Presence Of Cyclodextrins Research Articles

Diarylethene derivative photoionization control via two-color two-laser optical manipulation in the presence of cyclodextrins

In this study, the photodynamics of 1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)-3,3,4,4,5,5-hexafluoro-1-cyclopentene (DE) was investigated in the presence of α-, β- and γ-cyclodextrin (CD) inclusion complexes and under the influence of one- and two-laser excitations. Thus, this study aimed to elucidate the ionization quantum yield of DE and how it is affected by the type of CD and laser configuration. Specifically, DE/CD was flash photolyzed using a single laser (355 nm) or a double laser (355 nm and 532 nm) and observed at a wavelength of 720 nm to examine the transient absorption of hydrated electrons. The ionization efficiency with the two lasers was found to exceed that with the single laser. This suggests the existence of a two-step process involving S0→S1 and S1→Sn singlet transitions in the two-photon ionization (TPI) of DE. Furthermore, when the ring-closing isomer of DE was initiated via laser irradiation at 532 nm, the photoionization efficiency increased, especially in the presence of γ-CD. This implies that the 532-nm irradiation, which is not directly involved in TPI, contributed to promoting the TPI of DE, thus increasing its photo-steady state (saturation). Thus, the possibility of using CD-containing lasers to control photochemical reactions with photo-steady state processes was demonstrated. This investigation contributes to a broader understanding of the potential applications and underlying mechanisms of photochromic materials influenced by multi-laser interactions.

Supramolecular assemblies with macrocyclic hosts: applications in antibacterial activity

Abstract This review article focuses on the supramolecular assemblies fabricated through host-guest interaction using macrocycles such as cyclodextrins, calixarenes and cucurbiturils as hosts. Though several review articles have appeared on such host-guest assemblies having importance in controlled drug-delivery, fluorescence on-off sensors, catalysis etc., not much attention has been given to collect their potential applications in antibacterial activity. In this article we have mainly discussed the concepts, strategies and applications to enhance the antibacterial activity of different assemblies with some of the well-established antibacterial drugs/agents. The enhanced antibacterial activity of hydrogel, gelatin composite film, bismuth oxide nanoparticles and sanguinarine drug in the presence of cyclodextrins have been described in detail. The mechanism for the improved antibacterial activity of calixarene-capped nanoparticles, calixarene-complexed antibiotics and stimuli-responsive calixarene-based nanoassemblies for NO release was discussed. The enhanced photosensitizing effect of cucurbituril (CB) complexed porphyrins and their stimuli-responsive control over its antibacterial activity and the photothermal therapy has been elaborated. The effect of augmented antibacterial activity of CB-encapsulated drugs have also been given emphasis as they are promising for long-acting antibiotics.

Modulation of Distribution and Diffusion through the Lipophilic Membrane with Cyclodextrins Exemplified by a Model Pyridinecarboxamide Derivative.

The main aims of the study were to disclose the influence of the structure on the solubility, distribution and permeability of the parent substances, iproniazid (IPN), isoniazid (INZ) and isonicotinamide (iNCT), at 310.2 K and to evaluate how the presence of cyclodextrins (2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and methylated β-cyclodextrin (M-β-CD)) affects the distribution behavior and diffusion properties of a model pyridinecarboxamide derivative, iproniazid (IPN). The following order of decreasing the distribution and permeability coefficients was estimated: IPN > INZ > iNAM. A slight reduction of the distribution coefficients in the 1-octanol/buffer pH 7.4 and n-hexane/buffer pH 7.4 systems (more pronounced in the first system) was revealed. The extremely weak IPN/cyclodextrins complexes were estimated from the distribution experiments: KC(IPN/HP-β-CD) > KC(IPN/M-β-CD). The permeability coefficients of IPN through the lipophilic membrane-the PermeaPad barrier-were also measured with and without cyclodextrins in buffer solution. Permeability of iproniazid was increased in the presence of M-β-CD and reduced by HP-β-CD.

