921 resultados para in vitro drug release


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Parkinson´s disease (PD) is a debilitating age-related neurological disorder that affects various motor skills and can lead to a loss of cognitive functions. The motor symptoms are the result of the progressive degeneration of dopaminergic neurons within the substantia nigra. The factors that influence the pathogenesis and the progression of the neurodegeneration remain mostly unclear. This study investigated the role of various programmed cell death (PCD) pathways, oxidative stress, and glial cells both in dopaminergic neurodegeneration and in the protective action of various drugs. To this end, we exposed dopaminergic neuroblastoma cells (SH-SY5Y cells) to 6-OHDA, which produces oxidative stress and activates various PCD modalities that result in neuronal degeneration. Additionally, to explore the role of glia, we prepared rat midbrain primary mixed-cell cultures containing both neurons and glial cell types such as microglia and astroglia and then exposed the cultures to either MPP plus or lipopolysaccharide. Our results revealed that 6-OHDA activated several PCD pathways including apoptosis, autophagic stress, lysosomal membrane permeabilization, and perhaps paraptosis in SH-SY5Y cells. Furthermore, we found that minocycline protected SH-SY5Y cells from 6-OHDA by inhibiting both apoptotic and non-apoptotic PCD modalities. We also observed an inconsistent neuroprotective effect of various dietary anti-oxidant compounds against 6-OHDA toxicity in vitro in SH-SY5Y cells. Specifically, quercetin and curcumin exerted neuroprotection only within a narrow concentration range and a limited time frame, whereas resveratrol and epigallocatechin 3-gallate provided no protection whatsoever. Lastly, we found that molecules such as amantadine may delay or even halt the neurodegeneration in primary cell cultures by inhibiting the release of neurotoxic factors from overactivated microglia and by enhancing the pro-survival actions of astroglia. Together these data suggest that the strategy of dampening oxidative species with anti-oxidants is less effective than preventing the production of toxic factors such as oxidative and pro-inflammatory molecules by pathologically activated microglia. This would subsequently prevent the activation of various PCD modalities that cause neuronal degeneration.

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Several H-2 defined cell lines were examined for their ability to support infection and replication of Japanese encephalitis virus (JEV) before their use in in vitro and in vivo stimulation protocols for generating cytotoxic T lymphocytes (CTLs) against JEV. Among II different cell lines tested, two H-2(d) macrophage tumour lines (P388D1, RAW 264.7), an H-2(d) hybridoma (Sp2/0), an H-2K(k)D(d) neuroblastoma (Neuro 2a), and H-2(k) fibroblast cell line (L929) were found to support JEV infection and replication. These cell lines were used to generate anti-JEV CTLs by using in vivo immunization followed by in vitro stimulation of BALB/c mice. We observed that not only syngeneic and allogeneic infected cells but also JEV-infected xenogeneic cells could prime BALB/c mice for the generation of JEV-specific CTLs upon subsequent in vitro stimulation of splenocytes with JEV-infected syngeneic cells. Although infected xenogeneic cells were used for immunization, the anti-JEV effecters that were generated lysed infected syngeneic targets but not JEV-infected xenogeneic or allogeneic target cells in a 5h Cr-51 release assay. These anti-JEV effecters recognized syngeneic target cells infected with West Nile virus to a lesser extent and were shown to be Lyt-2.2(+) T cells. The results of unlabelled cold target competition studies suggested alterations in the cell surface expression of viral antigenic determinants recognized by these CTLs. We further demonstrate that the JEV-specific CTLs generated could virtually block the release of infectious virus particles from infected P388D1 and Neuro 2a cells in vitro.

