389 research outputs found

    Development and in-vitro Evaluation of a Topical Drug Delivery System Containing Betamethazone Loaded Ethyl Cellulose Nanospheres

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    Purpose: Lipid nanospheres are used for the passive targeting of cosmetic agents to skin, thereby achieving major benefits such as reduction of total dose and avoidance of systemic absorption. The present study was carried out to exploit the feasibility of using polymeric nanospheres as an alternative and cheaper carrier for targeting corticosteroids to the skin. Methods: Nanospheres were prepared from ethyl cellulose by a modified method of desolvation and cross linking. The drug betamethazone was incorporated into nanospheres and the drug: polymer ratio was evaluated to determine the carrier capacity of the polymer. In-vitro release studies of drug-loaded nanospheres were carried out by the centrifugal ultrafiltration method. The kinetics of release was determined and fitted to an empirical equation. The release of drug from drug-loaded nanospheres dispersing in a conventional cream was evaluated. A comparative in-vitro diffusion study was carried out between a commercial brand of cream and the cream incorporating nanospheres. Results: Formulation of nanospheres of betamethazone by a modified method produced discrete particles. Studies on drug:polymer ratio showed a linear relationship between drug concentration and percentage of loading. The in-vitro release of drug-loaded nanospheres was found to be first order. The comparative in-vitro diffusion study between the commercial cream and the formulated cream showed a marked reduction in release rate from nanospheres-bound cream. Conclusion: Formulated topical cream containing nanospheres of betamethazone was found to be a potential dermal delivery system for sustaining the release of the drug. Keywords: Nanospheres, desolvation and cross-linking method, ethyl cellulose, betamethazone, in-vitro diffusion studies.> Tropical Journal of Pharmaceutical Research Vol. 4 (2) 2005: pp. 495-50

    Formulation of Sodium Alginate Nanospheres Containing Amphotericin B for the Treatment of Systemic Candidiasis

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    Purpose: The aim of this work was to formulate sodium alginate nanospheres of amphotericin B by controlled gellification method and to evaluate the role of the nanospheres as a “passive carrier” in targeted antifungal therapy. Methods: Sodium alginate nanospheres of amphotericin B were prepared by controlled gellification method, and the particle size analysis was carried out by scanning electron microscopy. The carrier capacity of sodium alginate was evaluated in terms of drug to polymer ratio. In vitro release study was carried out on all drug loaded nanospheres by the dialysis method. Release kinetics of drug from different drug loaded nanospheres was also determined. The in vivo antifungal efficacy of nanospheres bound drug vis-à-vis the free drug was evaluated in candidiasis- induced mice models. Results: Preparation of nanospheres through controlled gellification method yielded particles with a size range of 419.6 ± 0.28 nm. Studies on drug to polymer ratio showed a linear relationship between concentration of drug and drug loading capacity. In vitro release kinetic study revealed that the release of drug from the nanospheres followed Fickian diffusion. In vivo studies showed that the nanosphere-bound drug produced a higher antifungal efficacy than the free drug. Conclusion: The formulated sodium alginate nanospheres containing amphotericin B was found to have better antifungal activity when compared to the free drug and also yielded sustained in vitro release. Keywords: Nanospheres, sodium alginate, amphotericin B, controlled gellification method, in vitro & in vivo release > Tropical Journal of Pharmaceutical Research Vol. 6 (1) 2007: pp. 653-65

    Pressure-induced collapsed-tetragonal phase in SrCo2As2

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    We present high-energy x-ray diffraction data under applied pressures up to p = 29 GPa, neutron diffraction measurements up to p = 1.1 GPa, and electrical resistance measurements up to p = 5.9 GPa, on SrCo2As2. Our x-ray diffraction data demonstrate that there is a first-order transition between the tetragonal (T) and collapsed-tetragonal (cT) phases, with an onset above approximately 6 GPa at T = 7 K. The pressure for the onset of the cT phase and the range of coexistence between the T and cT phases appears to be nearly temperature independent. The compressibility along the a-axis is the same for the T and cT phases whereas, along the c-axis, the cT phase is significantly stiffer, which may be due to the formation of an As-As bond in the cT phase. Our resistivity measurements found no evidence of superconductivity in SrCo2As2 for p <= 5.9 GPa and T >= 1.8 K. The resistivity data also show signatures consistent with a pressure-induced phase transition for p >= 5.5 GPa. Single-crystal neutron diffraction measurements performed up to 1.1 GPa in the T phase found no evidence of stripe-type or A-type antiferromagnetic ordering down to 10 K. Spin-polarized total-energy calculations demonstrate that the cT phase is the stable phase at high pressure with a c/a ratio of 2.54. Furthermore, these calculations indicate that the cT phase of SrCo2As2 should manifest either A-type antiferromagnetic or ferromagnetic order.Comment: 6 pages, 5 figure