Linear relationship between emission quantum yield and Stokes shift in 3-styryl aza-coumarin based dyes in the presence of cyclodextrins

The effect of the cyclodextrins inclusion on the Stokes shifts and emission quantum yield of three 3-styryl aza-coumarin dyes (SACs) was experimentally and theoretically studied. Preliminary results show a relationship between the emission quantum yield and the calculated binding constants. Supramolecular inclusion was supported by changes in the fluorescence spectra, high-resolution mass spectrometry and molecular dynamics studies. 2,6-di-O-methyl-β-cyclodextrin (DM-β-CD) presented higher binding constants than β-cyclodextrin (β-CD), along with up to a 6-fold increase in emission quantum yield for the SACs. Additionally, a linear negative correlation was obtained between the Stokes shift and the emission quantum yield. This linear and empirical relationship was explained by the action of a unique intramolecular rotation and charge transfer phenomenon in the dyes, which was modulated by cyclodextrins, and supported by calculations based on density functional theory.

Interactions between Sodium Hyaluronate and β-Cyclodextrin as Seen by Transport Properties.

Knowledge of mass transport parameters, diffusion, and viscosity of hyaluronic acid (HA) in the presence of cyclodextrins is of considerable importance for areas such as food packaging and drug delivery, among others. Despite a number of studies investigating the functionalization of HA or the corresponding sodium salt by cyclodextrins, only a few studies have reported the effect of cyclodextrins on the mass transport of HA in the presence of these oligosaccharides. Here, we report the tracer binary and ternary interdiffusion coefficients of sodium hyaluronate (NaHy) in water and aqueous β-cyclodextrin solutions. The diffusion behavior of sodium hyaluronate was dependent on the reduced viscosity of NaHy, which, in turn, presented a concave dependence on concentration, with a minimum at approximately 2.5 g dm-3. The significant decrease in the limiting diffusion coefficient of NaHy (at most 45%) at NaHy concentrations below 1 g dm-3 in the presence of β-cyclodextrin, taking water as the reference, allowed us to conclude that NaHy strongly interacted with the cyclodextrin.

Determination of Terbinafine at a Boron-Doped Diamond (BDD) Electrode Modified with Polypyrrole and γ-Cyclodextrin by Square Wave Voltammetry (SWV)

This work involved the determination of the antifungal agent, terbinafine (TR) using a boron-doped diamond electrode (BDD) that was modified with polypyrrole in the presence of cyclodextrin. The obtained modified layer was overoxidized and was used to develop a novel, sensitive method for terbinafine. Scan rate measurements confirmed the diffusion character of the recorded currents. Terbinafine was irreversibly oxidized, producing a well-defined peak at +1.05 V (versus the saturated calomel electrode) in Britton–Robinson (B–R) buffer at pH 6.09. Square wave voltammetry was employed to study the relationship between current and terbinafine concentration in the optimized conditions. A linear range for terbinafine determination was obtained between 7.04 × 10−8 and 9.09 × 10−7 mol/L with a limit of detection of 2.11 × 10−8 mol/L and good repeatability (2.56%, n = 6 measurements, at 3.7 × 10−7 mol/L). The procedure was employed to determine terbinafine in pharmaceutical preparations. The recovery values between 97.37 and 102.16% demonstrate the accuracy of the developed protocol.

PdNP@Cyclodextrin on Cu/Al LDH-containing nanocomposites: Cage effect, crystallite size tuning and composite topology towards cross-couplings

