Spray-dried nanoparticle-loaded pectin microspheres for dexamethasone nasal delivery

Abstract

In this study, we present the development of an innovative dry powder dexamethasone (Dex) nasal delivery system comprising Dex-loaded lipid/alginate nanoparticles incorporated within pectin microspheres (Dex/NPs-loaded pectin microspheres; DNM). DNM microspheres were characterized by the mean diameter of 2.76?±?0.10?µm, zeta-potential of –36.2?±?1.1?mV, and drug loading of 3.3?±?0.3%. The morphology study revealed irregular microsphere surface forming external voids. In contact with simulated nasal fluid, DNM microspheres demonstrated desirable property of moderate swelling and ensured stronger mucoadhesion compared with conventional Dex-loaded pectin microspheres. The strategy of Dex incorporation within the lipid/alginate NPs resulted in prolonged Dex release in relation to Dex being directly entrapped within the conventional pectin microspheres. DNM microspheres showed excellent biocompatibility and rendered Dex permeation across the selected epithelial cell model similar to that of Dex solution. In conclusion, balanced biopharmaceutical properties of the proposed nasal Dex delivery system provides the potential for prolonged contact time with nasal mucosa, prolonged therapeutic effect, and improved patient compliance.     

Application of an ultrasound field in chemical cleaning of ceramic tubular membrane fouled with whey proteins

Chemical cleaning of a severe in-pore-fouling may be improved by applying an ultrasound (US) field in a cleaning-in-place (CIP) system, under both the batch and flow conditions. This study is concerned with the cleaning of a 200-nm ceramic membrane, fouled with whey proteins, in an US field of relatively low frequency of 35 kHz, without applying a transmembrane pressure (TMP) and cross-flow velocity. Two types of cleaning agent solutions of different concentrations were applied: alkali (NaOH) and a mixture of commercial detergents (P3-Ultrasil 67 and 69) at a sonication time of 30 min. It was found that the application of US was less effective in the combination with sodium hydroxide than with the mixture of commercial detergents. Using US in a mixture of 0.25% w/w P3-Ultrasil 67 and 0.4% w/w P3-Ultrasil 69 resulted in the highest flux recovery of 86.5 ± 2.9%, after 30 min of sonication, and produced an overall efficiency of 96.3 ± 0.4%, after the second sonication. It was concluded that the application of the US field in a batch mode, combined with the mentioned chemical agents, can significantly improve the cleaning efficiency.     

An electromagnetism metaheuristic for solving the Maximum Betweenness Problem

In this paper we present an electromagnetism (EM) metaheuristic for solving NP hard Maximum Betweenness Problem (MBP). A new encoding scheme with appropriate objective functions is implemented. Specific representation of the individuals enables the EM operators to explore the searching space in a way that achieves high quality solutions. An effective 1-swap based local search procedure improved by the specific caching technique is performed on each EM point. The algorithm is tested both on real and artificial instances from the literature. Experimental results show that the proposed EM approach achieves all previously known optimal solutions, except one, and achieves the best-known solutions or outperforms other approaches on all large-scale instances, except two. Provided statistical analysis indicates that the EM approach is significantly better than other approaches.     

Me-DLC films as material for highly sensitive temperature compensated strain gauges

In technical applications strain gauges are widely used. Apart from conventional polymer foil based strain gauges that are glued to the work piece surface, sputtered strain gauges are already commercially used in special applications. Those sputter strain gauges are typically made of NiCr alloy and the sensor layer is as sensitive to strain as the ones used in the glued strain gauges with a gauge factor of 2, but neglecting problems of creeping and swelling of the involved polymer materials. Diamond-like carbon (DLC) films offer significantly higher strain sensitivity, but usually they are also very sensitive to temperature effects. Using metal doped diamond-like carbon (Me-DLC), higher strain sensitivity than conventional metal based systems, in combination with thermal compensation, is possible. The influence of different process parameters on the gauge factor and temperature coefficient of resistance (TCR) of DLC and Me-DLC films produced in industrial sputtering systems was investigated. Gauge factors up to 13 in combination with a high negative TCR in the range of a few thousand ppm/K were reached with sputtered DLC films. The substrate bias voltage in particular showed a strong influence on the resulting gauge factor of the films. For Me-DLC films different deposition methods (dc and rf sputtering) and various doping metals (Ag, Ni, Ti, and W) were investigated. Using dc sputtering of the Me-DLC films only Ni-DLC showed gauge factors slightly higher than 2. Furthermore, only for Ni-DLC zero crossing of the TCR was observed by variation of the metal content. Using rf excitation especially Ni-DLC films showed gauge factors exceeding values of 15 in combination with a TCR close to zero.     