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Owing to the reduced co-relationship between conventional flat Petri dish culture (two-dimensional) and the tumour microenvironment, there has been a shift towards three-dimensional culture systems that show an improved analogy to the same. In this work, an extracellular matrix (ECM)-mimicking three-dimensional scaffold based on chitosan and gelatin was fabricated and explored for its potential as a tumour model for lung cancer. It was demonstrated that the chitosan-gelatin (CG) scaffolds supported the formation of tumoroids that were similar to tumours grown in vivo for factors involved in tumour-cell-ECM interaction, invasion and metastasis, and response to anti-cancer drugs. On the other hand, the two-dimensional Petri dish surfaces did not demonstrate gene-expression profiles similar to tumours grown in vivo. Further, the three-dimensional CG scaffolds supported the formation of tumoroids, using other types of cancer cells such as breast, cervix and bone, indicating a possible wider potential for in vitro tumoroid generation. Overall, the results demonstrated that CG scaffolds can be an improved in vitro tool to study cancer progression and drug screening for solid tumours.

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Objectives: Modified starches based polymeric substances find utmost applicability in pharmaceutical formulation development. Cross-linked starches showed very promising results in drug delivery application. The present investigation concerns with the development of controlled release tablets of lamivudine using cross-linked sago starch. Methods: The cross-linked derivative was synthesized with phosphorous oxychloride and native sago starch in basic pH medium. The cross-linked sago starch was tested for acute toxicity and drug-excipient compatibility study. The formulated tablets were evaluated for various physical characteristics, in vitro dissolution release study and in vivo pharmacokinetic study in rabbit model. Results: In vitro release study showed that the optimized formulation exhibited highest correlation (R) in case of zero order kinetic model and the release mechanism followed a combination of diffusion and erosion process. There was a significant difference in the pharmacokinetic parameters (T-max, C-max, AUC, V-d, T-1/2, and MDT) of the optimized formulation as compared to the marketed conventional tablet Lamivir (R). Conclusion: The cross-linked starch showed promising results in terms of controlling the release behavior of the active drug from the matrix. The hydrophilic matrix synthesized by cross-linking could be used with a variety of active pharmaceutical ingredients for making their controlled/sustained release formulations.

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Neutral and cationic copper bis(thiosemicarbazone) complexes bearing methyl, phenyl, and hydrogen, on the diketo-backbone of the ligand have been synthesized. All of them were characterized by spectroscopic methods and in three cases by X-ray crystallography. In vitro cytotoxicity studies revealed that they are cytotoxic unlike the corresponding zinc complexes. Copper complexes Cu(GTSC) and Cu(GTSCHCl) derived from glyoxal-bis(4-methyl-4-phenyl-3-thiosemicarbazone) (GTSCH(2)) are the most cytotoxic complexes against various human cancer cell lines, with a potency similar to that of the anticancer drug adriamycin and up to 1000 fold higher than that of the corresponding zinc complex. Tritiated thymidine incorporation assay revealed that Cu(GTSC) and Cu(GTSCHCl) inhibit DNA synthesis substantially. Cell cycle analyses showed that Cu(GTSC) and Cu(GTSCHCl) induce apoptosis in HCT116 cells. The Cu(GTSCHCl) complex caused distinct DNA cleavage and Topo II alpha inhibition unlike that for Cu(GTSC). In vivo administration of Cu(GTSC) significantly inhibits tumor growth in HCT116 xenografts in nude mice.

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Four dinucleating bis(thiosemicarbazone) ligands and their zinc complexes have been synthesized and characterized by multinuclear NMR (H-1 and C-13), IR, UV-Vis, ESI-MS and fluorescence spectroscopic techniques. Their purity was assessed by elemental analysis. Cytotoxicity was tested against five human cancer cell lines using the sulphorhodamine B (SRB) assay, where one of the complexes, 1,3-bis{biacetyl-2'-(4 `'-N-pyrrolidinylthiosemicarbazone)-3'-(4 `'-N-pyrrolidinylthiosemicarbazone) zinc(II)} propane (6), was found to be quite cytotoxic against MCF-7 (breast cancer) and HepG2 (hepatoma cancer) cell lines, with a potency similar to that of the well known anticancer drug adriamycin. It is evident from the cellular uptake studies that the uptake is same for the active complex 6 and the inactive complex 8 (1,6-bis{biacetyl- 2'-(4 `'-N-pyrrolidinylthiosemicarbazone)-3'-(4 `'-N-pyrrolidinylthiosemicarbazone) zinc(II)} hexane) in MCF-7 and HepG2 cell lines. In vitro DNA binding and cleavage studies revealed that all complexes bind with DNA through electrostatic interaction, and cause no significant cleavage of DNA. (C) 2'13 Elsevier B. V. All rights reserved.

