Novel self-assembled mesalamine–sucralfate complexes: preparation,characterization, and formulation aspects

Two well-known active agents, mesalamine (MES) and sucralfate (SUC), were investigated for possible utilization as fixed-dose combination product. The anti-inflammatory action of MES in association with bioadhesiveness and mucosal healing properties of SUC were considered promising for the development of a new compound containing both molecules, aimed as an improved treatment of ulcerative colitis. The present study investigates the capacity of the two active agents to interact and generate a new and stable entity via self-assembling. Spray-drying was used to co-process the two active principles from an aqueous mixture where the ratio MES:SUC was in the range 25:75, 50:50, and 75:25. The structural data (X-Ray, FTIR, SEM, DSC, and ¹H NMR) have shown that MES and SUC are interacting leading to complexes with properties differing from those of each separate active agent and from their physical blends. ¹H NMR results indicated that complexation occurred when the aqueous suspensions of drugs were mixed, prior to spray-drying. Drug–drug self-assembling was the driving mechanism in the formation of the new entity. Based on the structural data, a hypothetical structure of the complex was proposed. Co-processing of MES and SUC represents a simple and useful procedure to prepare new self-assembled compounds by valorizing the ionic interactions between the two entities. Preliminary studies with oral solid dosage forms based on MES–SUC complexes tested in vitro have shown a controlled MES release, opening the perspective of a new colon-targeted delivery system and a novel class of compounds with therapeutic application in inflammatory bowel diseases.     

Electroseparation of an antibacterial peptide fraction from snow crab by-products hydrolysate by electrodialysis with ultrafiltration membranes

Recently, a snow crab by-products hydrolysate has demonstrated antibacterial properties due to a peptide with a molecular weight of about 800 Da, but only at high concentration. Consequently, peptide hydrolysate has been fractionated to obtain peptides in a more purified form. The aim of this work was to separate a snow crab by-products hydrolysate by electrodialysis with ultrafiltration membranes (EDUF). EDUF, which allows separation of molecules according to their charges and molecular weights, was used to recover and concentrate the active antibacterial fraction. Two different ultrafiltration membranes (20 and 50 kDa) and two electrical field strengths (2 and 14 V/cm) were used as separation parameters. After EDUF separation, the 300-600 Da peptide molecular weight range was the most recovered with an abundance of 94%. Moreover, fractionation at 14 V/cm with ultrafiltration membranes of 50 kDa allowed the recovery of an anionic fraction which showed antibacterial properties on Escherichia coli ATCC 25922 and Listeria innocua HPB 13.     

Computer Simulation of a Living Cell: Metabolic Control System Experiments

Abstract

This paper reports on some interesting experiments performed on a simulated model of a living cell. The basic model is that of Weinberg [35] and the underlying techniques employed are described by Zeigler and Weinberg [41]. The cell was subjected to step changes in its nutrient environment.     

In-Situ Analyzing the Influence of Thermoelectromagnetic Convection on the Nucleation Ahead of the Advancing Interface During Directional Solidification

Sn-3wt%Pb alloy was directionally solidified without and with a 0.08T transverse magnetic field(TMF),and real-time recorded by in-situ synchrotron X-ray imaging.Results indicate that TMF shortened the distance from the location of nucleation to the advancing interface,and accelerated the growth rate of the equiaxed crystal,which caused the columnar-to-equiaxed transition(CET)finally.The thermoelectromagnetic convection(TEMC)in front of the interface and around the crystal’s dendritic branch should respond to changes of the distance and the growth rate.     

Benchmarking flexible job-shop scheduling and control systems

Benchmarking is comparing the output of different systems for a given set of input data in order to improve the system’s performance. Faced with the lack of realistic and operational benchmarks that can be used for testing optimization methods and control systems in flexible systems, this paper proposes a benchmark system based on a real production cell. A three-step method is presented: data preparation, experimentation, and reporting. This benchmark allows the evaluation of static optimization performances using traditional operation research tools and the evaluation of control system's robustness faced with unexpected events.