Synthesis and Physicochemical Stability of a Copaiba Balsam Oil (Copaifera sp.) Nanoemulsion and Prospecting of Toxicological Effects on the Nematode Caenorhabditis elegans.

Nanoemulsions are dispersions of oil-in-water (O/W) and water-in-oil (W/O) immiscible liquids. Thus, our main goal was to formulate a nanoemulsion with low surfactant concentrations and outstanding stability using Copaiba balsam oil (Copaifera sp.). The high-energy cavitation homogenization with low Tween 80 levels was employed. Then, electrophoretic and physical mobility properties were assessed, in addition to a one- and two-year physicochemical characterization studies assessment. Copaiba balsam oil and nanoemulsions obtained caryophyllene as a major constituent. The nanoemulsions stored at 4 ± 2 °C exhibited better physical stability. Two years after formulation, the nanoemulsion showed a reduction in the particle size. The size underwent changes in gastric, intestinal, and blood pH, and the PdI was not changed. In FTIR, characteristic bands of sesquiterpenes and overlapping bands were detected. When subjected to freezing and heating cycles, nanoemulsions did not show macroscopic changes in higher concentrations. Nanoemulsions subjected to centrifuge force by 1000 rpm do not show macroscopic instability and phase inversion or destabilization characteristics when diluted. Therefore, the nanoemulsion showed stability for long-term storage. The nematode Caenorhabditis elegans was used to assess the potential toxicity of nanoemulsions. The nanoemulsion did not cause toxicity in the animal model, except in the highest concentration tested, which decreased the defecation cycle interval and body length. The toxicity and stability outcomes reinforce the nanoemulsions' potential for future studies to explore pharmacological mechanisms in superior experimental designs.

ConA-Coated Liposomes as a System to Delivery ß-Lapachone to Breast Cancer Cells.

BACKGROUND: Target treatment using site-specific nanosystems is a hot topic for treating several diseases, especially cancer. OBJECTIVE: The study was set out to develop site-specific liposomes using ConcanavalinA (ConA) to target ß- lapachone(ß-lap) to human breast cancer cells. METHODS: Liposomes were prepared and characterized according to diameter size, zeta potential, ConA conjugation(%) and ß-lap encapsulation efficiency (%). Isothermal Titration Calorimetry evaluated the binding energy between the biomolecules, which compose of the liposomes. ConA avidity was assessed before and after conjugation. Cytotoxicity was evaluated, and fluorescence microscopy was performed to investigate the influence of ConA influenced on MCF-7 uptake. RESULTS: Uncoated and ConA-coated liposomes presented size, and zeta potential values from 97.46 ± 2.01 to 152.23 ± 2.73 nm, and -6.83 ± 0.28 to -17.23 ±0.64 mV, respectively. Both ConA conjugation and ß-lap encapsulation efficiency were approximately 100%. The favorable and spontaneous process confirmed the binding between ConA and the lipid. Hemagglutination assay confirmed ConA avidity once Lipo-ConA and Lipo-PEG-ConA were able to hemagglutinate the red blood cells at 128-1 and 256-1, respectively. Lipo-ConA was not cytotoxic, and the site-specific liposomes presented the highest toxicity. ConA-coated liposomes were more internalized by MCF7 than uncoated-liposomes. CONCLUSION: Therefore, the presence of ConA on the surface of liposomes influenced MCF7 uptake, in that way could be used as a promising site-specific system to target ß-lap to cancer cells.

Ocular delivery of moxifloxacin-loaded liposomes / Perfil de liberação ocular de lipossomas contendo moxifloxacino