    Using qualitative research methods to understand how surgical procedures and devices are introduced into NHS hospitals:The Lotus study protocol

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    INTRODUCTION: The development of innovative invasive procedures and devices are essential to improving outcomes in healthcare. However, how these are introduced into practice has not been studied in detail. The Lotus study will follow a wide range of ‘case studies’ of new procedures and/or devices being introduced into NHS trusts to explore what information is communicated to patients, how procedures are modified over time and how outcomes are selected and reported. METHODS AND ANALYSIS: This qualitative study will use ethnographic approaches to investigate how new invasive procedures and/or devices are introduced. Consultations in which the innovation is discussed will be audio-recorded to understand information provision practice. To understand if and how procedures evolve, they will be video recorded and non-participant observations will be conducted. Post-operative interviews will be conducted with the innovating team and patients who are eligible for the intervention. Audio-recordings will be audio-recorded, transcribed verbatim and analysed thematically using constant comparison techniques. Video-recordings will be reviewed to deconstruct procedures into key components and document how the procedure evolves. Comparisons will be made between the different data sources. ETHICS AND DISSEMINATION: The study protocol has Health Research Authority (HRA) and Health and Care Research Wales approval (Ref 18/SW/0277). Results will be disseminated at appropriate conferences and will be published in peer-reviewed journals. The findings of this study will provide a better understanding of how innovative invasive procedures and/or devices are introduced into practice

    Solvent contribution to the stability of a physical gel characterized by quasi-elastic neutron scattering

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    The dynamics of a physical gel, namely the Low Molecular Mass Organic Gelator {\textit Methyl-4,6-O-benzylidene-α\alpha -D-mannopyranoside (α\alpha-manno)} in water and toluene are probed by neutron scattering. Using high gelator concentrations, we were able to determine, on a timescale from a few ps to 1 ns, the number of solvent molecules that are immobilised by the rigid network formed by the gelators. We found that only few toluene molecules per gelator participate to the network which is formed by hydrogen bonding between the gelators' sugar moieties. In water, however, the interactions leading to the gel formations are weaker, involving dipolar, hydrophobic or ππ\pi-\pi interactions and hydrogen bonds are formed between the gelators and the surrounding water. Therefore, around 10 to 14 water molecules per gelator are immobilised by the presence of the network. This study shows that neutron scattering can give valuable information about the behaviour of solvent confined in a molecular gel.Comment: Langmuir (2015

    Production of fructooligosaccharides and b-fructofuranosidase by batch and repeated batch fermentation with immobilized cells of Penicillium expansum

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    The production of fructooligosaccharides (FOS) and b-fructofuranosidase (FFase) by immobilized cells of Penicillium expansum was evaluated. In an initial stage, different low-cost materials including synthetic fiber, polyurethane foam, stainless steel sponge, loofah sponge, and cork oak were tested as carrier for the fungus immobilization. Additionally, the influence of the inoculum age (1 or 3 weeks) on cells immobilization, FOS and FFase production was also verified. Synthetic fiber and polyurethane foam were the best materials for P. expansum immobilization (2.21 and 1.98 g/g carrier, respectively) and FOS production (120.3 and 104.8 g/l), and gave also high results of FFase activity (23.01 and 32.42 U/ml). Then, the production of FOS and FFase by repeated batch fermentation with P. expansum immobilized on synthetic fiber was studied, aiming to improve the batch fermentation results. The results obtained in this stage were very promising with FOS yields of 87, 72, and 44 %, in the 3 initial cycles (60 h), respectively; the FFase activity was constant throughout the process (6 cycles, 96 h). Repeated batch fermentation with immobilized cells of P. expansum was found as being a technology with great potential for FOS and FFase production on industrial scaleThe financial support from FCT, the Portuguese Foundation for Science and Technology (research grant SFRH/BPD/38212/2007) is gratefully acknowledged

    Suppression of magnetic order in CaCo 1.86 As 2 with Fe substitution: Magnetization, neutron diffraction, and x-ray diffraction studies of Ca ( Co 1 − x Fe x ) y As 2

