Equilibrium, structural and antibacterial characterization of moxifloxacin-β-cyclodextrin complex

New Weapons to Fight against Staphylococcus aureus Skin Infections

The treatment of Staphylococcus aureus skin and soft tissue infections faces several challenges, such as the increased incidence of antibiotic-resistant strains and the fact that the antibiotics available to treat methicillin-resistant S. aureus present low bioavailability, are not easily metabolized, and cause severe secondary effects. Moreover, besides the susceptibility pattern of the S. aureus isolates detected in vitro, during patient treatment, the antibiotics may never encounter the bacteria because S. aureus hides within biofilms or inside eukaryotic cells. In addition, vascular compromise as well as other comorbidities of the patient may impede proper arrival to the skin when the antibiotic is given parenterally. In this manuscript, we revise some of the more promising strategies to improve antibiotic sensitivity, bioavailability, and delivery, including the combination of antibiotics with bactericidal nanomaterials, chemical inhibitors, antisense oligonucleotides, and lytic enzymes, among others. In addition, alternative non-antibiotic-based experimental therapies, including the delivery of antimicrobial peptides, bioactive glass nanoparticles or nanocrystalline cellulose, phototherapies, and hyperthermia, are also reviewed.

Mucosal Adhesive Chitosan Nanogel Formulations of Antibiotics and Adjuvants (Terpenoids, Flavonoids, etc.) and Their Potential for the Treatment of Infectious Diseases of the Gastrointestinal Tract

Bacterial infections are usually found in the stomach and the first part of the small intestine in association with various pathologies, including ulcers, inflammatory diseases, and sometimes cancer. Treatment options may include combinations of antibiotics with proton pump inhibitors and anti-inflammatory drugs. However, all of them have high systemic exposure and, hence, unfavorable side effects, whereas their exposure in stomach mucus, the predominant location of the bacteria, is limited. Chitosan and nanogels based on chitosan presumably are not absorbed from the gastrointestinal tract and are known to adhere to the mucus. Therefore, they can serve as a basis for the local delivery of antibacterial drugs, increasing their exposure at the predominant location of therapeutic targets, thus improving the risk/benefit ratio. We have used E. coli ATCC 25922 (as a screening model of pathogenic bacteria) and Lactobacilli (as a model of a normal microbiome) to study the antibacterial activity of antibacterial drugs entrapped in a chitosan nanogel. Classical antibiotics were studied in a monotherapeutic regimen as well as in combination with individual terpenoids and flavonoids as adjuvants. It has been shown that levofloxacin (LF) in combination with zephirol demonstrate synergistic effects against E. coli (cell viability decreased by about 50%) and, surprisingly, a much weaker effect against Lactobacilli. A number of other combinations of antibiotic + adjuvant were also shown to be effective. Using FTIR and UV spectroscopy, it has been confirmed that chitosan nanogels with the drug are well adsorbed on the mucosal model, providing prolonged release at the target location. Using an ABTS assay, the antioxidant properties of flavonoids and other drugs are shown, which are potentially necessary to minimize the harmful effects of toxins and radicals produced by pathogens. In vivo experiments (on sturgeon fish) showed the effective action of antibacterial formulations developed based on LF in chitosan nanogels for up to 11 days. Thus, chitosan nanogels loaded with a combination of drugs and adjuvants can be considered as a new strategy for the treatment of infectious diseases of the gastrointestinal tract.

Mannosylated Systems for Targeted Delivery of Antibacterial Drugs to Activated Macrophages