A series of Cu/Al layered double hydroxides and Pd(0/II) composites containing native and modified cyclodextrins were prepared under different conditions of solvent (water or N,N-dimethylformamide), Pd precursors (Na2PdCl4 or Pd2dba3) and cyclodextrin/Pd ratios for the catalytic evaluation in Pd/Cu catalyzed cross-couplings aiming for the preparation of aryl thiophenes and N-arylamines. According to XPS measurements, the nanocomposites prepared in water presented a higher Pd(II)/Pd(0) ratio and subtle evidence of [PdCl4]2− intercalation by analyses of X-ray diffractograms. On the other hand, those prepared in N,N-dimethylformamide showed a higher content of Pd(0), probably dispersed on layered double hydroxides surface. SEM-FEG analyses combined with particle size distribution revealed that cyclodextrins were able to tune the size distribution, especially the β-form (15 nm in the presence of cyclodextrins). Powder X-rays diffraction data refinement using Rietveld method revealed that controlled palladium crystallite sizes of 11.53 nm and 10.22 nm were obtained in the presence of hydroxypropylated cyclodextrins (β and γ forms). Notably, the Rietveld refinement of the Pd nanocomposites revealed the presence of malachite, gibbsite, and sperniite phases in 23.05%, 23.05%, 15.23% contents. It suggests that Pd introduces a distortion in the initial LDH lattice. The catalytic activities of these nanocomposites were evaluated in Suzuki-Miyaura reaction in water/ethanol mixture, under low Pd loadings and room-temperature. Noteworthy, the nanocomposite prepared in N,N-dimethylformamide with native β-cyclodextrin showed higher catalytic activity (turnover number up to 7379) in Suzuki-Miyaura and Buchwald-Hartwig reactions for the synthesis of 2-aryl thiophenes, a component of several classes of functional organic electronic materials, and N-(4-nitrophenyl)-1,2-ethanediamine, respectively. This same nanocomposite was recycled up to three runs without loss in catalytic activity. A tentative test envisaging a one-pot borylation-Suzuki-Miyaura strategy indicated that the Miyaura borylation was conceivably affected by the coexisting malachite and spertiniite phases in the nanocomposite. However, control experiments in the presence of Cu(OH)2, Al(OH)3 and malachite indicate a lack of catalytic activity for these phases in Suzuki-Miyaura reactions. Thus, the catalytic activity is mostly attributed to the nanocomposite Cu–Al LDHs containing CDs. The enhancement in catalytic activity is suggested to occur as a result of deprotonation/adsorption of phenylboronic acid, transmetallation facilitated by a relatively high surface hydroxyl sites, improved substrate complexation by β-CDs and potential soluble Cu(II) active species from the layered matrix.

Fatigue Resistance of Photochromic Diarylethene in the Presence of Cyclodextrins with Different Pore Sizes

Abstract Among the various types of photochromic compounds, diarylethenes have good fatigue resistance, but further improvement is required. In this study, we investigated photochromic reaction behavior and fatigue resistance by inclusion in cyclodextrin (CD), which is a cyclic host molecule with three different pore sizes. A water-soluble diarylethene (DE1) synthesized in this work exhibited reversible photochromism in water. Continuous irradiation with UV light resulted in the formation of its byproduct. The addition of αCD showed no improvement of fatigue resistance. However, the addition of βCD and γCD suppressed a side reaction to result in the improvement of fatigue resistance. Especially, the addition of γCD gave a large improvement. To clarify the relationship between fatigue resistance of DE1 and the pore size of CD, the host-guest interaction between DE1 and CD was investigated using NOESY spectra. The results indicate that the depth of DE1 included in CD shows a large effect on suppression of the side reaction of DE1.

Improvement of the Hydrolytic Stability of the Keggin Molybdo- and Tungsto-Phosphate Anions by Cyclodextrins.

Keggin-type molybdo- and tungsto-phosphate polyoxoanions are among the most popular polyoxometalates (POMs) but suffer from their limited stability at low pH in aqueous solution. Their superchaotropic properties generate strong supramolecular complexes with cyclodextrins (CDs), which significantly affect the hydrolytic stability of POM. This chaotropically driven stabilization effect was systematically monitored by 31P NMR spectroscopy covering a wide range of pH (from 0 to 8) and varying the nature of the CD (α-, β-, and γ-form). A shift of ca. two pH units of the stability domains of these POMs was found in the presence of two equivalents of γ-CD compared to pure water, leading to keep intact the PW12O403- anion without any decomposition up to pH 3.5 (versus 1.5 in pure water) and pH 2.5 for PMo12O403-, which begins to decompose even at pH 0 in pure water. The effect of the smaller CDs (α- and β-form) is much less pronounced (only 0.5 pH units shift of the stability domain) confirming the importance of host-guest size matching to form a sandwich-type inclusion complex and thus protect the POM structure against basic hydrolysis. Such complexation was further supported by 183W and 1H NMR spectroscopy. Finally, using quantitative 31P NMR analyses, the new speciation and formation constants of phospho-molybdates and phospho-tungstates in the presence of cyclodextrins are determined and compared to those previously reported in pure water or in the 50:50 water/1,4-dioxane mixture.