The accommodative convergence/accommodation (AC/A) and near convergence/distance (NC/D) ratios in esotropia

An adequate respiratory protective device should keep the concentration of the pollutant inside the facepiece below the appropriate occupational exposure limit. Filtering respirators will not provide adequate protection if the device fails in an atmosphere which is immediately dangerous to life or health (IDLH). It has therefore been suggested that in contaminant concentrations above an IDLH level it is more appropriate to select breathing apparatus with an emergency breathing facility. In this paper IDLH levels published by the US National Institute of Occupational Safety and Health have been compared with UK occupational exposure limits. For some substances there was a relatively small difference between the IDLH level and the short-term occupational exposure limit (STEL). The median ratio of the IDLH level to the STEL was 10 for gases and vapours and 50 for aerosols. For almost half the substances with UK occupational exposure limits there is no IDLH value. It is concluded that the published IDLH concentrations are, on their own, an insufficient basis for selecting breathing apparatus over a filtering respirator. It is equally important to consider the likelihood that a filtering device may fail catastrophically since this determines the risk from wearing a respirator in an IDLH atmosphere. More emphasis should be placed on the control of potentially high exposure levels by means other than respiratory protection.     

Microbial and physicochemical succession in fermented sausages produced with bacteriocinogenic culture of Lactobacillus sakei and semi-purified bacteriocin mesenterocin Y

The influence of the bacteriocinogenic culture Lactobacillus sakei (10⁵/g) and semi-purified bacteriocin mesenterocin Y (2560 AU/kg) on the safety and quality of traditional Croatian fermented sausages was investigated. The addition of Lb. sakei and/or mesenterocin Y reduced microbial counts (P < 0.05) in the final products. After 28 days of ripening, coagulase-negative cocci decreased 1.5–2.0 log, yeasts 1.2–1.4 log and enterococci 1.7–2.7 log. In the case of the addition of Lb. sakei, the lactic acid bacteria count was significantly (P < 0.05) higher at day 7 of ripening, and was accompanied by a lower pH and a higher amount of lactic acid (P < 0.05). In the final product the amount of acetic acid was significantly lower. More intensive proteolysis and an increase in ammonia content were found at the beginning of fermentation, and in the second phase of ripening in the control samples, respectively. The free fatty acid concentration was significantly lower during the entire ripening process compared to the control (P < 0.05). Semi-purified mesenterocin Y did not affect the sensory properties of the sausages, whilst the addition of Lb. sakei enhanced them.     

Total and individual carotenoids and phenolic acids content in fresh,refrigerated and processed spinach (Spinacia oleracea L.)

The carotenoid and phenolic acid contents in fresh, stored and processed (blanched, frozen and boiled) spinach were comparatively determined by spectrophotometric and HPLC analyses. The major carotenoids identified after HPLC analysis in saponified samples were lutein (37–53 μg/kg), β-carotene (18–31 μg/kg), violaxanthin (9–23 μg/kg) and neoxanthin (10–22 μg/kg). These carotenoids were all affected by storage and/or heating. The content of carotenoids was best preserved after storage for one day at 4 °C.     

Inulin-based emulsion-filled gel as a fat replacer in prebiotic- and PUFA-enriched dry fermented sausages

In order to produce fermented sausages with prebiotic fibre and improved fatty acid composition, 16% of pork back fat was replaced with inulin gelled suspension (I) and inulin linseed oil gelled emulsion (IO). Physico-chemical analysis, fatty acid profiles, lipid oxidation, microbiological, textural, colour and sensory analysis were carried out. The fat content was lower in I (31.38%) and IO (35.36%) modified sausages compared to control (44.37%) (P < 0.05). IO sausages had lower SFA and MUFA and higher PUFA content with an improved n-6/n-3 ratio (2.23) (P < 0.05) and α-linolenic acid increment (5.74 g per 100 g). Reformulation led to decrease in springiness, chewiness and hardness and increase in adhesiveness of the sausages. Modified sausages had lower L* and higher a* values, while b* values of I sausages did not differ compared to control sausages. Modified sausages were acceptable regarding all sensory attributes. Lipid oxidation parameters showed higher susceptibility to oxidation and lipolysis in IO sausages.