Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Chem Commun (Camb) ; 55(23): 3410-3413, 2019 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-30839031

RESUMO

Solvated lithium closo-dodecaborate, Li2B12H12 with tetrahydrofuran and acetonitrile, show unexpected melting below 150 °C. This feature has been explored to melt-infiltrate Li2B12H12 in a nanoporous SiO2 scaffold. The ionic conductivity of Li2B12H12·xACN reaches 0.08 mS cm-1 in the liquid state at 150 °C making them suitable as battery electrolytes.

2.
AAPS PharmSciTech ; 19(7): 3009-3018, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30062539

RESUMO

When we administered orally a mixture of the anti-diabetic drug, gliclazide (G) and a primary bile acid, they exerted a hypoglycemic effect in a rat model of type 1 diabetes (T1D), but stability of mixture was limited. We aimed to develop and characterize microcapsules incorporating G with a microcapsule-stabilizing bile acid, ursodeoxycholic acid (UDCA). Sodium alginate (SA)-based microcapsules were prepared with either G or G with UDCA and analyzed in terms of morphological, physico-chemical, and electro-chemical characteristics at different pH and temperatures. The microcapsules' effects on viability on muscle cell line (C2C12) and on diabetic rats' blood glucose levels and inflammatory profiles were also examined. Bile acid-based microcapsules maintained their morphology, showed good stability, and compatibility profiles, and the incorporation of UDCA resulted in less G content per microcapsule (p < 0.01) and production of stronger microcapsules that were more resistant to mechanical pressure (p < 0.01). G-UDCA-SA microcapsules enhanced muscle cell viability at higher glucose concentrations compared with control (G-SA and UDCA-SA), and they had strong anti-inflammatory effects on diabetic rats. In addition, the incorporation of UDCA into G microcapsules enhanced the physical characteristics of the microcapsules and optimized G delivery after oral administration.


Assuntos
Ácidos e Sais Biliares/química , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Tipo 1/tratamento farmacológico , Composição de Medicamentos/métodos , Gliclazida/química , Hipoglicemiantes/química , Administração Oral , Animais , Ácidos e Sais Biliares/uso terapêutico , Cápsulas , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Tipo 1/sangue , Estabilidade de Medicamentos , Gliclazida/uso terapêutico , Hipoglicemiantes/uso terapêutico , Masculino , Camundongos , Distribuição Aleatória , Ratos , Ratos Wistar , Resultado do Tratamento
3.
Microb Drug Resist ; 23(3): 384-390, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27754780

RESUMO

Staphylococcus aureus in biofilms is highly resistant to the treatment with antibiotics, to which the planktonic cells are susceptible. This is likely to be due to the biofilm creating a protective barrier that prevents antibiotics from accessing the live pathogens buried in the biofilm. S. aureus biofilms consist of an extracellular matrix comprising, but not limited to, extracellular bacterial DNA (eDNA) and poly-ß-1, 6-N-acetyl-d-glucosamine (PNAG). Our study revealed that despite inferiority of dispersin B (an enzyme that degrades PNAG) to DNase I that cleaves eDNA, in dispersing the biofilm of S. aureus, both enzymes were equally efficient in enhancing the antibacterial efficiency of tobramycin, a relatively narrow-spectrum antibiotic against infections caused by gram-positive and gram-negative pathogens, including S. aureus, used in this investigation. However, a combination of these two biofilm-degrading enzymes was found to be significantly less effective in enhancing the antimicrobial efficacy of tobramycin than the individual application of the enzymes. These findings indicate that combinations of different biofilm-degrading enzymes may compromise the antimicrobial efficacy of antibiotics and need to be carefully assessed in vitro before being used for treating medical devices or in pharmaceutical formulations for use in the treatment of chronic ear or respiratory infections.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Biofilmes/efeitos dos fármacos , Desoxirribonuclease I/metabolismo , Staphylococcus aureus/efeitos dos fármacos , Tobramicina/farmacologia , DNA Bacteriano/genética , Testes de Sensibilidade Microbiana/métodos , Staphylococcus aureus/metabolismo
4.
Artif Cells Nanomed Biotechnol ; 44(5): 1290-7, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25811999