Dissolution/Permeation of Albendazole in the Presence of Cyclodextrin and Bile Salts: A Mechanistic In Vitro Study into Factors Governing Oral Bioavailability

We aimed to understand the impact of the interplay between bile salts and cyclodextrins on the dissolution-permeation of poorly soluble drug compounds with a moderate-strong binding constant to cyclodextrin. Phase diagrams were prepared on the chosen model compound albendazole in phosphate buffer, fasted state simulated intestinal fluid (FaSSIF), and a modified fed state simulated intestinal fluid (FeSSIFmod) with (2-hydroxypropyl)-beta-cyclodextrin (HP-β-CD) concentrations of up to 10 % (m/m). Then we investigated the dissolution/permeation interplay of albendazole dissolved/suspended in the different media through a biomimetic barrier on a 96-well in vitro model. The apparent solubility of albendazole was enhanced by HP-β-CD and FaSSIF/FeSSIFmod separately. However, when albendazole was dissolved in HP-β-CD and biomimetic media together, the solubility was significantly lower than the predicted additive solubility from the solubilizing effects. It is postulated that this is due to the sodium taurocholate from the biomimetic media displacing albendazole from the hydrophobic cavity of HP-β-CD. In the permeation experiments, the highest permeation was observed at cyclodextrin concentrations able to solubilize close to the total dose of albendazole without a major surplus of solubilization capacity. Furthermore, an over-proportional permeation enhancement was observed when both, cyclodextrin and biomimetic media were present. These results indicate that the interplay between bile salts and cyclodextrins can enhance the free (molecularly dissolved) fraction of drug in solution to a greater extent than could be obtained with one of the solubilizing components alone. In conclusion, at carefully selected cyclodextrin-concentrations in combination with biomimetic media, obviously, a transient supersaturation is induced, which is made responsible for the observed major permeation enhancement.

Effect of cyclodextrins’ cavity on the kinetics of alkaline hydrolysis of tris(1,10-Phenanthroline)Fe(II) in presence of surfactant

The kinetics of alkaline hydrolysis of tris(1,10-phenanthroline)Fe(II) has been explored spectrophotometrically in the presence of cyclodextrins (CDs), quaternary amphiphile (CTAB), and their mixed systems. All kinetics run in pseudo-first order conditions with excess concentration of alkali at 298 K (± 0.1 K). The reaction rate accelerates in the presence of CTAB. However, in the presence of CDs, the observed rate constant decreases continuously and also the catalytic properties of amphiphile diminishes, indicating the inclusion of both tris(1,10-phenanthroline)Fe(II) and surfactant into the CD cavity in the hydrolysis reaction. The cavity size of γ-CD among all of the CDs favors the incorporation of both Fe(II) complex and CTAB, which significantly reduces the micellar surface catalysis of CTAB. The decreasing sequence of the rate in CTAB-CDs mixed systems is observed as γ-CD > β-CD > α-CD. All the experimental kinetic results have been well explained based on the pseudo-phase model (PP model) of micelles and CD-inhibited model of CD systems. The calculated theoretical rate constant values are well consistent with the experimental data. In the absence and presence of CTAB, the calculated values of equilibrium binding constant between Fe(phen)3 2+ and γ-CD () are 109.17 (±1.03) and 414.74 (±3.63) (L mol−1), respectively, which support the diminishing of the catalytic properties of CTAB in the presence of γ-CD in the hydrolysis reaction. The experimental results also corroborate that fact. Finally, the effect of temperature on the reaction rate has been observed and the thermodynamic activation parameters have been evaluated. The linear plot of standard activated enthalpy with standard activated entropy reveals an iso-kinetic relationship that confirms a common mechanism for the reaction in different environments.

