Preparation and characterization of the inclusion complex of Ofloxacin with β-CD and HP-β-CD

PCL/Yam Polysaccharide nanofibrous membranes loaded with self-assembled HP-β-CD/ECG inclusion complexes for food packaging

In this study, Polycaprolactone (PCL)/Yam Polysaccharide (YP) fiber membranes loaded the ultrasound-mediated assembly of 2-Hydroxypropyl-β-cyclodextrin (HP-β-CD)/Epicatechin gallate (ECG) inclusion complexes were prepared by electrospinning technology for food packaging. Morphology, infrared spectroscopy and X-ray diffraction results showed that the inclusion complexes were successfully assembled. With the addition of inclusion complexes, the average diameter of the fibers increased from 2480.96 to 10179.12 nm, the crystallinity decreased, the thermal stability improved, the hydrophilicity enhanced, and the water vapor permeability enhanced. Meanwhile, thermogravimetry and differential scanning calorimetry results showed that the inclusion complexes formed hydrogen bonds between the fibers, which improved the thermal stability, but the mechanical behavior suffered a certain loss. In addition, the fiber membrane could continuously release ECG within 240 h, which showed excellent antibacterial effects both in vitro and in vivo. These results indicated that the fiber film developed based on electrospinning had a broad application prospect in food packaging.

Influence of different anionic polysaccharide coating on the properties and delivery performance of nanoliposomes for quercetin

Nanoliposome is an effective delivery system for polyphenols, whereas it always suffers from low electrostatic stability and oxidation of lipid membranes. Here, different charged anionic polysaccharides including carrageenan (-62.67 ± 1.85 mV), trehalose (-20.73 ± 1.42 mV), and pectin (-4.47 ± 0.38 mV) were used as coating material to improve the stability of nanoliposomes. Results showed that carrageenan coating greatly inhibited aggregation and fusion of nanoliposome. The coating of the higher charged polysaccharides produced the more hydrogen bonds and made the inner chains of lipid molecules more compact, thus improving the rigidity of the membrane and thermal stability. In addition, the polysaccharide coating effectively reduced the lateral diffusion within the membrane and the propagation rate of oxidation reaction. The aim of this study is to investigate the effect of anionic polysaccharides with different charges on coated nanoliposomes, provide reference for the delivery of quercetin.

Cyclodextrin-assisted SERS determination of fluoroquinolone antibiotics in urine and blood plasma

This paper describes the use of cyclodextrins (CDs) to improve the determination of fluoroquinolone antibiotics in human body fluids using surface-enhanced Raman spectroscopy (SERS). CDs were used to (i) prepare the CD-SERS substrate (synthesis and stabilization of silver nanoparticles), (ii) increase the sensitivity of the assay by enhancing the interaction between analyte molecules and the substrate, and (iii) improve the analysis accuracy by reducing the interaction between the substrate and endogenous components of body fluids. Two native CDs (α-CD and β-CD) and two of their derivatives with hydroxypropyl groups were tested, and the best results were obtained with CD-SERS substrate prepared using native β-CD. The CD-SERS assay has been developed and optimized for the determination of commonly used and structurally related fluoroquinolones (ciprofloxacin, norfloxacin, pefloxacin, and levofloxacin) in urine and blood plasma samples. Importantly, the non-significant difference in the interaction of the CD-modified SERS substrate with various fluoroquinolones has been successfully used to develop a versatile assay suitable for the analyte-class-specific analysis. Calibration plots were obtained for concentration ranges suitable for the determination of the antibiotics in urine (50-500 μg mL^-1) and blood plasma (1-6 μg mL^-1). The following figures of merit were obtained (for urine and blood plasma, respectively): RSD values are ≤15% and ≤23%, LOD values are 2.9-5.8 and 0.05-0.34 μg mL^-1, recovery ranges are 96-105% and 91-111%. In addition, the influence of excessive concentrations of some main endogenous components of the body fluids on the analytical signal was studied. This step was used to evaluate possible limitations of the assay associated with the deviation of the composition of the body fluid matrix. Therefore, accounting for the short analysis time (≤15 min) and the use of a portable Raman spectrometer, the proposed assay can be suggested for therapeutic drug monitoring in hospitals.