ABSTRACT Purpose: To determine the release profile of moxifloxacin encapsulated in liposomes in the aqueous humor as a controlled release system for intracameral application. Methods: Liposomes containing moxifloxacin were obtained using the lipid film hydration method and were characterized by particle size and encapsulation efficiency. Female rabbits were used for the in vivo profile release study. Liposomes containing moxifloxacin was injected into the anterior chamber of the right eye of each animal. The rabbits were divided into five groups, and a sample of aqueous humor was collected 2, 4, 8, 24, and 48 h after administration of liposomes containing moxifloxacin administration. Moxifloxacin concentrations in the aqueous humor were analyzed using high-performance liquid chromatography. Results: The average size of the liposomes containing moxifloxacin was 60.5 ± 0.72 nm with a particle size distribution of 0.307. The encapsulation efficiency of moxifloxacin in liposomes was 92.24 ± 0.24%. The results of an in vivo release study of liposomes containing moxifloxacin, showed that the maximum moxifloxacin concentration was achieved within the first 2 h after administration (5.27 ± 1.09 mg/mL) and was followed by a decrease in intracameral concentration (0.35 ± 0.05 mg/mL) until the 24 h mark. Conclusions: The in vivo experiments resulted in liposomes containing moxifloxacin that were homogenous in size and exhibited high drug encapsulation efficiency. The results indicate that liposomes containing moxifloxacin offers a satisfactory aqueous humor release profile after intracameral application.

RESUMO Objetivo: Determinar o perfil de liberação, no humor aquoso, de moxifloxacino encapsulado em lipossomas como um sistema de liberação controlada para aplicação intracameral. Métodos: Lipossomas contendo moxifloxacino foram obtidos através do método de hidratação do filme lipídico e caracterizados por tamanho da partícula e eficiência de encapsulação. Utilizaram-se coelhos fêmeas foram para o estudo do perfil de liberação in vivo. Lipossomas contendo moxifloxacino foram injetados na câmara anterior do olho direito de cada animal. Os coelhos foram divididos em cinco grupos, e uma amostra de humor aquoso foi coletada 2, 4, 8, 24 e 48 h após a administração de lipossomas contendo moxifloxacino. As concentrações de moxifloxacino no humor aquoso foram analisadas usando cromatografia líquida de alta eficiência. Resultados: O tamanho médio dos lipossomas contendo moxifloxacino foi de 60,5 ± 0,72 nm com uma distribuição de tamanho de partícula de 0,307. A eficiência de encapsulação de moxifloxacino nos lipossomas foi de 92,24 ± 0,24. Os resultados de um estudo de liberação in vivo de lipossomas contendo moxifloxacino, mostraram que a concentração máxima de moxifloxacino foi atingida dentro das primeiras 2 h após sua administração (5,27 ± 1,09 mg/mL) e foi seguida de um decréscimo na concentração intracameral (0,35 ± 0,05 mg/mL) até a marca de 24 h. Conclusão: Os experimentos in vivo resultaram em lipossomas contendo moxifloxacino que eram homogêneos em tamanho e exibiam alta eficiência de encapsulação do fármaco. Os resultados indicam que lipossomas contendo moxifloxacino oferecem um perfil de liberação de humor aquoso satisfatório após a aplicação intracameral.

Ocular delivery of moxifloxacin-loaded liposomes.

PURPOSE: To determine the release profile of moxifloxacin encapsulated in liposomes in the aqueous humor as a controlled release system for intracameral application. METHODS: Liposomes containing moxifloxacin were obtained using the lipid film hydration method and were characterized by particle size and encapsulation efficiency. Female rabbits were used for the in vivo profile release study. Liposomes containing moxifloxacin was injected into the anterior chamber of the right eye of each animal. The rabbits were divided into five groups, and a sample of aqueous humor was collected 2, 4, 8, 24, and 48 h after administration of liposomes containing moxifloxacin administration. Moxifloxacin concentrations in the aqueous humor were analyzed using high-performance liquid chromatography. RESULTS: The average size of the liposomes containing moxifloxacin was 60.5 ± 0.72 nm with a particle size distribution of 0.307. The encapsulation efficiency of moxifloxacin in liposomes was 92.24 ± 0.24%. The results of an in vivo release study of liposomes containing moxifloxacin, showed that the maximum moxifloxacin concentration was achieved within the first 2 h after administration (5.27 ± 1.09 mg/mL) and was followed by a decrease in intracameral concentration (0.35 ± 0.05 mg/mL) until the 24 h mark. CONCLUSIONS: The in vivo experiments resulted in liposomes containing moxifloxacin that were homogenous in size and exhibited high drug encapsulation efficiency. The results indicate that liposomes containing moxifloxacin offers a satisfactory aqueous humor release profile after intracameral application.