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Mesoporous quaternary bioactive glasses and glass-ceramic with alkali-alkaline-earth oxide were successfully synthesized by using non-ionic block copolymer P123 and evaporation induced self assembly (EISA) process followed by acid treatment assisted sal-gel method. As prepared samples has been characterized for the structural, morphological and textural properties with the various analytical techniques. Glass dissolution/ion release rate in simulated body fluid (SBF) was monitored by inductively coupled plasma (ICP) emission spectroscopy, whereas the formation of apatite phase and its crystallization at the glass and glass-ceramic surface was examined by structural, textural and microscopic probes. The influence of alkaline-earth oxide content on the glass structure followed by textural property has become more evident. The pristine glass samples exhibit a wormhole-like mesoporous structure, whereas the glass-ceramic composition is found to be in three different phases, namely crystalline hydroxyapatite, wollastonite and a residual glassy phase as observed in Cerabone (R) A/W. The existence of calcium orthophosphate phase is closely associated with the pore walls comprising nanometric-sized ``inclusions''. The observed high surface area in conjunction with the structural features provides the possible explanation for experimentally observed enhanced bioactivity through the easy access of ions to the fluid. On the other hand, presence of multiple phases in glass-ceramic sample inhibits or delays the kinetics of apatite formation. (C) 2013 Elsevier Inc. All rights reserved.

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With the progress in modern technological research, novel biomaterials are being largely developed for various biomedical applications. Over the past two decades, most of the research focuses on the development of a new generation of bioceramics as substitutes for hard tissue replacement. In reference to their application in different anatomical locations of a patient, newly developed bioceramic materials can potentially induce a toxic/harmful effect to the host tissues. Therefore, prior to clinical testing, relevant biochemical screening assays are to be performed at the cellular and molecular level, to address the issues of biocompatibility and long term performance of the implants. Along with testing strategies in the bulk material toxicity, a detailed evaluation should also be conducted to determine the toxicity of the wear products of the potential bioceramics. This is important as the bioceramics are intended to be implanted in patients with longer life expectancy and notwithstanding, the material will eventually release finer (mostly nanosized) sized debris particles due to continuous wear at articulating surfaces in the hostile corrosive environment of the human body. The wear particulates generated from a biocompatible bioceramic may act in a different way, inducing early/late aseptic loosening at the implant site, resulting in osteolysis and inflammation. Hence, a study on the chronic effects of the wear particulates, in terms of local and systemic toxicity becomes the major criteria in the toxicity evaluation of implantable bioceramics. In this broad perspective, this article summarizes some of the currently used techniques and knowledge in assessing the in vitro and in vivo cytotoxicity and genotoxicity of bioceramic implant materials. It also addresses the need to conduct a broad evaluation before claiming the biocompatibility and clinical feasibility of any new biomaterial. This review also emphasizes some of the case studies based on the experimental designs that are currently followed and its importance in the context of clinical applications.

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In order to suppress chronic inflammation while supporting cell proliferation, there has been a continuous surge toward development of polymers with the intention of delivering anti-inflammatory molecules in a sustained manner. In the above backdrop, we report the synthesis of a novel, stable, cross-linked polyester with salicylic acid (SA) incorporated in the polymeric backbone and propose a simple synthesis route by melt condensation. The as-synthesized polymer was hydrophobic with a glass transition temperature of 1 degrees C, which increases to 17 degrees C upon curing. The combination of NMR and FT-IR spectral techniques established the ester linkages in the as-synthesized SA-based polyester. The pH-dependent degradation rate and the rate of release of salicylic acid from the as-synthesized SA-based polymer were studied at physiological conditions in vitro. The polyester underwent surface erosion and exhibited linear degradation kinetics in which a change in degradation rate is observed after 4-10 days and 24% mass loss was recorded after 4 months at 37 degrees C and pH 7.4. The delivery of salicylic acid also showed a similar change in slopes, with a sustained release rate of 3.5% in 4 months. The cytocompatibility studies of these polyesters were carried out with C2C12 murine myoblast cells using techniques like MTT assay and flow cytometry. Our results strongly suggest that SA-based polyester supports cell proliferation for 3 days in culture and do not cause cell death (<7%), as quantified by propidium iodide (PI) stained cells. Hence, these polyesters can be used as implant materials for localized, sustained delivery of salicylic acid and have applications in adjuvant cancer therapy, chronic wound healing, and as an alternative to commercially available polymers like poly(lactic acid) and poly(glycolic acid) or their copolymers.