RESUMO

We have demonstrated a permeation-enhancing effect of deoxycholic acid (DCA), the bile acid, in diabetic rats. In this study, we designed DCA-based microcapsules for the oral delivery of the antilipidemic drug probucol (PB), which has potential antidiabetic effects. We aimed to further characterize these microcapsules and examine their pH-dependent release properties, as well as the effects of DCA on their stability and mechanical strength at various pH and temperature values. Using the polymer sodium alginate (SA), we prepared PB-SA (control) and PB-DCA-SA (test) microcapsules. The microcapsules were examined for drug content, size, surface composition, release, Micro-CT cross-sectional imaging, stability, Zeta potential, mechanical strength, and swelling characteristics at different pH and temperature values. The microencapsulation efficiency and production yield were also examined. The addition of DCA resulted in microcapsules with a greater density and with reduced swelling at a pH of 7.8 and at temperatures of 25°C and 37°C (p < 0.01). The size, surface composition, production yield, and microencapsulation efficiency of the microcapsules remained similar after DCA addition. PB-SA microcapsules produced multiphasic PB release, while PB-DCA-SA microcapsules produced monophasic PB release, suggesting more controlled PB release in the presence of DCA. The PB-DCA-SA microcapsules showed good stability and a pH-sensitive uniphasic release pattern, which may suggest potential applications in the oral delivery of PB in diabetes.


Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Hipoglicemiantes , Probucol , Administração Oral , Animais , Cápsulas , Hipoglicemiantes/química , Hipoglicemiantes/farmacocinética , Hipoglicemiantes/farmacologia , Probucol/química , Probucol/farmacocinética , Probucol/farmacologia , Ratos
5.
Artif Cells Nanomed Biotechnol ; 44(2): 588-95, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-25358121

RESUMO

This study utilized the Seahorse Analyzer to examine the effect of the bile acid ursodeoxycholic acid (UDCA), on the morphology, swelling, stability, and size of novel microencapsulated ß-cells, in real-time. UDCA was conjugated with fluorescent compounds, and its partitioning within the microcapsules was examined using confocal microscopy. UDCA produced microcapsules with good morphology, better mechanical strength (p < 0.01), and reduced swelling properties (p < 0.01), but lower cell viability (p < 0.05) and cell count per microcapsule (p < 0.01). UDCA reduced the cells' biochemical activities, mitochondrial respiration, and energy production, post-microencapsulation. This is the first time biological functions of microencapsulated ß-cells have been analyzed in real-time.


Assuntos
Diabetes Mellitus/tratamento farmacológico , Diabetes Mellitus/patologia , Células Secretoras de Insulina/efeitos dos fármacos , Ácido Ursodesoxicólico/química , Ácido Ursodesoxicólico/farmacologia , Cápsulas , Linhagem Celular , Respiração Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Química Farmacêutica , Estabilidade de Medicamentos , Corantes Fluorescentes/química , Células Secretoras de Insulina/patologia , Fenômenos Mecânicos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Ácido Ursodesoxicólico/uso terapêutico
6.
Artif Cells Nanomed Biotechnol ; 44(6): 1508-19, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26212118

RESUMO

Gliclazide (G) is used to treat type 2 diabetes (T2D), and also has anti-platelet, anti-radical, and anti-inflammatory effects. G has poor water solubility and high inter-individual variations in absorption, limiting its application in type 1 diabetes (T1D). The bile acid, chenodeoxycholic acid (CDCA), has permeation-enhancing effects. Sodium alginate (SA) was used to microencapsulate G and CDCA to produce control (G-SA) and test (G-CDCA-SA) microcapsules. Both microcapsules showed uniform structure, morphology, and good stability profiles. CDCA reduced G-release at pH 7.8, while G-release was negligible at lower pH values in both microcapsules. CDCA incorporation resulted in less swelling and stronger microcapsules, suggesting improved stability.