Macrophages are a promising target for drug delivery to influence macrophage-associated processes in the body, namely due to the presence of resistant microorganisms in macrophages. In this work, a series of mannosylated carriers based on mannan, polyethylenimine (PEI) and cyclodextrin (CD) was synthesized. The molecular architecture was studied using FTIR and ¹H NMR spectroscopy. The particle size, from small 10-50 nm to large 500 nm, depending on the type of carrier, is potentially applicable for the creation of various medicinal forms: intravenous, oral and inhalation. Non-specific capture by cells with a simultaneous increase in selectivity to CD206+ macrophages was achieved. ConA was used as a model mannose receptor, binding galactosylated (CD206 non-specific) carriers with constants of the order of 10⁴ M^-1 and mannosylated conjugates of 10⁶-10⁷ M^-1. The results of such primary "ConA-screening" of ligands are in a good agreement in terms of the comparative effectiveness of the interaction of ligands with the CD206+ macrophages: non-specific (up to 10%) absorption of highly charged and small particles; weakly specific uptake of galactosylated polymers (up to 50%); and high affine capture (more than 70-80%) of the ligands with grafted trimannoside was demonstrated using the cytometry method. Double and multi-complexes of antibacterials (moxifloxacin with its adjuvants from the class of terpenoids) were proposed as enhanced forms against resistant pathogens. In vivo pharmacokinetic experiments have shown that polymeric carriers significantly improve the efficiency of the antibiotic: the half-life of moxifloxacin is increased by 2-3 times in conjugate-loaded forms, bio-distribution to the lungs in the first hours after administration of the drug is noticeably greater, and, after 4 h of observation, free moxifloxacin was practically removed from the lungs of rats. Although, in polymer systems, its content is significant-1.2 µg/g. Moreover, the importance of the covalent crosslinking carrier with mannose label was demonstrated. Thus, this paper describes experimental, scientifically based methods of targeted drug delivery to macrophages to create enhanced medicinal forms.

Mannosylated Polymeric Ligands for Targeted Delivery of Antibacterials and Their Adjuvants to Macrophages for the Enhancement of the Drug Efficiency

Bacterial infections and especially resistant strains of pathogens localized in macrophages and granulomas are intractable diseases that pose a threat to millions of people. In this paper, the theoretical and experimental foundations for solving this problem are proposed due to two key aspects. The first is the use of a three-component polymer system for delivering fluoroquinolones to macrophages due to high-affinity interaction with mannose receptors (CD206). Cytometry assay determined that 95.5% macrophage-like cells were FITC-positive after adding high-affine to CD206 trimannoside conjugate HPCD-PEI1.8-triMan, and 61.7% were FITC-positive after adding medium-affine ligand with linear mannose label HPCD-PEI1.8-Man. The second aspect is the use of adjuvants, which are synergists for antibiotics. Using FTIR and NMR spectroscopy, it was shown that molecular containers, namely mannosylated polyethyleneimines (PEIs) and cyclodextrins (CDs), load moxifloxacin (MF) with dissociation constants of the order of 10⁻⁴–10⁻⁶ M; moreover, due to prolonged release and adsorption on the cell membrane, they enhance the effect of MF. Using CLSM, it was shown that eugenol (EG) increases the penetration of doxorubicin (Dox) into cells by an order of magnitude due to the creation of defects in the bacterial wall and the inhibition of efflux proteins. Fluorescence spectroscopy showed that 0.5% EG penetrates into bacteria and inhibits efflux proteins, which makes it possible to increase the maximum concentration of the antibiotic by 60% and maintain it for several hours until the pathogens are completely neutralized. Regulation of efflux is a possible way to overcome multiple drug resistance of both pathogens and cancer cells.

Enhanced antibacterial activity of levofloxacin/hydroxypropyl-β-cyclodextrin inclusion complex: In vitro and in vivo evaluation