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The fabrication of a mesoporous silica nanoparticle (MSN)-protamine hybrid system (MSN-PRM) is reported that selectively releases drugs in the presence of specific enzyme triggers present in the proximity of cancer cells. The enzyme trigger involved is a protease called trypsin, which is overexpressed in certain specific pathological conditions, such as inflammation and cancer. Overexpression of trypsin is known to be associated with invasion, metastasis, and growth in several cancers, such as leukemia, colon cancer, and colorectal cancer. The current system (MSN-PRM) consists of an MSN support in which mesopores are capped with an FDA-approved peptide drug protamine, which effectively blocks the outward diffusion of the drug molecules from the mesopores of the MSNs. On exposure to the enzyme trigger, the protamine cap disintegrates, opening up the molecular gates and releasing the entrapped drug molecules. The system exhibits minimal premature release in the absence of the trigger and selectively releases the encapsulated drugs in the presence of the proteases secreted by colorectal cancer cells. The ability of the MSN-PRM particles to deliver anticancer drugs to colorectal cancer cells has also been demonstrated. The hydrophobic drug is released into cancer cells subsequent to disintegration of the protamine cap, resulting in cell death. Drug-induced cell death in colorectal cancer cells is significantly enhanced when the hydrophobic drug that is known to degrade in aqueous environments is encapsulated in the MSN-PRM system in comparison to the free drug (P < 0.05). The system, which shows good biocompatibility and selective drug release, is a promising platform for cancer specific drug delivery.

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We investigated the potential of using novel zoledronic acid (ZOL)-hydroxyapatite (HA) nanoparticle based drug formulation in a rat model of postmenopausal osteoporosis. By a classical adsorption method, nanoparticles of HA loaded with ZOL (HNLZ) drug formulation with a size range of 100-130 nm were prepared. 56 female Wistar rats were ovariectomized (OVX) or sham-operated at 3 months of age. Twelve weeks post surgery, rats were randomized into seven groups and treated with various doses of HNLZ (100, 50 and 25 mu g/kg, intravenous single dose), ZOL (100 mu g/kg, intravenous single dose) and HA nanoparticle (100 mu g/kg, intravenous single dose). Untreated OVX and sham OVX served as controls. After three months treatment period, we evaluated the mechanical properties of the lumbar vertebra and femoral mid-shaft. Femurs were also tested for trabecular microarchitecture. Sensitive biochemical markers of bone formation and bone resorption in serum were also determined. With respect to improvement in the mechanical strength of the lumbar spine and the femoral mid-shaft, the therapy with HNLZ drug formulation was more effective than ZOL therapy in OVX rats. Moreover, HNLZ drug therapy preserved the trabecular microarchitecture better than ZOL therapy in OVX rats. Furthermore, the HNLZ drug formulation corrected increase in serum levels of bone-specific alkaline phosphatase, procollagen type I N-terminal propeptide, osteocalcin, tartrate-resistant acid phosphatase 5b and C-telopeptide of type 1 collagen better than ZOL therapy in OVX rats. The results strongly suggest that HNLZ novel drug formulation appears to be more effective approach for treating severe osteoporosis in humans. (C) 2014 Elsevier B.V. All rights reserved.