Assuntos
Ácido Quenodesoxicólico , Diabetes Mellitus Tipo 1/tratamento farmacológico , Gliclazida , Hipoglicemiantes , Administração Oral , Alginatos/química , Alginatos/farmacocinética , Alginatos/farmacologia , Cápsulas , Ácido Quenodesoxicólico/química , Ácido Quenodesoxicólico/farmacocinética , Ácido Quenodesoxicólico/farmacologia , Composição de Medicamentos , Gliclazida/química , Gliclazida/farmacocinética , Gliclazida/farmacologia , Ácido Glucurônico/química , Ácido Glucurônico/farmacocinética , Ácido Glucurônico/farmacologia , Ácidos Hexurônicos/química , Ácidos Hexurônicos/farmacocinética , Ácidos Hexurônicos/farmacologia , Humanos , Hipoglicemiantes/química , Hipoglicemiantes/farmacocinética , Hipoglicemiantes/farmacologia
7.
Drug Deliv ; 23(8): 2869-2880, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26610261

RESUMO

CONTEXT: Gliclazide (G) is a commonly prescribed drug for Type 2 diabetes (T2D). In a recent study, we found that when G was combined with a primary bile acid, and gavaged to an animal model of Type 1 diabetes (T1D), it exerted a hypoglycemic effect. We hypothesized this to be due to metabolic activation of the primary bile acid into a secondary or a tertiary bile acid, which enhanced G solubility and absorption. The tertiary bile acid, taurocholic acid (TCA), has shown strong permeation-enhancing effects in vivo. Thus, we aimed to design, characterize, and test microcapsules incorporating G and TCA in an animal model of T1D. METHODS: Microcapsules were prepared using the polymer sodium alginate (SA). G-SA microcapsules (control) and G-TCA-SA microcapsules (test) were extensively examined (in-vitro) at different pH and temperatures. The microcapsules were gavaged to diabetic rats, and blood glucose and G concentrations in serum were examined. Ex-vivo studies were also performed using a muscle cell line (C2C12), and cell viability and glucose intake post-treatment were examined. RESULTS: G-TCA-SA microcapsules showed good stability, uniformity, and thermal and chemical excipient compatibilities. TCA did not change the size or the shape of the microcapsules, but it enhanced their mechanical resistance and reduced their swelling properties. G-TCA-SA enhanced the viability of C2C12 cells over 24 hours, and exerted a hypoglycemic effect in alloxan-induced type-1 diabetic rats. CONCLUSIONS: The incorporation of TCA into G-microcapsules resulted in functionally improved microcapsules with a positive effect on cell viability and glycemic control in Type-1 diabetic animals.


Assuntos
Ácidos e Sais Biliares/química , Cápsulas/farmacologia , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Tipo 1/tratamento farmacológico , Gliclazida/farmacologia , Hipoglicemiantes/farmacologia , Alginatos/química , Animais , Glicemia/efeitos dos fármacos , Cápsulas/química , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de Doenças , Composição de Medicamentos/métodos , Excipientes/química , Gliclazida/química , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Hipoglicemiantes/química , Tamanho da Partícula , Solubilidade , Ácido Taurocólico/química
8.
Pharm Dev Technol ; 20(6): 702-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-24798888

RESUMO

INTRODUCTION: In previous studies, we have shown that a gliclazide-cholic acid derivative (G-CA) mixture resulted in an enhanced ileal permeation of G (ex vivo). When administered orally to diabetic rats, it brought about a significant hypoglycaemic effect. In this study, we aim to create a novel microencapsulated-formulation of G-CA with uniform and coherent structure that can be further tested in our rat model of type 1 diabetes (T1D). We also aim to examine the effect of CA addition to G microcapsules in the morphology, structure and excipients' compatibility of the newly designed microcapsules. METHOD: Microencapsulation was carried out using our Buchi-based microencapsulating system developed in our laboratory. Using sodium alginate (SA) polymer, both formulations were prepared: G-SA (control) and G-CA-SA (test) at a constant ratio (1:3:30), respectively. Complete characterizations of microcapsules were carried out. RESULTS: The new G-CA-SA formulation is further optimized by the addition of CA exhibiting pseudoplastic-thixotropic rheological characteristics. Bead size remains similar after CA addition, the new microcapsules show no chemical interactions between the excipients and this was supported further by the spectral studies suggesting bead stability. CONCLUSION: The new microencapsulated-formulation has good and uniform structural properties and may be suitable for oral delivery of antidiabetic-bile acid formulations.