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    Magnetization, neutron diffraction, and high-energy x-ray diffraction results for Sn-flux grown single-crystal samples of Ca(Co1x_{1-x}Fex_{x})y_{y}As2_{2}, 0x10\leq x\leq1, 1.86y21.86\leq y \leq 2, are presented and reveal that A-type antiferromagnetic order, with ordered moments lying along the cc axis, persists for x0.12(1)x\lesssim0.12(1). The antiferromagnetic order is smoothly suppressed with increasing xx, with both the ordered moment and N\'{e}el temperature linearly decreasing. Stripe-type antiferromagnetic order does not occur for x0.25x\leq0.25, nor does ferromagnetic order for xx up to at least x=0.104x=0.104, and a smooth crossover from the collapsed-tetragonal (cT) phase of CaCo1.86_{1.86}As2_{2} to the tetragonal (T) phase of CaFe2_{2}As2_{2} occurs. These results suggest that hole doping CaCo1.86_{1.86}As2_{2} has a less dramatic effect on the magnetism and structure than steric effects due to substituting Sr for Ca.Comment: 12 pages, 16 Figure

    An overview of the recent developments on fructooligosaccharide production and applications

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    Over the past years, many researchers have suggested that deficiencies in the diet can lead to disease states and that some diseases can be avoided through an adequate intake of relevant dietary components. Recently, a great interest in dietary modulation of the human gut has been registered. Prebiotics, such as fructooligosaccharides (FOS), play a key role in the improvement of gut microbiota balance and in individual health. FOS are generally used as components of functional foods, are generally regarded as safe (generally recognized as safe status—from the Food and Drug Administration, USA), and worth about 150€ per kilogram. Due to their nutrition- and health-relevant properties, such as moderate sweetness, low carcinogenicity, low calorimetric value, and low glycemic index, FOS have been increasingly used by the food industry. Conventionally, FOS are produced through a two-stage process that requires an enzyme production and purification step in order to proceed with the chemical reaction itself. Several studies have been conducted on the production of FOS, aiming its optimization toward the development of more efficient production processes and their potential as food ingredients. The improvement of FOS yield and productivity can be achieved by the use of different fermentative methods and different microbial sources of FOS producing enzymes and the optimization of nutritional and culture parameter; therefore, this review focuses on the latest progresses in FOS research such as its production, functional properties, and market data.Agencia de Inovacao (AdI)-Project BIOLIFE reference PRIME 03/347. Ana Dominguez acknowledges Fundacao para a Ciencia e a Tecnologia, Portugal, for her PhD grant reference SFRH/BD/23083/2005

    KCNT1- related epilepsy: An international multicenter cohort of 27 pediatric cases

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    ObjectiveThrough international collaboration, we evaluated the phenotypic aspects of a multiethnic cohort of KCNT1- related epilepsy and explored genotype- phenotype correlations associated with frequently encountered variants.MethodsA cross- sectional analysis of children harboring pathogenic or likely pathogenic KCNT1 variants was completed. Children with one of the two more common recurrent KCNT1 variants were compared with the rest of the cohort for the presence of particular characteristics.ResultsTwenty- seven children (15 males, mean age = 40.8 months) were included. Seizure onset ranged from 1 day to 6 months, and half (48.1%) exhibited developmental plateauing upon onset. Two- thirds had epilepsy of infancy with migrating focal seizures (EIMFS), and focal tonic seizures were common (48.1%). The most frequent recurrent KCNT1 variants were c.2800G>A; p.Ala934Thr (n = 5) and c.862G>A; p.Gly288Ser (n = 4). De novo variants were found in 96% of tested parents (23/24). Sixty percent had abnormal magnetic resonance imaging (MRI) findings. Delayed myelination, thin corpus callosum, and brain atrophy were the most common. One child had gray- white matter interface indistinctness, suggesting a malformation of cortical development. Several antiepileptic drugs (mean = 7.4/patient) were tried, with no consistent response to any one agent. Eleven tried quinidine; 45% had marked (>50% seizure reduction) or some improvement (25%- 50% seizure reduction). Seven used cannabidiol; 71% experienced marked or some improvement. Fourteen tried diet therapies; 57% had marked or some improvement. When comparing the recurrent variants to the rest of the cohort with respect to developmental trajectory, presence of EIMFS, >500 seizures/mo, abnormal MRI, and treatment response, there were no statistically significant differences. Four patients died (15%), none of sudden unexpected death in epilepsy.SignificanceOur cohort reinforces common aspects of this highly pleiotropic entity. EIMFS manifesting with refractory tonic seizures was the most common. Cannabidiol, diet therapy, and quinidine seem to offer the best chances of seizure reduction, although evidence- based practice is still unavailable.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154940/1/epi16480_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154940/2/epi16480.pd
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