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Tissue engineering deals with the regeneration of tissues for bone repair, wound healing, drug delivery, etc., and a highly porous 3D artificial scaffold is required to accommodate the cells and direct their growth. We prepared 3D porous calcium phosphate ((hydroxyapatite/beta-tricalcium phosphate)/agarose, (HAp/beta-TCP)/agarose) composite scaffolds by sol-gel technique with water (WBS) and ethanol (EBS) as solvents. The crystalline phases of HAp and beta-TCP in the scaffolds were confirmed by X-ray diffraction (XRD) analysis. The EBS had reduced crystallinity and crystallite size compared to WBS. WBS and EBS revealed interconnected pores of 1 mu m and 100 nm, respectively. The swelling ratio was higher for EBS in water and phosphate buffered saline (PBS). An in vitro drug loading/release experiment was carried out on the scaffolds using gentamicin sulphate (GS) and amoxicillin (AMX). We observed initial burst release followed by sustained release from WBS and EBS. In addition, GS showed more extended release than AMX from both the scaffolds. GS and AMX loaded scaffolds showed greater efficacy against Pseudomonas than Bacillus species. WBS exhibited enhanced mechanical properties, wettability, drug loading and haemocompatibility compared to EBS. In vitro cell studies showed that over the scaffolds, MC3T3 cells attached and proliferated and there was a significant increase in live MC3T3 cells. Both scaffolds supported MC3T3 proliferation and mineralization in the absence of osteogenic differentiation supplements in media which proves the scaffolds are osteoconducive. Microporous scaffolds (WBS) could assist the bone in-growth, whereas the presence of nanopores (EBS) could enhance the degradation process. Hence, WBS and EBS could be used as scaffolds for tissue engineering and drug delivery. This is a cost effective technique to produce scaffolds of degradable 3D ceramic-polymer composites.

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Andrographis lineata is an herbal medicinal plant used in traditional medicine as a substitute for Andrographis paniculata. Here, using mature leaf explants of A. lineata we demonstrate for the first time the callus induction established on MS medium containing 1.0 mg l(-1) IAA. Dried callus was subjected to solvent extraction with acetone. Further the acetone residue was separated by silica gel column chromatography, crystallized and characterized on the basis of nuclear magnetic resonance (proton and c13) and liquid chromatographic mass spectroscopy. This analysis revealed the occurrence of two known flavones namely, 7-O-methylwogonin (MW) and Echioidinin (ED). Furthermore, these compounds were tested for their cytotoxicity against leukemic cell line, CEM. We identify that ED and MW induced cytotoxicity in a time-and concentration-dependent manner. Further increase in the LDH release upon treatment with ED and MW further confirmed our cytotoxicity results against leukemic cell line. Strikingly, MW was more potent than ED when compared by trypan blue and MTT assays. Our results recapitulate the utility of callus cultures for the production of plant specific bioactive secondary metabolites instead of using wild plants. Together, our in vitro studies provide new insights of A. lineata callus cultures serving as a source for cancer chemotherapeutic agents.

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Hepatic cell culture on a three-dimensional (3D) matrix or as a hepatosphere appears to be a promising in vitro biomimetic system for liver tissue engineering applications. In this study, we have combined the concept of a 3D scaffold and a spheroid culture to develop an in vitro model to engineer liver tissue for drug screening. We have evaluated the potential of poly(ethylene glycol)-alginate-gelatin (PAG) cryogel matrix for in vitro culture of human liver cell lines. The synthesized cryogel matrix has a flow rate of 7 mL/min and water uptake capacity of 94% that enables easy nutrient transportation in the in vitro cell culture. Youngs modulus of 2.4 kPa and viscoelastic property determine the soft and elastic nature of synthesized cryogel. Biocompatibility of PAG cryogel was evaluated through MTT assay of HepG2 and Huh-7 cells on matrices. The proliferation and functionality of the liver cells were enhanced by culturing hepatic cells as spheroids (hepatospheres) on the PAG cryogel using temperature-reversible soluble-insoluble polymer, poly(N-isopropylacrylamide) (PNIPAAm). Pore size of the cryogel above 100 mu m modulated spheroid size that can prevent hypoxia condition within the spheroid culture. Both the hepatic cells have shown a significant difference (P < 0.05) in terms of cell number and functionality when cultured with PNIPAAm. After 10 days of culture using 0.05% PNIPAAm, the cell number increased by 11- and 7-fold in case of HepG2 and Huh-7 cells, respectively. Similarly, after 10 days of hepatic spheroids culture on PAG cryogel, the albumin production, urea secretion, and CYP450 activity were significantly higher in case of culture with PNIPAAm. The developed tissue mass on the PAG cryogel in the presence of PNIPAAm possess polarity, which was confirmed using F-actin staining and by presence of intercellular bile canalicular lumen. The developed cryogel matrix supports liver cells proliferation and functionality and therefore can be used for in vitro and in vivo drug testing.