Liposomes as nonspecific nanocarriers for 5-Fluorouracil in the presence of cyclodextrins

5-Fluorouracil (5-FU) is one of anticancer drugs with broad activity. Due to its severe side effects, recent studies concentrate on new ways of directed 5-FU delivery and its release in ill tissue. One of selective carriers could be cyclodextrins and liposomes. The combination of novel methods, leading to formation of inclusion complexes (IC) between host molecule of β-cyclodextrin (β-CD) or 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and 5-FU guest and its subsequent encapsulation in dipalmitoylphosphatidylcholine (DPPC) liposomes is studied experimentally in the present work. Several methods are applied to proof the encapsulation of the analysed drug and its release over time at 37 and 41 °C. The 5-FU release from complex of liposomal form of 5-fluorouracil and β-cyclodextrin (L[DPPC/5-FU]:β-CD) and complex of liposomal form of 5-fluorouracil and (2-hydroxypropyl)-β-cyclodextrin (L[DPPC/5-FU]:HP-β-CD) was followed using UV–Vis and fluorescence spectroscopy, proton nuclear magnetic resonance (1H NMR) and differential scanning calorimetry (DSC) techniques. The electronic and NMR spectra analysis were additionally supported by molecular modeling, including prediction of spectral changes in vacuum and in water using density functional theory (DFT-B3LYP-D3). From the observed changes the fastest release from liposomes (within 1 h) was observed for the 5-FU complexes with HP-β-cyclodextrin at 41 °C.

Deciphering Spectroscopic and Structural Insights into the Photophysical Behavior of 2,2'-Dipyridylamine: An Efficient Environment Sensitive Fluorescence Probe.

Excited state deactivation properties and the effects of solvent hydrogen bonding (HB) on the photophysical behavior of 2,2'-dypyridylamine (DPyA) were investigated by steady state and time-resolved fluorescence experiments, molecular docking, and density functional theory (DFT) calculations. In addition to the polarity effect, the contributions of solvent HB donation (HBD) acidity and HB acceptance (HBA) basicity to modulate the solvatochromic spectral properties were estimated from multiparametric linear regression analysis using Kamlet-Taft (KT) and Catalán formalisms. The importance of C-N bond torsion, leading to the trans → cis conversion, was manifested by substantial increase in DPyA fluorescence yield in the presence of cyclodextrin (CD) and glycerol. The unusually low fluorescence yield in aqueous medium was explained on the basis of synergistic effect of solvent hydrogen bonding combined with excited state conformational isomerization, which renders DPyA to be an excellent environment sensitive fluorescence reporter. The experimental results were verified with structural insights obtained from DFT calculations at B3LYP/6-311++G(d,p) level and construction of potential energy surface (PES) in the ground state as well as in the excited states.

A Newly Designed Water Soluble Uranyl-Salophen Complex for Anion Recognition.

A novel water‐soluble uranyl‐salophen (salophen=N,N‘‐disalicylidene‐o‐phenylenediaminate) complex was obtained. Solubility was achieved in aqueous methyl‐β‐cyclodextrin solutions, taking advantage of the host‐guest interactions established with the adamantyl moieties present on the ligand skeleton. Such an approach facilitates the synthesis of the receptor and the purification processes and, in perspective, can be definitely applicable to other molecular scaffolds. UV/Vis titration experiments demonstrate that the capacity of the uranyl‐salophen core to behave as a receptor for anions is retained in water and appears comparable with that previously reported for other water‐soluble uranyl‐salophen systems. Hence the presence of cyclodextrins does not interfere with molecular recognition processes.

UV SPECTROSCOPY AND KINETIC RESEARCH OF PHOTODEGRADATION OF METHYL ORANGE IN THE PRESENCE OF TITANIUM DIOXIDE AND β-CYCLODEXTRIN OR ITS DERIVATIVES