Antifungal activity of a liposomal itraconazole formulation in experimental Aspergillus flavus keratitis with endophthalmitis.

The aim of this study was to assess the efficacy of topical application of a liposomal formulation of itraconazole for the treatment of experimental keratitis with endophthalmitis caused by Aspergillus flavus. The liposomes were obtained by the lipid film hydration method followed by sonication. Adult female Wistar rats (weighing 200-220 g) were immunosuppressed by intraperitoneal injection of 150 mg/kg of cyclophosphamide 3 days before infection by exposure to the fungus A. flavus (10(7) spores/ml). Forty-eight hours later, the animals were treated with the liposomal formulation. For comparison, one group of animals (n = 6) was treated with the same drug not encapsulated. At the end of the experiment, the animals were evaluated for clinical signs and number of colony forming units (CFU/g), along with direct microscopic examination. The results indicated that the liposomal formulation of itraconazole has better antifungal activity than the unencapsulated drug in the treatment of fungal keratitis with endophthalmitis caused experimentally by A. flavus in Wistar rats.

Desenvolvimento e validação de método analítico em CLAE-UV para a quantificação de ácido retinóico em microcápsulas de alginato e quitosana / Development and validation of analytical method on HPLC-UV for quantification of retinoic acid in microcapsules of alginate and chitosan

O ácido retinóico (AR) tem sido utilizado para o tratamento de acne severa, rugas, estrias e celulite, no entanto, provoca irritação na pele e sofre rápida degradação quando exposto à luz e ao calor. Métodos analíticos rápidos para quantificação do AR são, portanto, necessários para ensaios de cinética de liberação in vitro. Nesse contexto, o objetivo deste trabalho foi desenvolver e validar um método rápido e sensível para o doseamento do AR em microcápsulas de alginato/quitosana contendo óleo de babaçu dispersas em gel natrosol® por cromatografia líquida de alta eficiência associada à espectroscopia UV e aplicá-lo na avaliação do perfil de liberação in vitro dessas formulações. As análises foram realizadas em modo isocrático utilizando coluna C18 de fase reversa 150 x 4,6 mm (5 μm) com detecção a 350 nm. A fase móvel foi constituída de metanol e ácido acético 1 por cento (85:15 v/v) com vazão de 1,8 mL/minuto. A faixa de linearidade do método foi de 0,5 a 60 μg/mL (r² = 0,999). O método validado mostrou-se sensível, específico, exato, preciso, de baixo custo e o tempo de retenção do AR foi de 5,8 ± 0,4 minutos sendo, desta forma, mais rápido do que os relatados na literatura.

Retinoic acid (RA) has been used in the treatment of severe acne, wrinkles and cellulite. However, it induces skin irritation and rapidly suffers degradation under light and high temperate exposure. Rapid analytical methods to quantify retinoic acid are therefore mandatory for in vitro drug release studies. In this framework, the aim of this study was to develop and validate a rapid and responsive method to quantify the RA in microcapsules of chitosan and alginate containing babassu oil dispersed in natrosol® hydrogel using high performance liquid chromatography (HPLC). Furthermore this method was used to quantify in vitro release kinetics of RA from microcapsules. The analyses have been carried through an isocratic HPLC-UV method using a reversed phase 150 x 4.6 mm C18 (5μm) column, a mobile phase constituted of methanol and 1 percent acetic acid (85:15) at a flow rate of 1.8 mL/min and detection at 350 nm. The linearity range was 0.5-60 μg/mL (r² = 0.999). The validated HPLC-UV method was responsive, specific, accurate, precise, and economic and the RA retention time was 5.8 ± 0.4 minutes, being therefore, faster than that previously reported.