Preparation, Characterization and Molecular Dynamics Simulation of Rutin-Cyclodextrin Inclusion Complexes

Rutin is a natural flavonoid that carries out a variety of biological activities, but its application in medicine and food is limited by its water solubility. One of the classical methods used to enhance drug solubility is encapsulation with cyclodextrins. In this paper, the encapsulation of different cyclodextrins with rutin was investigated using a combination of experimental and simulation methods. Three inclusions of rutin/beta-cyclodextrin (β-CD), rutin/2-hydroxypropyl beta-cyclodextrin (HP-β-CD) and rutin/2,6-dimethyl beta-cyclodextrin (DM-β-CD) were prepared by the freeze-drying method, and the inclusions were analyzed using Fourier infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), differential scanning calorimetry (DSC) and ultraviolet-visible spectroscopy (UV) to characterize and demonstrate the formation of the inclusion complexes. Phase solubility studies showed that rutin formed a 1:1 stoichiometric inclusion complex and significantly increased its solubility. β-CD, HP-β-CD, DM-β-CD, rutin and the three inclusion complexes were modeled by using MS2018 and AutoDock 4.0, and molecular dynamics simulations were performed to calculate the solubility parameters, binding energies, mean square displacement (MSD), hydrogen bonding and radial distribution functions (RDF) after the equilibration of the systems. The results of simulation and experiment showed that rutin/DM-β-CD had the best encapsulation effect among the three cyclodextrin inclusion complexes.

Cyclodextrin Inclusion Complexes with Antibiotics and Antibacterial Agents as Drug-Delivery Systems—A Pharmaceutical Perspective

Cyclodextrins (CDs) are a family of cyclic oligosaccharides, consisting of a macrocyclic ring of glucose subunits linked by α-1,4 glycosidic bonds. The shape of CD molecules is similar to a truncated cone with a hydrophobic inner cavity and a hydrophilic surface, which allows the formation of inclusion complexes with various molecules. This review article summarises over 200 reports published by the end of 2021 that discuss the complexation of CDs with antibiotics and antibacterial agents, including beta-lactams, tetracyclines, quinolones, macrolides, aminoglycosides, glycopeptides, polypeptides, nitroimidazoles, and oxazolidinones. The review focuses on drug-delivery applications such as improving solubility, modifying the drug-release profile, slowing down the degradation of the drug, improving biological membrane permeability, and enhancing antimicrobial activity. In addition to simple drug/CD combinations, ternary systems with additional auxiliary substances have been described, as well as more sophisticated drug-delivery systems including nanosponges, nanofibres, nanoparticles, microparticles, liposomes, hydrogels, and macromolecules. Depending on the desired properties of the drug product, an accelerated or prolonged dissolution profile can be achieved when combining CD with antibiotics or antimicrobial agents.

Spectroscopic and computational insights into theophylline/β-cyclodextrin complexation: inclusion accomplished by diverse methods

Current scenario in asthmatic prevalence worldwide calls for a facile, cost-effective, and energy efficient methodology to formulate the potent bronchodilator, theophylline (THP), into an effective dosage forms. Since the uses of THP are severely impeded by its poor aqueous solubility and low bioavailability, solid inclusion complexes (ICs) of THP in β-cyclodextrin (β-CD) were prepared to overcome the limitations. The ICs were developed by conventional methods and also by microwave irradiation method, which is environmentally more benign and requires lesser reaction time. The complexation phenomenon was effectual by the co-precipitation, freeze-drying, and microwave methods as affirmed from various spectroscopic analyses. ¹H NMR and molecular docking studies illustrated the total inclusion of THP into β-CD cavity. Better efficacy of the microwaved product was witnessed in terms of drug content, dissolution, and anti-biofilm activities. Thus microwave irradiation can be utilised as a naive and economical methodology to design β-CD-THP dosage formulations.

Preparation and characterization of cyanazine–hydroxypropyl-beta-cyclodextrin inclusion complex

Due to its poor water solubility, the herbicide cyanazine is usually dissolved in organic reagents when used, which poses a great threat to the environment. Poor water solubility also causes limited herbicidal activity. In our study, the water solubility of cyanazine was increased by forming a cyanazine/hydroxypropyl beta-cyclodextrin (HPβCD) inclusion complex. The formation of the inclusion complex was confirmed by FT-IR, XRD, SEM and other characterization methods. Phase solubility study showed that HPβCD could improve the water solubility of cyanazine. Thermogravimetric analysis indicated that the thermal stability of cyanazine was improved by forming inclusion complex and the biological activity test showed that better herbicidal activity was obtained on the inclusion complex compared with the cyanazine. The results showed that the formation of inclusion complex could improve the application of cyanazine in agricultural production and reduce the risk to the environment.

Cyanazine/HPβCD inclusion complex was prepared to improve water solubility and thermal stability and herbicidal activity of cyanazine.