The research is devoted to the study of the effect of β-cyclodextrin (β-CD) and its derivatives on the photocatalytic degradation of methyl orange in aqueous solutions in the presence of titanium dioxide. It has been shown that the kinetics of photodegradation of methyl orange is more accurately described by the pseudo first order equation for all investigated pH values. In the presence of cyclodextrins β-CD and 2-hydroxypropyl-β-cyclodextrin, acceleration of photodegradation was observed only after 30 min of irradiation. As a result, the oxidation of hydroxyl groups of cyclodextrin occurred. A significant slowdown in photodestruction in the TiO2-β-CD sample during the first 45 min is explained by the formation of inclusion complexes of cyclodextrin with methyl orange, which prevented the destruction of dye. The use of the β-cyclodextrin, its derivatives and increasing the acidity of the medium accelerates the processes of photodestruction of methyl orange in distilled and natural waters. Methyl orange was decolorized for 20 – 25 min in solutions of all investigated cyclodextrin derivatives at pH 2.5. The destruction of methyl orange was most effective with the use of sulfobutyl ether β-CD. The bactericidal lamp (λ = 254 nm) allows to increase the rate of destruction during the irradiation process. Methyl orange discolored much faster under the action of a bactericidal lamp than using only ultraviolet lamps with λ = 365 nm. A slight slowdown in the decomposition process is observed after several irradiation cycles. This may be due to the influence of the formed products of destruction. However, under such conditions, the by-products of reactions decompose much faster. The use of cyclodextrins is possible without significant loss of efficiency up to 8 cycles.

In Ukrainian

The encapsulation of medicinal substances in various polymers is a common way to increase their thermal, hydrolytic, and chemical stability. However, the bioavailability of the encapsulated drugs decreases. The solution to this important problem can be the preparation of nanocapsules of medicinal substances using complexing agents, for example, cyclodextrins. The purpose of this work is to study the possibility of encapsulation of benzoic, salicylic, and β-resorcylic acids using α- and β-cyclodextrins. The interaction of benzene carboxylic acids with cyclodextrins in aqueous solutions at 20–30 оС has been studied by spectrophotometry. The formation of complexes with a composition of 1:1 in the cyclodextrin – benzene carboxylic acid systems has been proven. The stability constants of the complexes and the main thermodynamic parameters of complex formation have been calculated. It has been shown that the nature of changes in the spectral characteristics of benzene carboxylic acids in the presence of cyclodextrins can be used to predict the possibility of aromatic organic compounds encapsulation. The determining role of the complementarity of geometric parameters of cyclodextrins and benzene carboxylic acids in the preparation of inclusion complexes with features of nanocapsules has been found. The prospects of using β-cyclodextrin for encapsulation of benzene carboxylic acids have been demonstrated. The complexes of β-cyclodextrin with benzene carboxylic acids were synthesized and studied by IR spectroscopy, X-ray analysis and derivatography. The formation of two types of complexes in the β-cyclodextrin – benzene carboxylic acid system was established. The first type of complexes is formed due to nonspecific interactions between the hydrophobic cavity of β-cyclodextrin and the benzene carboxylic acid molecule, the second type is due to specific interactions between the functional groups of molecules. Benzoic and salicylic acids form nanocapsules with β-cyclodextrin, and their hydrolytic and thermal stability increases. Complexes of the second type acquire the properties of a new compound: β-resorcylic acid loses its individuality, forming strong supramolecular structures with β-cyclodextrin.

Direct short-wave photolysis of chlorpyrifos-methyl and chlorpyrifos-methyl oxon in the presence of cyclodextrins

Direct short-wave photolysis of chlorpyrifos-methyl (1) and chlorpyrifos-methyl oxon (2) was studied in the presence of native cyclodextrins (α–, β– and γ–CD) and randomly methylated β–CD (RAMEB). We used for irradiation low pressure Hg lamps emitting at 254 nm and used as solvent 10% acetonitrile (ACN)/H2O solutions. The formation of an inclusion complex between 1 and β–CD was evaluated by UV–vis and NMR techniques. We did observe on UV–vis an interaction with β–CD, a feeble one not enough to enable the determination of the association constants. The experiments allowed us to assess that the presence of cyclodextrins produce a more rapid consumption of 1 and 2 compared to the naked molecules. A much faster photodegradation for the two compounds was observed in the presence of γ–CD. The average, at two wavelengths, of calculated ratios for the enhanced photodegradation of 1 were 1.3, 2.9, 25.8 and 2.9 for α–, β–, γ–CD and RAMEB, while in the case of 2, they reached 1.4, 3.5, 8.5 and 4.1 respectively. Our results indicate that short-wave photolysis of 1 in the presence of cyclodextrins could become a better plausible detoxification mechanism compared with their absence.