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As leishmanioses estão entre as mais importantes endemias brasileiras e encontram-se entre as doenças mais negligenciadas no mundo. O arsenal terapêutico disponível é restrito, tóxico, caro e em algumas situações ineficazes, devido ao surgimento de cepas resistentes do parasito. No Brasil são registrados anualmente mais de 20 mil casos de leishmaniose tegumentar e a Leishmania braziliensis é a principal espécie causadora das formas clínicas cutânea e mucosa. Portanto tornam-se importantes estudos que conduzam ao desenvolvimento de novas alternativas terapêuticas. O objetivo do presente estudo foi avaliar a atividade da pterocarpanoquinona denominada LQB118 sobre Leishmania braziliensis in vitro e in vivo usando hamsters como modelo experimental. O efeito antiparasitário foi avaliado sobre o crescimento in vitro das formas promastigotas e sobre amastigotas intracelulares em macrófagos peritoneais de camundongos. Para avaliar o modo ação in vitro foi investigada a indução de apoptose usando marcação por TUNEL e Anexina V-FITC. O efeito sobre a modulação da ativação de macrófagos murinos foi analisada pela dosagem de óxido nítrico (reagente de Griess) e de citocinas IL-12, TNF-alfa e IL-10 (por ELISA) nos sobrenadantes de macrófagos. In vivo a atividade terapêutica da LQB 118 foi estudada em grupos de hamsters infectados com L.braziliensis na pata, tratados com a LQB118 pelas vias intralesional (100M/3x/semana) ou oral (0,5mg/5x/semana) após 7 dias de infecção durante oito semanas. A ação terapêutica foi analisada através do tamanho da lesão. A resposta imune foi avaliada durante o tratamento, pela resposta de hipersensibilidade tardia (DTH) ao antígeno total de L. braziliensis. A ação da LQB118 in vitro foi dose-dependente tanto na forma promastigota inibindo 45%, 64,7% e 99,95%, quanto nas amastigotas intracelulares 22%, 72% e 81% nas concentrações de 5M, 10M e 20M, respectivamente para ambas as formas evolutivas. A LQB118 foi capaz de induzir a externalização de fosfatidilserina em promastigotas (18,57% das células incubadas por 24 h e em 25,79% de células tratadas por 48h) e também promoveu aumento da fluorescência nas duas formas evolutivas da Leishmania quando comparadas aos controles, demonstrando a indução de fragmentação do DNA do parasito. Esta substância também foi capaz de modular a resposta dos macrófagos infectados por 24 horas aumentando de forma dose-dependente a IL-12 e NO, mantendo constante TNF-α. In vivo, na sétima semana de tratamento, observamos uma redução significativa do tamanho das lesões nos animais tratados com LQB 118 intralesional (p<0, 001) e no grupo tratado pela via oral (p<0,05) quando comparado com o controle. Estes resultados demonstram que a atividade anti-Leishmania da LQB118 é direta sobre o parasito pela indução de morte por apoptose, apresentando também uma ação moduladora da resposta dos macrófagos contribuindo para ação leishmanicida, sem alterar a morfologia da célula hospedeira e que a LQB 118 apresenta uma atividade terapêutica no modelo hamster e pode ser uma importante molécula para o desenvolvimento de um novo fármaco.