Assuntos
Alginatos/química , Ácido Cólico/química , Portadores de Fármacos/química , Gliclazida/administração & dosagem , Hipoglicemiantes/administração & dosagem , Administração Oral , Animais , Cápsulas , Diabetes Mellitus Tipo 1/tratamento farmacológico , Composição de Medicamentos/métodos , Excipientes/química , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Ratos
9.
Drug Des Devel Ther ; 8: 1673-83, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25302020

RESUMO

The authors have previously designed, developed, and characterized a novel microencapsulated formulation as a platform for the targeted delivery of therapeutics in an animal model of type 2 diabetes, using the drug probucol (PB). The aim of this study was to optimize PB microcapsules by incorporating the bile acid deoxycholic acid (DCA), which has good permeation-enhancing properties, and to examine its effect on microcapsules' morphology, rheology, structural and surface characteristics, and excipients' chemical and thermal compatibilities. Microencapsulation was carried out using a BÜCHI-based microencapsulating system established in the authors' laboratory. Using the polymer sodium alginate (SA), two microencapsulated formulations were prepared: PB-SA (control) and PB-DCA-SA (test) at a constant ratio (1:30 and 1:3:30, respectively). Complete characterization of the microcapsules was carried out. The incorporation of DCA resulted in better structural and surface characteristics, uniform morphology, and stable chemical and thermal profiles, while size and rheological parameters remained similar to control. In addition, PB-DCA-SA microcapsules showed good excipients' compatibilities, which were supported by data from differential scanning calorimetry, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersive X-ray studies, suggesting microcapsule stability. Hence, PB-DCA-SA microcapsules have good rheological and compatibility characteristics and may be suitable for the oral delivery of PB in type 2 diabetes.


Assuntos
Ácidos e Sais Biliares/química , Probucol/administração & dosagem , Probucol/química , Varredura Diferencial de Calorimetria , Química Farmacêutica , Composição de Medicamentos , Probucol/síntese química , Probucol/farmacocinética , Espectroscopia de Infravermelho com Transformada de Fourier , Viscosidade
10.
Drug Des Devel Ther ; 8: 1221-30, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25246766

RESUMO

INTRODUCTION: In previous studies, we successfully designed complex multicompartmental microcapsules as a platform for the oral targeted delivery of lipophilic drugs in type 2 diabetes (T2D). Probucol (PB) is an antihyperlipidemic and antioxidant drug with the potential to show benefits in T2D. We aimed to create a novel microencapsulated formulation of PB and to examine the shape, size, and chemical, thermal, and rheological properties of these microcapsules in vitro. METHOD: Microencapsulation was carried out using the Büchi-based microencapsulating system developed in our laboratory. Using the polymer, sodium alginate (SA), empty (control, SA) and loaded (test, PB-SA) microcapsules were prepared at a constant ratio (1:30). Complete characterizations of microcapsules, in terms of morphology, thermal profiles, dispersity, and spectral studies, were carried out in triplicate. RESULTS: PB-SA microcapsules displayed uniform and homogeneous characteristics with an average diameter of 1 mm. The microcapsules exhibited pseudoplastic-thixotropic characteristics and showed no chemical interactions between the ingredients. These data were further supported by differential scanning calorimetric analysis and Fourier transform infrared spectral studies, suggesting microcapsule stability. CONCLUSION: The new PB-SA microcapsules have good structural properties and may be suitable for the oral delivery of PB in T2D. Further studies are required to examine the clinical efficacy and safety of PB in T2D.


