nanocarriers. A HPLC method used to determine resveratrol was specific, linear, exact and precise. The entrapment efficiency was high for all formulations. However, resveratrol content was significantly varied among the lipid nanocarriers. Lipid nanocarrier containing hydrogels exhibiting pseudoplastic behavior were obtained after incorporation of hydroxyethylcellulose in the colloidal dispersions.

Um método fluorimétrico simples, rápido e sensível foi desenvolvido e validado para quantificação da curcumina em suspensões de nanocápsulas lipídicas e poliméricas, usando acetonitrila como solvente. Os comprimentos de onda de excitação e emissão foram 397 nm e 508 nm, respectivamente. Nas condições testadas, a curva de calibração demonstrou-se linear na faixa de 0,1 a 0,6 µg/mL, exibindo coeficiente de correlação de 0,9982. Os limites de detecção e quantificação foram 0,03 e 0,10 µg/mL, respectivamente. Os resultados da validação confirmaram que o método desenvolvido é específico, linear, exato e preciso para o uso proposto. O presente método foi aplicado com sucesso para a avaliação do teor de curcumina nas suspensões de nanocápsulas lipídicas e poliméricas durante o estágio inicial do desenvolvimento da formulação.

A simple, rapid, and sensitive fluorimetric method was developed and validated to quantify curcumin in lipid and polymeric nanocapsule suspensions, using acetonitrile as a solvent. The excitation and emission wavelengths were set at 397 nm and 508 nm, respectively. The calibration graph was linear from 0.1 to 0.6 µg/mL with a correlation coefficient of 0.9982. The detection and quantitation limits were 0.03 and 0.10 µg/mL, respectively. The validation results confirmed that the developed method is specific, linear, accurate, and precise for its intended use. The current method was successfully applied to the evaluation of curcumin content in lipid and polymeric nanocapsule suspensions during the early stage of formulation development.

O desenvolvimento de microesferas de carbamazepina (CBZ) de liberação prolongada tem sido realizado, empregando-se a técnica de emulsificação/evaporação do solvente e o acetobutirato de celulose (ABC70) para a obtenção da matriz polimérica. Buscando modular a velocidade de liberação do fármaco, a adição de polietilenoglicóis na fase interna da emulsão foi testada. Quando comparados com as microesferas preparadas unicamente com ABC70, o teor e a eficiência de encapsulação da CBZ, estimados após análise por CLAE, foram drasticamente reduzidos com a adição de PEG4000. Entretanto, a adição de PEG 1500 perfazendo 10% da massa total de polímero não pareceu alterar o teor de CBZ, demonstrando que o peso molecular do PEG influencia a encapsulação da CBZ. Partículas mais porosas foram visualizadas por MEV, quando o PEG1500 ou 4000 foram adicionados. Entretanto, a perda da forma esférica foi observada quando uma mistura de ABC70:PEG 4000 1:1 foi empregada. A adição de polietilenoglicóis não pareceu afetar o diâmetro médio das microesferas. A redução na encapsulação da CBZ foi associada à extração do PEG durante a etapa de evaporação do solvente e a sua capacidade de dissolvê-la na fase externa da emulsão. O controle do desenvolvimento da presença de poros, pelo ajuste da concentração e do peso molecular do PEG, pode ser útil na modulação do perfil de liberação do fármaco.

With the aim of obtaining carbamazepine (CBZ) prolonged release dosage forms, cellulose acetate butyrate (CAB70) microspheres have been prepared by the emulsion/solvent evaporation method. In order to modulate the CBZ release, the addition of polyethylene glycols (PEG) in the internal phase of the emulsion was carried out. When compared with microspheres prepared only from CAB70, the encapsulation efficiency and the CBZ content were drastically reduced by the PEG 4000 addition. On the other hand, the incorporation of 10% (w/w) of PEG1500 did not affect the drug content in the microspheres. Most porous particles werw observed by SEM when PEG 1500 or 4000 was added to the formulations, however the lost of the spherical shape of the particles was verified when an ABC70:PEG 4000 1:1 mixture was used to prepare the microspheres. The addition of PEGs did not appear to affect the mean diameter of the particles. The decrease of the CBZ content was related to the PEG extraction during the solvent evaporation step and to its ability to dissolve the CBZ in the external phase of the emulsion. The porosity development control, by adjusting the amount or the molecular weight of PEG, can be useful in the drug release from microparticles.