Levofloxacin is the levo-enantiomer of ofloxacin (a fluoroquinolone class of antibacterial drug). Cyclodextrins (CDs) including hydroxypropyl-β-cyclodextrin (HPβCD) are generally used as a chiral selector for the enantioseparation of some drugs including levofloxacin or as a drug/food nanocarrier for the efficacy improvement of many pharmaceuticals. We hypothesized that the cyclodextrin inclusion is potentially able to further improve the antibacterial activity of levofloxacin. To test this hypothesis, the levofloxacin/HPβCD inclusion complex was prepared by the freeze-drying method and characterized by phase solubility diagram, differential scanning calorimetry (DSC), X-ray diffractometry (XRD), UV-Vis spectrophotometer, and ¹H NMR spectroscopy, confirming the successful HPβCD inclusion of levofloxacin. The in vitro antibacterial effects of HPβCD, levofloxacin, and the levofloxacin/HPβCD inclusion complex against four different bacterial strains in liquid media and on agar plates were determined/compared (an MIC₉₀ of 0.5-1.0 μg/mL for the inclusion complex compared with that of 1.0-2.0 μg/mL for free levofloxacin in liquid). Moreover, the in vivo antibacterial effects of levofloxacin and levofloxacin/HPβCD inclusion complex were tested by using a skin scald model in mice infected with Staphylococcus aureus, and decreased amounts of both bacteria and leukocytes were detected in scalded skin after the inclusion complex treatment. The data revealed that the levofloxacin/HPβCD inclusion complex had an enhanced antibacterial activity compared with free levofloxacin. It implies that cyclodextrins (e.g. HPβCD) may have a beneficial role when using as a chiral selector or as a drug nanocarrier for levofloxacin and that the levofloxacin/HPβCD inclusion complex has the potential of being developed into a pharmaceutical for antibacterial therapies.

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.

Spectroscopy Approach for Highly-Efficient Screening of Lectin-Ligand Interactions in Application for Mannose Receptor and Molecular Containers for Antibacterial Drugs

Rational search of a ligand for a specific receptor is a cornerstone of a typical drug discovery process. However, to make it more “rational” one would appreciate having detailed information on the functional groups involved in ligand-receptor interaction. Typically, the 3D structure of a ligand-receptor complex can be built on the basis of time-consuming X-ray crystallography data. Here, a combination of FTIR and fluorescence methods, together with appropriate processing, yields valuable information about the functional groups of both the ligand and receptor involved in the interaction, with the simplicity of conventional spectrophotometry. We have synthesized the “molecular containers” based on cyclodextrins, polyethyleneimines (PEI) or spermine with mannose-rich side-chains of different molecular architecture (reticulated, star-shaped and branched) with variable parameters to facilitate delivery to alveolar macrophages. We have shown that synthetic mannose-rich conjugates are highly affine to the model mannose receptor ConA: K_d ≈ 10⁻⁵–10⁻⁷ M vs. natural ligand trimannoside (10⁻⁵ M). Further, it was shown that molecular containers effectively load levofloxacin (dissociation constants are 5·10⁻⁴–5·10⁻⁶ M) and the eugenol adjuvant (up to 15–80 drug molecules for each conjugate molecule) by including them in the cyclodextrins cavities, as well as by interacting with polymer chains. Promising formulations of levofloxacin and its enhancer (eugenol) in star-shaped and polymer conjugates of high capacity were obtained. UV spectroscopy demonstrated a doubling of the release time of levofloxacin into the external solution from the complexes with conjugates, and the effective action time (time of 80% release) was increased from 0.5 to 20–70 h. The synergy effect of antibacterial activity of levofloxacin and its adjuvants eugenol and apiol on Escherichia coli was demonstrated: the minimum effective concentration of the antibiotic was approximately halved.

Investigation of the effects of three different generations of fluoroquinolone derivatives on antioxidant and immunotoxic enzyme levels in different rat tissues

