Navegando por Palavras-chave "Solubility"
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- ItemSomente MetadadadosCrystal growth of progesterone metastable and stable polymorphs by polymer induced herteronucleation (pihn) method(Wiley-v c h verlag gmbh, 2016) Araya-Sibaja, Andrea Mariela; Soldi, Valdir; Maduro de Campos, Carlos Eduardo; Cardoso, Simone Goncalves; Cuffini, Silvia Lucia [UNIFESP]The selective crystallization of progesterone polymorphs prepared by Polymer-Induced Heteronucleation (PIHn) method was investigated. Polyvinyl alcohol (PVA), hydroxypropyl methylcellulose (HPMC), dextran, gelatin, polyisoprene (PI), and acrylonitrile/butadiene copolymer (NBR) were used as heteronucleants. Crystallizations were conducted from 0.5,10 and 40 mg mL(-1) solutions in chloroform at room temperature by solvent evaporation. The samples were characterized by X-ray powder diffraction, differential scanning calorimetry, infrared spectroscopy and scanning electron microscopy. Form 2 was obtained from 0.5 mg mL(-1) solution in almost all polymers. A mixture of both poly morphs crystallized from the three concentrations on gelatine
- ItemSomente MetadadadosImprovement of carbon dioxide absorption by mixing poly(ethylene glycol) dimethyl ether with ammonium-based ionic liquids(Elsevier Science Bv, 2018) Lepre, L. F.; Pison, L.; Siqueira, L. J. A. [UNIFESP]; Ando, R. A.; Gomes, M. F. CostaMixtures of the ionic liquid butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, [N-4111][NTf2] with poly(ethylene oxide) polymers, PEO, of different molecular weights were investigated for CO2 capture. The liquid mixtures are close to ideal in terms of their volumetric properties but their enthalpies of mixing are negative, decreasing when the size of the polymer chain increases and being close to those observed for associative compounds mixed with ionic liquids (Delta H-mix = -7 kJ mol(-1) for [N-4111][NTf2] + PEO1000 at 318 K). The favorable interactions between the polymer and the ionic liquid could be related to the dynamic properties of the mixtures, especially for mixtures of polymers of longer chain sizes which have a higher viscosity than that of the pure mixture components. Raman spectroscopy confirmed an association between the cation of the ionic liquid and the polymers that probably surround the cation and thus contribute to slow the dynamics of the mixtures. The increase of the carbon dioxide absorption with the increase of the polymer mole fraction composition in the liquid mixture is explained by the more favorable interactions between the gas and the polymer as evidenced by the analysis of the thermodynamic properties of solvation. (C) 2017 Elsevier B.V. All rights reserved.
- ItemSomente MetadadadosInclusion complex and nanoclusters of cyclodextrin to increase the solubility and efficacy of albendazole(Springer, 2018) Pacheco, P. A.; Rodrigues, Letícia Norma Carpentieri [UNIFESP]; Ferreira, J. F. S.; Gomes, A. C. P.; Verissimo, C. J.; Louvandini, H.; Costa, R. L. D.; Katiki, L. M.Albendazole (ABZ), a benzimidazole widely used to control gastrointestinal parasites, is poorly soluble in water, resulting in variable and incomplete bioavailability. This has favored the appearance ABZ-resistant nematodes and, consequently, an increase in its clinical ineffectiveness. Among the pharmaceutical techniques developed to increase drug efficacy, cyclodextrins (CDs) and other polymers have been extensively used with water-insoluble pharmaceutical drugs to increase their solubility and availability. Our objective was to prepare ABZ formulations, including beta-cyclodextrin (beta CD) or hydroxypropyl-beta-cyclodextrin (HP beta CD), associated or not to the water-soluble polymer polyvinylpyrrolidone (PVP). These formulations had their solubility and anthelmintic effect both evaluated in vitro. Also, their anthelmintic efficacy was evaluated in lambs naturally infected with gastrointestinal nematodes (GIN) through the fecal egg count (FEC) reduction test. In vitro, the complex ABZ/HP beta CD had higher solubility than ABZ/beta CD. The addition of PVP to the complexes increased solubility and dissolution rates more effectively for ABZ/HP beta CD than for ABZ/beta CD. In vivo, 48 lambs naturally infected with GIN were divided into six experimental groups: control, ABZ, ABZ/beta CD, ABZ/beta CD-PVP, ABZ/HP beta CD, and ABZ/HP beta CD-PVP. Each treated animal received 10 mg/kg of body weight (based on the ABZ dose) for three consecutive days. After 10 days of the last administered dose, treatment efficacy was calculated. The efficacy values were as follows: ABZ (70.33%), ABZ/beta CD (85.33%), ABZ/beta CD-PVP (82.86%), ABZ/HP beta CD (78.37%), and ABZ/HP beta CD-PVP (43.79%). In vitro, ABZ/HP beta CD and ABZ/HP beta CD-PVP had high solubility and dissolution rates. In vivo, although the efficacies of ABZ/beta CD, ABZ/beta CD-PVP, and ABZ/HP beta CD increased slightly when compared to pure ABZ, this increase was not significant (P > 0.05).
