Hot-melt coating technology. I. Influence of Compritol 888 Ato and granule size on theophylline release

The aim of this work was to study the influence of theophylline granule size and the percentage of Compritol® 888 Ato on in vitro drug release from granules and tablets. The granules were coated in a fluidized bed apparatus. The dissolution profiles of these granules differed from those of granules coated with classical agents, and there were also differences between the various sieve fractions studied. Drug release was characterized by a rapid-release phase, followed by a slow-release phase. Results indicate that theophylline release can be controlled by controlling granule size. Inspection of the appearance of the tablets at the end of the dissolution test revealed that all tablets containing Compritol 888 Ato remained intact. This indicated that the Compritol 888 Ato used in the tablet formulation created an inert matrix through which the drug diffused. It was found that the Higuchi relationship of linear square root of time was the best model to describe the release kinetics of the drug from tablets. This also confirmed that a matrix diffusion-controlled mechanism was operative. Given the difference between the dissolution profiles of the granules and the tablets, it was concluded that this matrix is formed during compression.     

Development of 400 microm pellets by extrusion-spheronization: application with Gelucire 50/02 to produce a "sprinkle" form

The aim of this study was to develop monodimensional, spherical particles of 400 µm by extrusion-spheronization. An Alexanderwerk GA65 cylinder extruder with two counter-rotating rollers associated with a Caleva model 15 spheronizer were used. The study was made with an auxiliary substance of fatty consistency and with amphiphilic properties: Gelucire 50/02. The plasticity of the mass can be deduced using a piston extruder. Pellet quality can be determined by particle-size analysis and shape estimation by microscopy. Modifications to the cylinders and the extruder itself are required for feasibility studies of extruded materials of 400 µm. The horizontal plate of the spheronizer had to be adapted to take into account the small size of the extruded materials. For the chosen auxiliary substance, Gelucire 50/02, the formulation of the wet mass to be extruded and the conditions required to obtain this mass were defined. The results show the feasibility of 400 µm pellets with Gelucire 50/02. At least 90% of the pellets have a particle size of between 250 µm and 500 µm and particle shape is acceptable. In this form the dose can be adapted to individual patients. After proving the feasibility of 400 µm spheroids of Gelucire 50/02, the association of a drug with it was considered.     

植物油的氧化及其对淬火特性的影响

传统上,矿物油是常用淬火剂中最重要的一类淬火剂。然而,它们在本质上缺乏环保性,又有毒性,再从长期低价供应角度考虑,有必要寻找新的替代介质。石油制品油的淬火特性与其成分很有关系,因而受其氧化降解性能的限制。由于不断暴露在钢与油接触面问相对较高的温度中,石油制品油遭受热降解和氧化降解,使得其淬火特性发生明显变化。因此,淬火特性是任何一种可选择的淬火介质都必须要检验的一个非常重要的性能参数。可供选择的一类液态物质为植物油,它们具有典型的生物降解特性并且无毒。然而,植物油具有相对较差的抗氧化稳定性能,因此测定氧化对其淬火特性的潜在影响具有重要意义。本文报导的结果仅是这项巨大研究中的第一步,在这项工作中,对不受禁止的植物油的试验是在实验室设备上进行的,以前报告的促使石油制品油早期氧化的过程接近实际使用条件。依照ASTM D 6200标准,使用粘度计、红外线分光镜、^13CMR分光镜以及冷却曲线特性测定方法对所研究的液态植物油进行了性能检测并和典型的石油制品油作了成分比较。所得的结果表明,作为淬火介质,植物油是有前景的石油制品油的替代品,但在商业上要可行,同时必须使用适当的抗氧化剂。     

Grid-Tied PV-BES system based on modified bat algorithm-FLC MPPT technique under uniform conditions

Neural Computing and Applications - Grid-connected photovoltaic (PV) systems play an important role in reducing emissions resulting from conventional fossil-fuel-based power plants. However, in...     