Fluoroquinolones (FQs) are synthetic and broad-spectrum antimicrobial drugs derived from nalidixic acid. FQs are used against SARS-CoV-2 in our country, and for the treatment of some urinary tract diseases, gastrointestinal diseases, respiratory tract diseases, sexually transmitted diseases, and dermatological diseases. The present study investigated the effect of 1-,7-,14-day treatments of three different FQ derivatives; ciprofloxacin (CIP) 80 mg/kg/day, levofloxacin (LVX) 40 mg/kg/day, and moxifloxacin (MXF) 40 mg/kg/day, on biochemical parameters, lipid peroxidation, antioxidant enzymes, and immunotoxicity. 72 Wistar albino male rats were distributed to four groups including 18 rats in each group and were sacrificed on three different time points. The 14-day treatment of MXF significantly reduced the levels of aspartate aminotransferase (AST), glucose, reduced glutathione (GSH), malondialdehyde (MDA), catalase (CAT), myeloperoxidase (MPO), adenosine deaminase (ADA), and glutathione peroxidase (GPx). Furthermore, 14-day treatment of LVX increased liver [GSH, MPO, ADA, superoxide dismutase (SOD)], and GSH (erythrocyte) levels; whereas it significantly reduced the levels of AST, TG (triglycerides) and associated parameters levels in all the tissues (MDA), erythrocytes, and liver (MPO, CAT, SOD, GPx). After 14-day treatment of CIP; the erythrocyte levels of GSH, MPO, GPx, and CAT significantly decreased; whereas the levels of glucose, creatinine, MPO (liver), and GST (kidney and erythrocyte) significantly increased. It has been concluded that FQ derivatives used in this experiment did not display any correlation in terms of the efficacies in the different time points and tissues. Thus, it is recommended to use such FQ derivatives considering the duration of use and target tissue.

Moxifloxacin and Sulfamethoxazole-Based Nanocarriers Exhibit Potent Antibacterial Activities

Antibiotic resistance is a major concern given the rapid emergence of multiple-drug-resistant bacteria compared to the discovery of novel antibacterials. An alternative strategy is enhancing the existing available drugs. Nanomedicine has emerged as an exciting area of research, showing promise in the enhanced development of existing antimicrobials. Herein, we synthesized nanocarriers and loaded these with available clinically approved drugs, namely Moxifloxacin and Sulfamethoxazole. Bactericidal activity against Gram-negative (Serratia marcescens, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Salmonella enterica) and Gram-positive (methicillin-resistant Staphylococcus aureus, Streptococcus pneumoniae, and Bacillus cereus) bacteria was investigated. To characterize the nanocarriers and their drug-loaded forms, Fourier-transform infrared spectroscopy, dynamic light scattering, and atomic force microscopy were utilized. Antibacterial assays and hemolysis assays were carried out. Moreover, lactate dehydrogenase assays were performed to determine cytotoxicity against human cells. The results depicted the successful formation of drug-nanocarrier complexes. The potent antibacterial activities of the drug-loaded nanocarriers were observed and were significantly enhanced in comparison to the drugs alone. Hemolysis and cytotoxicity assays revealed minimal or negligible cytotoxic effects against human red blood cells and human cells. Overall, metronidazole-based nanocarriers loaded with Moxifloxacin and Sulfamethoxazole showed enhanced bactericidal effects against multiple-drug-resistant bacteria compared with drugs alone, without affecting human cells. Our findings show that drug-loaded nanocarriers hold promise as potent chemotherapeutic drugs against multiple-drug-resistant bacteria.

Moxifloxacin loaded nanoparticles of disulfide bridged thiolated chitosan-eudragit RS100 for controlled drug delivery

The aim of our study was to prepare nanoparticles of disulfide bridged thiolated chitosan and eudragit RS100 using the air oxidation method for controlled drug delivery. The developed nanoparticles were characterized by FTIR, DSC, TGA, zeta sizer, zeta potential, SEM and ¹H NMR. The loading, entrapment efficiency and in-vitro release of moxifloxacin from nanoparticles was determined. Toxicity was studied using Caco-2 cell line and pharmacokinetics of moxifloxacin from the developed nanoparticles was studied in albino rats. The FTIR analysis showed no chemical interaction of the drug with the thiolated polymers. The DSC and TGA showed the thermal stability of nanoparticles. The average particle size of nanoparticles was 87 nm, zeta potential of NTC3 was ± 19 and SEM showed the spherical shape of nanoparticles. The ¹H NMR spectra confirmed the structure of thiolated chitosan and eudragit RS100. The loading, encapsulation efficiency and release of moxifloxacin from NTC3 were 100.3%, 89.67% and 88.49% respectively. The nanoparticles in culture medium did not affect the viability of Caco-2 cells. The NTC3 formulation showed a greater bioavailability of moxifloxacin compared to the reference formulation. The study reports a convenient and effective way to prepare a chitosan and eudragit RS100 based drug delivery system with a controlled release pattern.

