The Influence of Water-soluble Polymers and pH on Hydroxypropyl-β-Cyclodextrin Complexation of Drugs

The effect of water-soluble polymers and ionization of the drug molecules on the cyclodextrin, mainly 2-hydroxypropyl-β-cyclodextrin (HPβCD), solubilization of drugs was investigated. HPβCD has significant solubilizing effect on acetazolamide, prazepam, and sulfamethoxazole in aqueous solutions. All three polymers tested-i.e., hydroxypropyl methylcellulose (HPMC), polyvinylpyrrolidone (PVP), and carboxymethylcellulose-increase the solubilizing effect of HPβCD. The polymers increase the solubilization by increasing the apparent stability constant (K_c of the drug-HPβCD complex. Thus, addition of 0.10% (w/v) HPMC to the aqueous complexation medium results in a 56% increase in K, for the acetazolamide-HPβCD complex and a 200% increase in K_c for the prazepam-HPβCD complex. Addition of 0.25% (w/v) PVP to the complexation medium results in a 138% increase in K for the sulfamethoxazole-HPβCD complex. The HPβCD solubilization of the drugs can also be improved by ionization of the drug molecule through pH adjustments. However, larger improvements of the HPβCD solubilization are obtained when both methods are used simultaneously compared to when either method is used separately.     

Cyclodextrin–poloxamer aggregates as nanocarriers in eye drop formulations: dexamethasone and amphotericin B

In this present study cyclodextrin (CD)–poloxamer aggregates were characterized and developed as ophthalmic drug carriers. The combined effect of γCD/2-hydroxypropyl-γCD (HPγCD) mixtures and poloxamer on solubilization and permeability of two model drugs, dexamethasone (Dex) and amphotericin B (AmB), was investigated. The CD–poloxamer interaction and complex aggregation were examined by ¹H nuclear magnetic resonance (¹H-NMR), their solubilizing ability by high-performance liquid chromatography, and their particle size determined by dynamic light scattering and transmission electron microscopy. Formulations containing either 1.5% w/v Dex or 0.15% w/v AmB in eye drop suspensions containing various γCD/HPγCD ratios and poloxamer 407 (P407) were prepared. The solubility of the drugs, surface tension and hemolytic effect of the eye drops and drug permeation from selected formulations were determined. The ¹H-NMR study showed that P407 formed inclusion complex with CDs by inserting its poly(propylene oxide) segment into the CD cavity. P407 and γCD interacted with each other to form nanosized aggregates, and the observed concentration of dissolved γCD and P407 progressively decreased with increasing γCD and P407 concentrations. Including a high proportion of HPγCD improved the drug solubilization and reduced the hemolytic effect. The surface tension of the formulations decreased with increasing P407 concentration. Furthermore, increasing P407 content in the formulations enhanced formation of complex aggregates with consequent slower drug release. It was concluded that the drug/γCD/HPγCD complex was stabilized by P407 through formation of multi-component aggregates. Thus, CD–poloxamer aggregates are self-assembled nanocarriers from which drug delivery characteristics can be adjusted by changing the γCD/HPγCD/P407 ratios.     

Processing of Aluminum Dross: The Birth of a Closed Industrial Process

This is the history of a modern aluminum dross recycling company, from its beginnings in the last years of the twentieth century to the present day. The vision of the founders was to build a local recycling plant and take full responsibility for sensitive environmental issues by recycling aluminum dross locally rather than shipping it abroad. The paper tells the history of the company from the environmental perspective, and gives an overview of some of the challenges and the decisions that followed from this vision, for instance the selection of technology. The company developed a closed industrial process for the recycling of aluminum dross, and the paper discusses some of their laboratory experiments and industrial trials. An important milestone has now been reached as the process in its present form is recognized by the environmental authorities in the country. Furthermore, it seems realistic that in the near future the final product from this process will be comparable to the product delivered in the processing of salt cake in specialized chemical plants, but at a fraction of the cost.     

Maximizing industrial infrastructure efficiency in Iceland

As a consequence of the increasing aluminum production in Iceland, local processing of aluminum skimmings has become a feasible business opportunity. A recycling plant for this purpose was built in Helguvik on the Reykjanes peninsula in 2003. The case of the recycling plant reflects increased concern regarding environmental aspects of the industry. An interesting characteristic of this plant is the fact that it is run in the same facilities as a large fishmeal production installation. It is operated by the same personnel and uses—partly—the same equipment and infrastructure. This paper reviews the grounds for these decisions and the experience of this merger of a traditional fish melting industry and a more recent aluminum melting industry after 6 years of operation. The paper is written by the original entrepreneurs behind the company, who provide observations on how the aluminum industry in Iceland has evolved since the starting of Alur’s operation and what might be expected in the near future.     