Validação de método analítico espectrofotométrico UV para determinação de ácido úsnico em lipossomas / Validation of a UV-spectrophotometric analytical method for the determination of usnic acid in liposomes

O ácido úsnico (AU) é um composto de origem liquênica e tem demonstrado importantes atividades biológicas, tais como: antitumoral, antimicrobiano, antiviral, antiproliferativo e antiinflamatório. Os lipossomas são vesículas lipídicas contendo espaço aquoso interno e têm sido utilizados como carreadores coloidais de fármacos, principalmente na terapêutica de câncer e infecções bacterianas e fúngicas. O objetivo desse trabalho foidesenvolver e validar um método espectrofotométrico UV para determinação de ácido úsnico em lipossomas. Os parâmetros de validação linearidade, precisão, exatidão, robustez, limites de detecção e quantificação foram determinados segundo diretrizes internacionais de padronização e Farmacopéia Americana. A faixa de linearidade foi de 3 a 15 μg.mL-1, a equação de regressão:absorbância = 0,070 x [AU] (μg.mL-1) + 0,013 e r = 0,9997. A repetibilidade (coeficiente de variação) do método foi 1,96% e a precisão intermediária indicou que a diferença entre as médiasfoi estatisticamente insignificante (P < 0,05). A exatidão revelou média percentual de recuperação de 100,4%. O método foi robusto apesar da variação de temperatura e solventes. Os limites de detecção e quantificação do ácido úsnico foram de 0,34 e 1,13 μg.mL-1, respectivamente. O doseamento do ácido úsnico nos lipossomas foi de 96,8% (± 0,2). O método proposto é exato, preciso e reprodutível sendo capaz de quantificar o ácido úsnicoem matéria-prima e em preparações farmacêuticas.

The secondary lichen metabolite usnic acid [2,6-diacetyl- 7,9-dihydroxy-8,9b-dimethyl-1,3(2H,9bH)-dibenzofuran]has demonstrated pharmacological potential activities such as antitumor, antimicrobial, antiviral, antiproliferative, and anti-inflammatory. Liposomes arevesicles composed of phospholipid bilayers surrounding aqueous compartments and they have been used as colloidal drug carriers. The aim of this study was to develop and validate a quantitative UV spectrophotometric method for determination of usnicacid in liposomal formulations. The validation parameters were assessed according to The International Conference on Harmonization (ICH) and American Pharmacopoeia guidelines. The linearity range was of 3-15 μg.mL-1,regression equation: absorbance = 0.070 x UA concentration (μg.mL-1) + 0.013, and r = 0.9997. The repeatability (relative standard deviation) of the method was 1.96% and intermediate precision indicated that the difference among mean was statistically insignificant (P < 0.05). The accuracy revealed a mean percentage recovery of 100.4% of usnic acid. The method was robust for the variation of temperature and solvent. The detection and quantization limits were found to be 0.34 and 1.13 μg.mL-1, respectively. The content of usnic acid in liposomes was of 96.8% (± 0.2). The proposed method is accurate, precise and reproducible for estimation of usnic acid as raw material and in pharmaceutical dosage forms such as liposomes.

Uma revisão das atividades biológicas da trans-desidrocrotonina, um produto natural obtido de Croton cajucara / A review of the biologic activities of trans-dehydrocrotonin, a natural product obtained from Croton cajucara

Croton cajucara Beth (Euphorbiaceae) uma espécie medicinal nativa da região Amazônica do Brasil, onde é vulgarmente conhecida como 'sacaca', representa um recurso terapêutico eficaz no tratamento e cura de várias doenças. O metabólito majoritário trans-desidrocrotonina (DCTN), isolado das cascas do caule desta planta, encontra-se correlacionado com grande parte das propriedades medicinais da sacaca. Este artigo de revisão, descreve os resultados fitoquímicos e farmacológicos que foram realizados com o diterpeno do tipo clerodano DCTN, bem como seus derivados semi-sintéticos. Adicionalmente, apresenta perspectivas para a biodisponibilização deste protótipo de fármaco em nanosistemas.

Croton cajucara Beth (Euphorbiaceae) is a plant found in the Amazonian Region of North Brazil, where it is popularly known as sacaca. The major secondary metabolite, trans-dehydrocrotonin (DCTN) a clerodane-type diterpene, isolated from the stem bark is a chief bioactive compound of Croton cajucara. This review describes results of extensive pharmacological studies of DCTN, as well as its semi-synthetic derivatives, and also presents insights into the use of DCTN as a therapeutic agent and some potential advantages of its incorporation in drug delivery systems.