Thermochromic Hydrogel-Functionalized Textiles for Synchronous Visual Monitoring of On-Demand In Vitro Drug Release

In vitro drug release systems have recently received tremendous attention because they allow noninvasive, convenient, and prolonged administration of pharmacological agents. On-demand epidermal drug release systems can improve treatment efficiency, prevent multidrug resistance, and minimize drug toxicity to healthy cells. In addition, real-time monitoring of drug content is also essential for guiding the determination of drug dosage and replacing drug carriers in time. Therefore, it is important to integrate the above properties in one ideal epidermal patch. Herein, photonic crystals (PCs) based on Fe₃O₄@C nanoparticles were introduced into drug-loaded poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAM-AAc)) hydrogel-functionalized textiles. Drug loading and release depended on the expansion and contraction of the hydrogels. The lower critical solution temperature (LCST) of the hydrogels was adjusted to 40 °C, which is higher than the skin temperature, by varying the content of hydrophilic comonomer acrylic acid (AAc) to store the drug at room temperature, and on-demand release was achieved by mild thermal stimulation. Moreover, the lattice spacing (d) of PCs varied with the expansion and contraction of the hydrogels, which can cause the color of P(NIPAM-AAc) hydrogel-functionalized textiles to change. These synchronous thermoresponsive chromic drug uptake and release behaviors provided an effective method for visual and real-time monitoring of drug content. Furthermore, in view of the poor mechanical properties of hydrogel wound dressings, textile matrices were composited to prevent holistic breaking during the stretching process. Biological experiments proved that the drug-loaded P(NIPAM-AAc) hydrogel-functionalized textiles had good antibacterial properties and wound-healing effects.

Characterization and effect of nanocomplexed fluoride solutions on the inhibition of enamel demineralization created by a multispecies cariogenic biofilm model

OBJECTIVES

The aim of this study was to assess the in vitro caries preventive effect of nanocomplexed solutions of hydroxypropyl-β-cyclodextrin and γ-cyclodextrin associated with titanium tetrafluoride (TiF₄) after different complexation times (12 or 72 h).

MATERIALS AND METHODS

Enamel blocks were randomly distributed in 9 groups (n = 11): negative control, hydroxypropyl-β-cyclodextrin, γ-cyclodextrin, TiF₄, hydroxypropyl-β-cyclodextrin:TiF₄ 12 h, hydroxypropyl-β-cyclodextrin:TiF₄ 72 h, γ-cyclodextrin:TiF₄ 12 h, γ-cyclodextrin:TiF₄ 72 h, and NaF (positive control). The solutions were applied for 1 min and the blocks were exposed to a biofilm model. Nanocompounds were characterized by differential scanning calorimetry and X-ray powder diffraction. The percentage of surface microhardness loss (%SML), mineral density changes (ΔZ), lesion depth, surface morphology (scanning electron microscopy-SEM), and chemical characterization (energy-dispersive spectroscopy-EDS) were assessed.

RESULTS

No oxidation was observed, and the formation of the nanocomplexes was evidenced by changes in the melting point compared to pure cyclodextrins and the loss of crystallinity of the materials. Hydroxypropyl-β-cyclodextrin:TiF₄ 72 h resulted in lower %SML than negative control, hydroxypropyl-β-cyclodextrin, γ-cyclodextrin, and TiF₄ (p < 0.05). NaF differed from all groups (p < 0.05), except for hydroxypropyl-β-cyclodextrin:TiF₄ 72 h (p = 0.83). ΔZ of hydroxypropyl-β-cyclodextrin:TiF₄ 72 h was higher than negative control, hydroxypropyl-β-cyclodextrin, γ-cyclodextrin, γ-cyclodextrin:TiF₄ 1 2 h, γ-cyclodextrin:TiF₄ 72 h, and NaF (p < 0.05) and similar to TiF₄ and hydroxypropyl-β-cyclodextrin:TiF₄ 12 h (p > 0.05). SEM/EDS detected Ti in the blocks subjected to TiF₄-products.