An antibacterial collagen membrane crosslinked by the inclusion complex of β-cyclodextrin dialdehyde and ofloxacin for bacterial keratitis

Infectious keratitis is one of the leading causes of blindness in the world, especially in developing countries. Corneal transplant surgery is a feasible treatment for bacterial keratitis when drug therapy cannot be effective. However, the amount of corneal donors is far from requirements of clinical treatment and thus, the prognosis of bacterial keratitis is not satisfactory. In this study, we developed a novel antibacterial corneal repair material (β-CD-DA/OFLX-Col) for bacterial keratitis. The inclusion complex of β-cyclodextrin dialdehyde (β-CD-DA) with ofloxacin formed by host–guest interaction was used as both a drug vector and a crosslinker for further reaction with the amino groups on lysine of collagen chains. Physical properties, cytocompatibility, and antibacterial property of β-CD-DA/OFLX-Col film were characterized. The results indicated that the film was mainly transparent and possessed superior mechanical properties. Moreover, human corneal epithelial cells could adhere to the film and proliferate normally, indicating that the β-CD-DA/OFLX-Col film was non-cytotoxic and had good biocompatibility. Most importantly, the β-CD-DA/OFLX-Col film exhibited prominent antibacterial effects against E. coli and S. aureus in vitro, which could minimize the risks of infection. The prepared β-CD-DA/OFLX-Col film could greatly increase bioavailability of drugs and reduce toxic side effects, thus displaying great potential in bacterial keratitis treatment.

The synthesis of antibacterial collagen membrane crosslinked by the inclusion complex of β-cyclodextrin dialdehyde and ofloxacin.

Encapsulation Mechanism of Oxyresveratrol by β-Cyclodextrin and Hydroxypropyl-β-Cyclodextrin and Computational Analysis

In this study, the encapsulation mechanism of oxyresveratrol and β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) was studied. As this research shows, oxyresveratrol and two cyclodextrins (CDs) were able to form inclusion complexes in a 1:1 stoichiometry. However, the interaction with HP-β-CD was more efficient, showing up as higher encapsulation constant (K_F) (35,864.72 ± 3415.89 M⁻¹). The K_F values exhibited a strong dependence on temperature and pH, which decreased as they increased. From the thermodynamic parameters (ΔH⁰, ΔS⁰, and ΔG⁰) of the oxyresveratrol loaded β-CD (oxyresveratrol-β-CD) and HP-β-CD (oxyresveratrol-HP-β-CD), it could be seen that the complexation process was spontaneous and exothermic, and the main driving forces between oxyrsveratrol and CDs were hydrogen bonding and van der waals force. Besides, molecular docking combined with ¹H-NMR were used to explain the most possible mode of interactions between oxyresveratrol and CDs.

Applications of nuclear magnetic resonance spectroscopy for the understanding of enantiomer separation mechanisms in capillary electrophoresis

This review deals with the applications of nuclear magnetic resonance (NMR) spectroscopy to understand the mechanisms of chiral separation in capillary electrophoresis (CE). It is accepted that changes observed in the separation process, including the reversal of enantiomer migration order (EMO), can be caused by subtle modifications in the molecular recognition mechanisms between enantiomer and chiral selector. These modifications may imply minor structural differences in those selector-selectand complexes that arise from the above mentioned interactions. Therefore, it is mandatory to understand the fine intermolecular interactions between analytes and chiral selectors. In other words, it is necessary to know in detail the structures of the complexes formed by the enantiomer (selectand) and the selector. Any differences in the structures of these complexes arising from either enantiomer should be detected, so that enantiomeric bias in the separation process could be explained. As to the nature of these interactions, those have been extensively reviewed, and it is not intended to be discussed here. These interactions contemplate ionic, ion-dipole and dipole-dipole interactions, hydrogen bonding, van der Waals forces, π-π stacking, steric and hydrophobic interactions. The main subject of this review is to describe how NMR spectroscopy helps to gain insight into the non-covalent intermolecular interactions between selector and selectand that lead to enantiomer separation by CE. Examples in which diastereomeric species are created by covalent (irreversible) derivatization will not be considered here. This review is structured upon the different structural classes of chiral selectors employed in CE, in which NMR spectroscopy has made substantial contributions to rationalize the observed enantioseparations. Cases in which other techniques complement NMR spectroscopic data are also mentioned.

Cyclodextrin and phospholipid complexation in solubility and dissolution enhancement: a critical and meta-analysis

INTRODUCTION

Poor solubility and dissolution of drugs are the major challenges in drug formulation and delivery. In order to improve the solubility and dissolution profile of drugs, various methods have been investigated so far. The cyclodextrin (CD) complexation and phospholipid (PL) complexation are among the exhaustively investigated methods employed for more precise improvement of the solubility and dissolution of poorly water-soluble drugs.

AREAS COVERED

The article discusses the CD and PL complexation techniques of solubility and dissolution enhancement. Various studies reporting the CD and PL complexation as the potential approaches to improve the dissolution, absorption and the bioavailability of the drugs have been discussed. The article critically reviews the physicochemical properties of CDs and PLs, eligibility of drugs for both the complexation, thermodynamics of complexation, methods of preparation, characterization, advantages, limitation and the meta-analysis of some studies for both the techniques.

EXPERT OPINION

The CD and PL complexation techniques are very useful in improving solubility and dissolution (and hence the bioavailability) of biopharmaceutical classification system Class II and Class IV drugs. The selection of a particular kind of complexation can be made on the basis of eligibility criteria (of drugs) for the individual techniques, cost, stability and effectiveness of the complexes.