- ItemAcesso aberto (Open Access)Microemulsões como veículo de drogas para administração ocular tópica(Conselho Brasileiro de Oftalmologia, 2003-06-01) Cunha Júnior, Armando Da Silva; Fialho, Sílvia Ligório; Carneiro, Luciana Barbosa [UNIFESP]; Oréfice, Fernando; Universidade Federal de Minas Gerais Faculdade de Farmácia; Universidade Federal de São Paulo (UNIFESP); Universidade Federal de Minas Gerais Hospital das Clínicas Serviço de Uveítes; Universidade Federal de Minas GeraisThe conventional ophthalmic dosage forms are relatively simple: usually, water-soluble drugs are delivered in aqueous solution and water-insoluble drugs are prepared as suspensions or ointments. However, these delivery systems currently used present very low corneal bioavailability, systemic exposure because of nasolacrimal drainage and lack of efficiency in the posterior segment of ocular tissue. Recent research efforts have focused on the development of new ophthalmic drug delivery systems. As a result of these efforts, microemulsions are promising dosage forms for ocular use. These delivery systems are dispersions of water and oil that require surfactant and co-surfactant agents in order to stabilize the interfacial area. The microemulsions have a transparent appearance, thermodynamic stability and small droplet size of the dispersed fase (<1,0 mm), providing them with the capacity of being sterilized by filtration. Furthermore, these systems offer additional advantages that include: low viscosity, great ability as drug delivery vehicles, widened properties as absorption promoters and easiness of preparation, which do not require much energy and the use of special equipments. In this review, we present the technology and some preliminary studies of microemulsions in relation to ocular drug delivery systems.
- ItemAcesso aberto (Open Access)Preparo de misturas de celecoxibe e ciclodextrina para o aumento da solubilidade do fármaco em meio aquoso(Universidade Federal de São Paulo, 2023-01-04) Escudeiro, Júlia de Souza [UNIFESP]; Andréo Filho, Newton [UNIFESP]; http://lattes.cnpq.br/4715398927727906O celecoxibe é um anti-inflamatório não esteroide (AINE), classificado como fármaco de classe II, segundo o Sistema de Classificação Biofarmacêutica (SCB), por apresentar baixa solubilidade e alta permeabilidade. A grande utilização de AINEs consagra o grupo de medicamentos mais difundido, sendo uma realidade em todo o mundo. O tema interessa diversos setores e há demanda projetada do setor de pesquisa acadêmica e de indústrias farmacêuticas. É sabido que a solubilidade de um medicamento de via oral estabelece condição prévia de absorção e, assim, se constitui um dos mais importantes impedimentos à eficácia. O presente trabalho, buscou aumentar a solubilidade do celecoxibe, esperando que o mesmo possa estar mais disponível para ser absorvido quando administrado oralmente, possibilitando a administração de doses menores. Testou-se em diferentes pHs a solubilidade do CLX (celecoxibe) tanto em HCl 0,1 mol/L, como em soluções tampão acetato pH 4,5, tampão fosfato pH 6,8 e 7,4 e foi entendido que sua solubilidade é aumentada, conforme mais ácido for o pH. Para fim de obtenção do complexo de inclusão, preparou-se uma amostra proveniente da mistura de um solução alcoólica de celecoxibe e solução hidroalcoólica de βCD e também de HPβCD. As amostras ficaram em repouso, gerando duas fases: a sólida precipitada e a líquida, posteriormente separadas por um processo de filtração. Na fase sólida de cada amostra, foi realizada a evaporação do solvente em estufa e as porções líquidas foram congeladas e liofilizadas. Para cada amostra final obtida, preparou-se alíquotas diluídas em álcool absoluto. Posteriormente, utilizando-se o espectrofotômetro de UV-vis, foram quantificadas em comprimento de onda de 253 nm e através disso calculou-se a concentração de celecoxibe dissolvida em cada uma das quatro amostras, bem como o teor do fármaco, o qual se mostrou mais significativo para a porção sólida contendo CLX:βCD. Em seguida, após a construção da curva analítica de celecoxibe em HCl 0,1 mol/L, se fez ensaio de solubilidade dessa porção mais promissora neste meio. Utilizando-se o espectrofotômetro de UV-vis, foi quantificada em comprimento de onda de 248 nm, permitindo calcular um aumento de solubilidade de 632,47%, em meio ácido (pH 1,20).