Tedizolid-Cyclodextrin System as Delayed-Release Drug Delivery with Antibacterial Activity.

Progressive increase in bacterial resistance has caused an urgent need to introduce new antibiotics, one of them being oxazolidinones with their representative tedizolid. Despite the broad spectrum of activity of the parent tedizolid, it is characterized by low water solubility, which limits its use. The combination of the active molecule with a multifunctional excipient, which is cyclodextrins, allows preservation of its pharmacological activity and modification of its physicochemical properties. Therefore, the aim of the study was to change the dissolution rate and permeability through the model membrane of tedizolid by formation of solid dispersions with a cyclodextrin. The research included identification of tedizolid-hydroxypropyl-β-cyclodextrin (tedizolid/HP-β-CD) inclusion complex by thermal method (Differential Scanning Colorimetry), spectroscopic methods (powder X-ray diffraction, Fourier-Transform Infrared spectroscopy), and molecular docking. The second part of the research concerned the physicochemical properties (dissolution and permeability) and the biological properties of the system in terms of its microbiological activity. An increase in the dissolution rate was observed in the presence of cyclodextrin, while maintaining a high permeation coefficient and high microbiological activity. The proposed approach is an opportunity to develop drug delivery systems used in the treatment of resistant bacterial infections, in which, in addition to modifying the physicochemical properties caused by cyclodextrin, we observe a favorable change in the pharmacological potential of the bioactives.

Lifespan extension in Caenorhabditis elegans by oxyresveratrol supplementation in hyper-branched cyclodextrin-based nanosponges.

In this work, the increase of the Caenorhabditis elegans (C. elegans) lifespan extension using hyper-branched cyclodextrin-based nanosponges (CD-NS) complexing oxyresveratrol (OXY), and the possible inhibition of C. elegans phosphodiesterase type 4 (PDE4) were evaluated. The titration displacement of fluorescein was used to calculate the apparent complexation constant (KF) between CD-NS and OXY. Moreover, PDE4 was expressed in E. coli, purified and refolded in presence of cyclodextrins (CDs) to study its possible inhibition as pharmacological target of OXY. The apparent activity was characterized and the inhibitory effect of OXY on PDE4 displayed a competitive in vitro inhibition corroborated in silico. A maximum increase of the in vivo life expectancy of about 9.6% of using OXY/CD-NS complexes in comparison with the control was obtained, in contrast to the 6.5% obtained with free OXY. No effect on lifespan or toxicity with CD-NS alone was found. These results as a whole represent new opportunities to use OXY and CD-NS in lifespan products.

Budesonide-Cyclodextrin in Hydrogel System: Impact of Quaternary Surfactant on in vitro-in vivo Assessment of Mucosal Drug Delivery

Budesonide, a glucocorticosteroid is generally used to treat chronic inflammation and asthma. Hepatic first-pass metabolism and poor solubility are the major causes of its limited oral bioavailability. Present work was undertaken for the preparation of hydrogel film formulation with cyclodextrin complexation of budesonide containing quaternary surfactant for possible enhancement of mucosal permeation. FTIR study confirmed drug-polymer hydrogen bonding. Almost complete amorphization of the drug was pronounced by SEM, DSC and XRD studies. The film containing benzalkonium and hydroxypropyl beta-cyclodextrin exhibited in vitro dissolution and mucosal permeation to the highest extent of 87.2 and 95.8 % respectively in contrast to the others. Film formed hydrogel in aqueous mucin and enhanced the mucosal tissue residence time due to the mucoadhesive nature of the polymer. Acute inflammation in the rabbit eye was controlled within 3 h by applying the film in the cul-de-sac. The presence of cyclodextrin and quaternary surfactant brought about significantly improved drug release and mucosal permeation compared to their absence in the HPMC film. Hydrogel formed in aqueous mucin enhanced the mucosal residence time and controlled acute inflammation in the rabbit eye within 3 h after topical application.