Aflatoxins: Occurrence in red chilli and control by gamma irradiation

Chilli is one of the valuable spices commercialised globally, added as condiments in various cuisines and is easily susceptible to aflatoxin contamination (produced mainly by Aspergillus flavus) during pre- and post-harvesting stages. The important factors such as temperature, moisture content and humidity affect the growth of fungi producing aflatoxins. Chillies contaminated with aflatoxins could be carcinogenic and thus can pose a threat to the general population leading to the loss of international trade market. Therefore, to overcome this problem, there is a need for some effective and novel technologies such as gamma irradiation. Gamma irradiation minimises the toxicological effects of aflatoxins by inhibiting the growth as well as the proliferation of Aspergillus species. In this work, the natural occurrence of aflatoxins including the contribution of gamma irradiation on either eliminating or controlling the aflatoxins in red chilli is reviewed.     

A deep multimodal system for provenance filtering with universal forgery detection and localization

Multimedia Tools and Applications - Traditional multimedia forensics techniques inspect images to identify, localize forged regions and estimate forgery methods that have been applied. Provenance...     

Thermal performance study of a vacuum integrated solar storage collector (ISSC) with compound parabolic concentrator (CPC)

This paper deals with the energy performance of a new integrated solar storage collector (ISSC) with compound parabolic concentrator (CPC) conceived in the Thermal Process Laboratory in CRTEn Borj Cedria (North of Tunisia). The novelty in this system is the use of transparent vacuum insulation in the annulus between double half-Cylindrical Plexiglass, and the use of automated nocturnal insulation system, which suppresses heat loss during night. Also, the system is equipped with a mobile support permitting to have many collector orientations toward south, east-south, and west-south in order to maximize the incident solar flux. The experimental study of the ISSC system showed that the thermal loss coefficient of ISSC system is equal to 6.16 W/K for ISSC without nocturnal insulation and without vacuum, 4.69W/K for ISSC without nocturnal insulation and with vacuum, and 4.00 W/K for ISSC with nocturnal insulation and with vacuum. The thermal efficiency of the solar collector is equal to 42.92% for ISSC system fixed without vacuum, 45.95% for ISSC system fixed with vacuum, and 50.56% for ISSC system mobile with vacuum. In order to determine the long-term performance of the vacuum ISSC with CPC, the TRNSYS simulations were carried out by using the component modules modeling the ISSC with CPC concentrator (type 74 and type 60f). Comparison between experimental and predicted results for the temperature difference inside the storage tank during 3 days of January showed reasonable agreement. The numerical results for the ISSC system showed that the annual total energy collected (solar) and auxiliary energy were about 4670 and 1561 MJ, respectively. The annual total auxiliary energy represents about 33.4% of the annual total energy collected (solar). During the summer months (June, July, and August), no auxiliary is needed and the solar fraction (SF) is equal to 100%, where as the annual average SF is about 75%.     

Fabrication and Catalytic Characterization of Laccase-Loaded Calcium-Alginate Beads for Enhanced Degradation of Dye-Contaminated Aqueous Solutions

Catalysis Letters - Engineered laccases represent an eco-friendlier and robust biocatalytic tool for the treatment of dye-harboring textile wastewater. This study investigates the immobilization of...     

Nanocellulose-based fibres derived from palm oil by-products and their in vitro biocompatibility analysis

Abstract

Fibres with nanocellulose isolated from oil palm empty fruit bunches (OPEFBs) were produced. Nanocellulose and PVA-nanocellulose fibres were prepared by wet spinning in an acetone coagulation bath without drawing. The addition of nanocellulose was varied from 10% to 30%, to reveal the beneficial effects of nanocellulose content on the properties of produced spun-fibres. Higher concentration of nanocellulose increased the stiffness of spun-fibres. PVA and PVA-bacterial cellulose fibres were also produced as a control and for comparison, respectively. The nanocellulose fibre formed a compact structure, while PVA fibres had hollow structures. The effect of the produced spun-fibres on the biocompatibility of calf pulmonary artery endothelial cells was assayed by an MTT test. Based on the MTT assay the addition of nanocellulose increased the percentage of cell viability of the obtained spun-fibres slightly. These results point towards the use of sustainable sources of nanocellulose as a beneficial and biocompatible fibre material.