Serum Proteomics in Patients with Head and Neck Cancer: Peripheral Blood Immune Response to Treatment

In this real-world study, the aims were to prospectively evaluate the expression of inflammatory proteins in serum collected from head and neck cancer patients before and after treatment, and to assess whether there were differences in expression associated with treatment modalities. The mixed study cohort consisted of 180 patients with head and neck cancer. The most common tumor sites were the oropharynx (n = 81), the oral cavity (n = 53), and the larynx (n = 22). Blood tests for proteomics analysis were carried out before treatment, 7 weeks after the start of treatment, and 3 and 12 months after the termination of treatment. Sera were analyzed for 83 proteins using an immuno-oncology biomarker panel (Olink, Uppsala, Sweden). Patients were divided into four treatment groups: surgery alone (Surg group, n = 24), radiotherapy with or without surgery (RT group, n = 94), radiotherapy with concomitant cisplatin (CRT group, n = 47), and radiotherapy with concomitant targeted therapy (RT Cetux group, n = 15). For the overall cohort, the expression levels of 15 of the 83 proteins changed significantly between the pretreatment sample and the sample taken 7 weeks after the start of treatment. At 7 weeks after the start of treatment, 13 proteins showed lower expression in the CRT group compared to the RT group. The majority of the inflammatory proteins had returned to their pretreatment levels after 12 months. It was clearly demonstrated that cisplatin-based chemoradiation has immunological effects in patients with head and neck cancer. This analysis draws attention to several inflammatory proteins that are of interest for further studies.     

Deterministic annealing with Potts neurons for multi-robot routing

A deterministic annealing (DA) method is presented for solving the multi-robot routing problem with min–max objective. This is an NP-hard problem belonging to the multi-robot task allocation set of problems where robots are assigned to a group of sequentially ordered tasks such that the cost of the slowest robot is minimized. The problem is first formulated in a matrix form where the optimal solution of the problem is the minimum-cost permutation matrix without any loops. The solution matrix is then found using the DA method is based on mean field theory applied to a Potts spin model which has been proven to yield near-optimal results for NP-hard problems. Our method is bench-marked against simulated annealing and a heuristic search method. The results show that the proposed method is promising for small-medium sized problems in terms of computation time and solution quality compared to the other two methods.

     

Structure–function relationships of fullerene esters in polymer solar cells: unexpected structural effects on lifetime and efficiency

We report both transport measurements and spectroscopic data of polymer/fullerene blend photovoltaics using a small library of fullerene esters to correlate device properties with a range of functionality and structural diversity of the ester substituent. We observe that minor structural changes can lead to significant and surprising differences in device efficiency and lifetime. For example we have found that isomeric R‐groups in the fullerene ester‐based devices we have studied have dramatically different efficiencies. The characteristic lifetimes derived from both transport and spectroscopic measurements are generally comparable; however, some more rapid effects in specific fullerene esters are not observed spectroscopically. It is apparent from our results that each fullerene derivative requires re‐optimization to reveal the best device performance. Furthermore we conclude that a library approach is essential for evaluating the effects of structural differences in the constituent molecules and serves as important device optimization method that is not being currently employed in photovoltaic investigations. Copyright © 2015 John Wiley & Sons, Ltd.     

Dermal delivery of ETH-615, a zwitterionic drug

ETH-615 is an amphoteric drug that forms a water-insoluble zwitterion at intermediate pH values. Increasing the aqueous solubility of ETH-615 through cyclodextrin complexation did not enhance transdermal delivery of the drug from saturated aqueous solutions. However, increasing the lipophilicity of the drug through masking of the anionic group with a pro-moiety increased the dermal and transdermal delivery of the drug. Furthermore, masking the anionic group enhanced the chemical stability of the drug, resulting in significant improvement of the shelf life of the drug in both aqueous and nonaqueous solutions.     

The feasibility of using geothermal energy in hydrogen production

A feasibility study exploring the use of geothermal energy in hydrogen production is presented. It is possible to use a thermal energy to supply heat for high temperature electrolysis and thereby substitute a part of the relatively expensive electricity needed. A newly developed HOT ELLY high temperature steam electrolysis process operates at 800 – 1000°C. Geothermal fluid is used to heat fresh water up to 200°C steam. The steam is further heated to 900°C by utilising heat produced within the electrolyser. The electrical power of this process is reduced from 4.6 kWh per normalised cubic meter of hydrogen (kWh/Nm³ H₂) for conventional process to 3.2 kWh/Nm³ H₂ for the HOT ELLY process implying electrical energy reduction of 29.5%. The geothermal energy needed in the process is 0.5 kWh/Nm³ H₂. Price of geothermal energy is approximately 8–10% of electrical energy and therefore a substantial reduction of production cost of hydrogen can be achieved this way. It will be shown that using HOT ELLY process with geothermal steam at 200°C reduces the production cost by approximately 19%.     

Effect of various marine lipids on transdermal drug delivery--in vitro evaluation

The effects of several marine lipids on the penetration of hydrocortisone and nitroglycerin through excised hairless mouse skin have been studied. Fatty acid extracts obtained by hydrolysis of Portuguese dog-fish-liver-oil or by hydrolysis of cod-liver-oil were shown to be effective skin penetration enhancers. Phospholipid obtained from squid was also shown to be effective enhancer. However, the enhancing effect of the marine products could generally be associated with their content of free unsaturated fatty acids. The fatty acid extract obtained from cod-liver-oil caused insignificant skin irritation when incorporated into an ointment base and applied to human skin.