CONCLUSION

The hydroxypropyl-β-cyclodextrin:TiF₄ 72 h solution showed caries preventive effect on the surface and subsurface of the enamel.

CLINICAL RELEVANCE

A hydroxypropyl-β-cyclodextrin nanosystem, in association with TiF₄ after 72 h of complexation, may be a promising agent for the prevention of enamel demineralization.

Development and physicochemical characterization of chitosan hydrochloride/sulfobutyl ether-β-cyclodextrin nanoparticles for cinnamaldehyde entrapment

In this work, the cinnamaldehyde (CA) loaded nanoparticles were synthesized by directly cross-linking chitosan hydrochloride (CSH) and sulfobutyl ether-β-cyclodextrin (SBE-β-CD). The CA/SBE-β-CD inclusion complex was firstly prepared, and its highest encapsulation efficiency (EE) was 86.34%. Field Emission Scanning Electron Microscope results indicated that the inclusion complex showed massive aggregates with a coarse and fluffy texture and irregular surface. Then, the inclusion complex interacted with CSH to form nanoparticles. The EE of CA in nanoparticles was improved. Atomic force microscopy showed the nanoparticles had regular and spherical morphology. Fourier transform infrared spectroscopy analysis demonstrated that CA was mainly encapsulated in the inner place of CSH/SBE-β-CD nanoparticles (CSNs). The enhanced thermal stability of the nanoparticles was found in differential scanning calorimeter. X-ray diffraction implied that CA-CSNs existed in the amorphous state. CA-CSNs had excellent slow release property. Further, the bacteriostatic effect of CA-CSNs was much better than that of CA and CSNs. All the results indicated that CSNs can be used as a promising carrier to encapsulate CA. PRACTICAL APPLICATIONS: CA is an effective antimicrobial and generally recognized as Safe-GRAS. CA also exhibits many other bioactivities and has been commonly used for digestive, cardiovascular and immune system diseases. However, CA is easy to be oxidized and volatilized during storage for poor water solubility. The nanoencapsulations display the capacities of enhancing solubility of bioactive compounds, protecting them from degradation, and prolonging their residence. In this manuscript, CA loaded nanoparticles were investigated. The results suggested that the nanoencapsulation could benefit for improving water solubility and stability of CA. This strategy could be helpful for its application and development in food preservation.

Preparation, Characterization, and Properties of Inclusion Complexes of Balofloxacin with Cyclodextrins

The study mainly aimed to improve the aqueous solubility of Balofloxacin (BLFX) by preparing the inclusion complexes (ICs) of BLFX with cyclodextrins (CDs). In this study, ICs in solid state were obtained by using beta-CD (β-CD), 2-hydroxypropyl-β-CD (HP-β-CD), 2, 6-dimethyl-β-CD (DM-β-CD) through a freeze-drying technique. The formation of ICs was confirmed through Fourier-transform infrared spectroscopy, differential scanning calorimetry, powder X-ray diffraction, nuclear magnetic resonance, and scanning electron microscopy. Results demonstrated that the water solubility and dissolution rates of three ICs were distinctly improved than that of parent BLFX. Bacteriostatic experiment manifested that the antibacterial effect of BLFX was not inhibited after encapsulation in CDs. The damage of BLFX to kidney and liver cells was reduced. Consequently, successful preparation of the ICs of BLFX with CDs provided possibility for devising new dosage form of BLFX, which held great promise for further applications in clinical fields.

The wound healing and antibacterial potential of triple-component nanocomposite (chitosan-silver-sericin) films loaded with moxifloxacin

AIM

The current study reports the development and evaluation of chitosan-sericin-silver nanocomposite (CSSN) films without and with moxifloxacin (Mox).

