Characterization Of Cyclodextrins Research Articles

Current trends in molecular modeling methods applied to the study of cyclodextrin complexes

In this review the authors present an overview of different molecular modeling campaigns dealing with the study and characterization of cyclodextrins (CDs) inclusion complexes with applicability to diverse biomedical and technological domains. The aim of this review is to present in a concise manner the new tendencies towards CDs molecular modeling studies in the context of a scientific computing era characterized by detailed and exhaustively validated molecular modeling protocols combined with and enormous and continuously growing computing power. Therefore, the present review covers research efforts reported in the last 5 years, including the simulation of native and modified CDs in a new and more detailed manner than what was possible in the past as well as their inclusion complexes with bioactive molecules studied by detailed protocols and exhaustive free-energy of binding calculations. Also, particular emphasis is devoted to the molecular modeling simulation of CDs included as part of drug delivery matrixes and intelligent nanodevices such as CD-based molecular motors.

Computational Study of Nanosized Drug Delivery from Cyclodextrins, Crown Ethers and Hyaluronan in Pharmaceutical Formulations.

The problem in this work is the computational characterization of cyclodextrins, crown ethers and hyaluronan (HA) as hosts of inclusion complexes for nanosized drug delivery vehicles in pharmaceutical formulations. The difficulty is addressed through a computational study of some thermodynamic, geometric and topological properties of the hosts. The calculated properties of oligosaccharides of D-glucopyranoses allow these to act as co-solvents of polyanions in water. In crown ethers, the central channel is computed. Mucoadhesive polymer HA in formulations releases drugs in mucosas. Geometric, topological and fractal analyses are carried out with code TOPO. Reference calculations are performed with code GEPOL. From HA to HA·3Ca and hydrate, the hydrophilic solvent-accessible surface varies with the count of H-bonds. The fractal dimension rises. The dimension of external atoms rises resulting 1.725 for HA. It rises going to HA·3Ca and hydrate. Nonburied minus molecular dimension rises and decays. Hydrate globularity is lower than O(water), Ca(2+) and O(HA). Ca(2+) rugosity is smaller than for hydrate, O(HA) and O(water). Ca(2+) and O(water) accessibilities are greater than hydrate. Conclusions are drawn on: (1) the relative stability of linear/cyclic and shorter/larger polymers; (2) the atomic analysis of properties allows determining the atoms with maximum reactivity.

Reprint of “Characterization of cyclodextrin containing nanofilters for removal of pharmaceutical residues”

Due to the increasing amount of persistent organic pollutants (POPs) in general and pharmaceutical residues in particular in municipal wastewater, the efficiency of water treatment technologies should be improved. Following the biological treatment of wastewater nanofiltration offers a possible way for the removal of POPs. In this study β-cyclodextrin containing nanofilters having different chemical composition and thickness (1.5–3.5mm) were investigated. For their characterization, their adsorption capacity was determined applying ibuprofen containing model solution and total organic carbon (TOC) analyzer.It could be established that the regeneration of nanofilters with ethanol and the application of inorganic additives (NaCl, NaHCO3, NH4HCO3) increased the adsorption capacity of nanofilters. The best results were achieved with chemical composition of 30m/m% β-cyclodextrin polymer beads and 70m/m% ultra-high molecular weight polyethylene in the presence of 12mmol ammonium hydrogen carbonate/nanofilter.

Characterization of cyclodextrin containing nanofilters for removal of pharmaceutical residues

Due to the increasing amount of persistent organic pollutants (POPs) in general and pharmaceutical residues in particular in municipal wastewater, the efficiency of water treatment technologies should be improved. Following the biological treatment of wastewater nanofiltration offers a possible way for the removal of POPs. In this study β-cyclodextrin containing nanofilters having different chemical composition and thickness (1.5–3.5mm) were investigated. For their characterization, their adsorption capacity was determined applying ibuprofen containing model solution and total organic carbon (TOC) analyzer.It could be established that the regeneration of nanofilters with ethanol and the application of inorganic additives (NaCl, NaHCO3, NH4HCO3) increased the adsorption capacity of nanofilters. The best results were achieved with chemical composition of 30m/m% β-cyclodextrin polymer beads and 70m/m% ultra-high molecular weight polyethylene in the presence of 12mmol ammonium hydrogen carbonate/nanofilter.

Characterization of cyclodextrin modified infrared chemical sensors. Part II. Selective and quantitative determination of aromatic acids

In this paper, the selectivity and sensitivity of cyclodextrin (CD) modified infrared (IR) chemical sensor in detection of aromatic acids in aqueous solutions were reported. To eliminate the interference from water, the technique of attenuated total reflection was employed. By surface treated with CD molecules on the internal reflection elements, the sensors were selective in sensing of aromatic acids compared to aromatic compounds with other functional groups. To facilitate the use of this method for the quantitative analyses of aromatic acids in aqueous solutions, analytical functions were also developed in this work and a linear relationship between analytical responses and concentrations of analytes can be obtained. To optimize the analytical conditions, the factors that influence the IR spectroscopic signals were examined. These factors included response time, CD loadings of the sensors, pH effect on response, regeneration efficiency and stability of sensors. Under the optimal conditions, the detection limits for aromatic acids at a detection time of 2 min can be <100 μg/L. Meanwhile, the dynamic linear range for detection was only ca. two orders of magnitude if direct IR signals were used. Using the analytical function developed in this work, the linearity can be extended up to a concentration of 100 mg/L.