Lipossomas e suas aplicações terapêuticas: estado da arte / Liposomes and their therapeutic: state of art applications

Lipossomas são vesículas constituídas de uma ou mais bicamadas fosfolipídicas orientadas concentricamente em torno de um compartimento aquoso e servem como carreadores de fármacos, biomoléculas ou agentes de diagnóstico. A estabilidade dos lipossomas pode ser afetada por fatores químicos, físicos e biológicos. Após administração intravenosa, lipossomas convencionais são rapidamente capturados pelo sistema fagocitário mononuclear. Para evitar essa captura, lipossomas furtivos foram desenvolvidos, os quais apresentam a superfície modificada com componentes hidrofílicos. Para permitir a liberação seletiva do fármaco nos sítios alvos, ligantes de reconhecimento específico são conjugados na superfície de lipossomas. Em geral, os métodos de preparação de lipossomas incluem hidratação de um filme lipídico seguida de sonicação ou extrusão para redução do tamanho das vesículas. Os lipossomas são caracterizados quanto ao tamanho e composição química das vesículas e conteúdo do material encapsulado. Nesta revisão, constata-se que os lipossomas oferecem maior eficácia e segurança com relação aos tratamentos convencionais. Apesar de algumas formulações lipossomais serem comercializadas desde os anos 1980 para tratamento de infecções fúngicas sistêmicas e do câncer, problemas de ordem tecnológica e biológica fazem com que os lipossomas sejam ainda extensivamente estudados para desenvolvimento de formulações estáveis no organismo visando à terapia de várias doenças, principalmente do câncer.

Liposomes are vesicles that consist of one or more concentric phospholipidic bilayers organized around an aqueous inner compartment. They are carriers of drugs, biomolecules and diagnostic agents. The stability of liposomes can be influenced by chemical or physical factors. Once injected in the circulatory system, conventional liposomes suffer uptake by the mononuclear phagocytic system. To avoid such a capture, non-conventional or Stealth® liposomes were developed, which are coated by hydrophilic components. Specific ligand had been incorporated in their surface so as to control the drug release and selectivity, thereby originating the targeted liposomes. In general, all preparation methods of liposomes include the hydration of lipidic film followed by sonication or extrusion to reduce the mean size of vesicles. After preparation, the vesicles are characterized by size, chemical constitution, and amount of encapsulated material. In this review it is shown that the liposomes offer effectiveness and safety in comparison with many conventional treatments. In spite of the existence of a few liposomal formulations available since early 80's, which are used for the treatment of systemic fungal infections and cancer, many technological and biological issues remain as a challenge. In this scenario, liposomes have extensively been studied in order to improve their in vivo stability in the treatment of several diseases, including cancer.

Avaliação farmacocinética de comprimidos contendo lamivudina e zidovudina em plasma humano / Pharmacokinetic evaluation of lamivudine and zidovudine tablets in human plasma

Este estudo se propõe a avaliar o perfil farmacocinético de comprimidos contendo lamivudina e zidovudina associados, produzidos pelo Laboratório Farmacêutico do Estado de Pernambuco ­ LAFEPE. O medicamento foi administrado em 10 voluntários sadios e foram observadas as concentrações plasmáticas dos dois anti-retrovirais durante 12 horas. A partir das concentrações plasmáticas foi possível encontrar os parâmetros farmacocinéticos de ambas os fármacos através de cálculos estatísticos. Os resultados obtidos foram comparados com aqueles resultantes de experimentos realizados por outros autores descritos neste trabalho, em que verificou não haver diferenças significativas entre os valores encontrados e os descritos na literatura e que o fato dos anti-retrovirais estarem associados na mesma formulação não modificou o perfil cinético de nenhuma das substâncias

Síntese e atividade biológica de novas tiossemicarbazonas / Synthesis and biological activity of new thiosemicarbazones

Este trabalho descreve a síntese e avaliaçäo estrutural de nove tiossemicarbazonas, obtidas pela condensaçäo de ariltioacetaldeídos e artiopropanonas substituídas com cloridrato de tiossemicarbazida. Estes novos compostos foram testados in vitro pelo fitoteste Lepidium sativum. Todos eles apresentaram atividade inibidora do crescimento celular (pI50) superior àquela de 5-fluoruacila, composto anticancerígeno, utilizado como referência.