METHODOLOGY

The film preparation method involved the in-situ synthesis of silver nanoparticles within the chitosan-sericin colloidal composite followed by preparation into a film by solvent casting technique. In-situ formation and the particle size analysis of the silver nanoparticles was performed via UV-Visible and zeta-size spectrometer. The prepared films were tested for swelling ratio, contents uniformity, in-vitro Mox release, and permeation analysis. The morphological (SEM), elemental (EDX), spectral (FT-IR), structural (XRD), and thermal (TGA and DSC) properties of the composites were also inspected. The antibacterial activity of the CSSN films was performed against seven pathogenic bacterial strains including five ATCC and two clinical strains. The potential wound healing activity of the composite films was evaluated on burn wound model induced in Sprague Dawley male rats.

RESULTS

The prepared films displayed good swelling profile with a sustained in-vitro Mox release and permeation profile; attaining maximum of 78.57% (CSSM3) release and 55.05% (CSSM1) permeation (CSSM1) in 24 h. The prepared films, particularly the Mox-loaded CSSN films displayed a promising antibacterial activity against all the tested strains with the activity being highest against MRSA (clinical isolates). The prepared films indicated a remarkable wound healing applications with successful fibrosis, collagen reorganization, neovascularization, and mild epidermal regeneration after 7 days of treatment with no silver ions detection in animal's blood.

CONCLUSION

The obtained findings strongly suggest the use of the prepared novel composite dressing for wound care applications.

Chiral separation of rasagiline using sulfobutylether-β-cyclodextrin: capillary electrophoresis, NMR and molecular modeling study

Pressure-assisted stereospecific capillary electrophoresis method was developed for the determination of enantiomeric purity of the antiparkinsonian agent (R)-rasagiline. The optimized method, 50 mM glycine-HCl buffer pH 2, supplied with 30 mM sulfobutylether-β-cyclodextrin, at 35°C, applying 12 kV in reversed polarity, and -8 mbar pressure (vacuum), short-end injection with -25 mbar × 2 s, was successful for baseline separation of rasagiline enantiomers (R_s = 3.5 ± 0.1) in a short analysis time. The method was validated according to current guidelines and proved to be reliable, linear, precise and accurate for determination of 0.15% S-enantiomer as chiral impurity in R-rasagiline sample, as well as quantification of the eutomer. Method application was tested on a commercial tablet formulation. Determination of spatial structure of diastereomeric associates was based on ¹ H and 2D ROESY NMR, indicating that the aromatic moiety of the molecule can enter the cyclodextrin cavity. NMR titration and molecular modeling revealed that S-rasagiline formed a more stable inclusion complex with sulfobutylether-β-cyclodextrin, than its antipode, which is in agreement with electrophoretic results.

Nepafenac-Loaded Cyclodextrin/Polymer Nanoaggregates: A New Approach to Eye Drop Formulation

The topical administration route is commonly used for targeting therapeutics to the eye; however, improving the bioavailability of drugs applied directly to the eye remains a challenge. Different strategies have been studied to address this challenge. One of them is the use of aggregates that are formed easily by self-assembly of cyclodextrin (CD)/drug complexes in aqueous solution. The aim of this study was to design a new eye drop formulation based on aggregates formed between CD/drug complexes. For this purpose, the physicochemical properties of the aggregates associated with six CDs and selected water-soluble polymers were analysed. Complex formation was studied using differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR) and ¹H nuclear magnetic resonance spectroscopy (¹H-NMR). Results showed that HPβCD performed best in terms of solubilization, while γCD performed best in terms of enhancing nanoaggregate formation. Formation of inclusion complexes was confirmed by DSC, FT-IR and ¹H-NMR studies. A mixture of 15% (w/v) γCD and 8% (w/v) HPβCD was selected for formulation studies. It was concluded that formulations with aggregate sizes less than 1 µm and viscosity around 10–19 centipoises can be easily prepared using a mixture of CDs. Formulations containing polymeric drug/CD nanoaggregates represent an interesting strategy for enhanced topical delivery of nepafenac.