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Sistemas de Liberação de Medicamentos , Hipoglicemiantes/uso terapêutico , Probucol/uso terapêutico , Administração Oral , Alginatos/administração & dosagem , Alginatos/química , Composição de Medicamentos , Ácido Glucurônico/administração & dosagem , Ácido Glucurônico/química , Ácidos Hexurônicos/administração & dosagem , Ácidos Hexurônicos/química , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/química , Tamanho da Partícula , Probucol/administração & dosagem , Probucol/química , Propriedades de Superfície
11.
Drug Des Devel Ther ; 8: 1003-12, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25114507

RESUMO

Gliclazide (G) is an antidiabetic drug commonly used in type 2 diabetes. It has extrapancreatic hypoglycemic effects, which makes it a good candidate in type 1 diabetes (T1D). In previous studies, we have shown that a gliclazide-bile acid mixture exerted a hypoglycemic effect in a rat model of T1D. We have also shown that a gliclazide-deoxycholic acid (G-DCA) mixture resulted in better G permeation in vivo, but did not produce a hypoglycemic effect. In this study, we aimed to develop a novel microencapsulated formulation of G-DCA with uniform structure, which has the potential to enhance G pharmacokinetic and pharmacodynamic effects in our rat model of T1D. We also aimed to examine the effect that DCA will have when formulated with our new G microcapsules, in terms of morphology, structure, and excipients' compatibility. Microencapsulation was carried out using the Büchi-based microencapsulating system developed in our laboratory. Using sodium alginate (SA) polymer, both formulations were prepared: G-SA (control) at a ratio of 1:30, and G-DCA-SA (test) at a ratio of 1:3:30. Complete characterization of microcapsules was carried out. The new G-DCA-SA formulation was further optimized by the addition of DCA, exhibiting pseudoplastic-thixotropic rheological characteristics. The size of microcapsules remained similar after DCA addition, and these microcapsules showed no chemical interactions between the excipients. This was supported further by the spectral and microscopy studies, suggesting microcapsule stability. The new microencapsulated formulation has good structural properties and may be useful for the oral delivery of G in T1D.


Assuntos
Células Artificiais/química , Ácido Desoxicólico/química , Diabetes Mellitus Experimental/tratamento farmacológico , Gliclazida/administração & dosagem , Alginatos/química , Animais , Cápsulas , Química Farmacêutica , Diabetes Mellitus Tipo 1/tratamento farmacológico , Excipientes/química , Gliclazida/química , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/química , Tamanho da Partícula , Ratos , Reologia
12.
J Pharm Innov ; 9: 150-157, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24829616

RESUMO

INTRODUCTION: In previous studies carried out in our laboratory, a bile acid (BA) formulation exerted a hypoglycaemic effect in a rat model of type-1 diabetes (T1D). When the antidiabetic drug gliclazide (G) was added to the bile acid, it augmented the hypoglycaemic effect. In a recent study, we designed a new formulation of gliclazide-cholic acid (G-CA), with good structural properties, excipient compatibility and exhibits pseudoplastic-thixotropic characteristics. The aim of this study is to test the slow release and pH-controlled properties of this new formulation. The aim is also to examine the effect of CA on G release kinetics at various pH values and different temperatures. METHOD: Microencapsulation was carried out using our Buchi-based microencapsulating system developed in our laboratory. Using sodium alginate (SA) polymer, both formulations were prepared: G-SA (control) and G-CA-SA (test) at a constant ratio (1:3:30), respectively. Microcapsules were examined for efficiency, size, release kinetics, stability and swelling studies at pH 1.5, pH 3, pH 7.4 and pH 7.8 and temperatures of 20 and 30 °C. RESULTS: The new formulation is further optimised by the addition of CA. CA reduced microcapsule swelling of the microcapsules at pH 7.8 and pH 3 at 30 °C and pH 3 at 20 °C, and, even though microcapsule size remains similar after CA addition, percent G release was enhanced at high pH values (pH 7.4 and pH 7.8, p < 0.01). CONCLUSION: The new formulation exhibits colon-targeted delivery and the addition of CA prolonged G release suggesting its suitability for the sustained and targeted delivery of G and CA to the lower intestine.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA