Comparative Evaluation of Ibuprofen/β-Cyclodextrin Complexes Obtained by Supercritical Carbon Dioxide and Other Conventional Methods

Recent Advances in the Pharmaceutical and Biomedical Applications of Cyclodextrin-Capped Gold Nanoparticles

The real problem in pharmaceutical preparation is drugs' poor aqueous solubility, low permeability through biological membranes, and short biological t_1/2. Conventional drug delivery systems are not able to overcome these problems. However, cyclodextrins (CDs) and their derivatives can solve these challenges. This article aims to summarize and review the history, properties, and different applications of cyclodextrins, especially the ability of inclusion complex formation. It also refers to the effects of cyclodextrin on drug solubility, bioavailability, and stability. Moreover, it focuses on preparing and applying gold nanoparticles (AuNPs) as novel drug delivery systems. It also studies the uses and effects of cyclodextrins in this field as novel drug carriers and targeting devices. The system formulated from AuNPs linked with CD molecules combines the advantages of both CD and AuNPs. Cyclodextrins benefit in increasing aqueous drug solubility, loading capacity, stability, and size control of gold NPs. Also, AuNPs are applied as diagnostic and therapeutic agents because of their unique chemical properties. Plus, AuNPs possess several advantages such as ease of detection, targeted and selective drug delivery, greater surface area, high loading efficiency, and higher stability than microparticles. In the present article, we tried to present the potential pharmaceutical applications of CD-derived AuNPs in biomedical applications including antibacterial, anticancer, gene-drug delivery, and various targeted drug delivery applications. Also, the article highlighted the role of CDs in the preparation and improvement of catalytic enzymes, the formation of self-assembling molecular print boards, the fabrication of supramolecular functionalized electrodes, and biosensors formation.

Simultaneous Removal of Heavy Metals and Ciprofloxacin Micropollutants from Wastewater Using Ethylenediaminetetraacetic Acid-Functionalized β-Cyclodextrin-Chitosan Adsorbent

The current study pertains to the synthesis of an EDTA-functionalized β-cyclodextrin-chitosan (β-CD-CS-EDTA) composite via a two-step process for the adsorptive removal of toxic heavy metallic ions (i.e., Pb(II), Cu(II), and Ni(II)) and antibiotic micropollutant, i.e., ciprofloxacin (CIP), from water. Different batch adsorption experiments such as pH, reaction time and initial pollutant concentration effects were carried out to identify the adsorption condition to attain the maximum removal efficiency. Kinetics results fit well with the pseudo-second order (PSO) kinetics model for both inorganic and organic pollutants. However, adsorption of heavy metal ions to the adsorbent was faster than that of CIP. Isotherms results showed excellent monolayer adsorption capacities of 330.90, 161, and 118.90 mg g^-1 for Pb(II), Cu(II), and Ni(II), respectively, with a heterogeneous adsorption capacity of 25.40 mg g^-1 for CIP. The adsorption mechanism was investigated using energy dispersive X-ray (EDX), elemental mapping, and Fourier transform infrared (FTIR) techniques. More significantly, the synthesized adsorbent gave good removal efficiencies when it was applied to simultaneously adsorb metal ions and CIP from real wastewater. Furthermore, excellent reusability could be obtained, making it a viable alternative to remove the inorganic and organic micropollutants for wastewater treatment.

Spray dried nanospheres for inclusion complexes of cefpodoxime proxetil with β-cyclodextrin, 2-hydroxypropyl-β-cyclodextrin and methyl-β-cyclodextrin: improved dissolution and enhanced antibacterial activity

OBJECTIVE

The aim of the current research was the development hard cellulose capsules containing cefpodoxime proxetil (CEF) (BCS-Class II) encapsulated nanospheres of inclusion complexes with β-CD, HP-β-CD and M-β-CD for efficient antibacterial therapy.

SIGNIFICANCE

The reason for this phenomenon is to bring an innovative approach to effective oral antimicrobial therapy with hard cellulose capsules containing spray dried nanospheres of CEF with β-CD, HP-β-CD and M-β-CD by means of increased solubility, dissolution rate and improved antibacterial efficiency with lower oral dose.

METHODS

Phase solubility analyses was performed to evaluate the drug/CD interaction, involving the stoichiometry and apparent stability constant. Following the preparation of inclusion complexes by spray-drying method, complexes were characterized for physical, solid-state and microbiological analyses. In vitro dissolution from hard cellulose capsules containing CEF and CEF/β-CD, CEF/HP-β-CD and CEF/M-β-CD complexes were performed.

RESULTS

According to AL type phase solubility curves, complexes were formulated as 1:1 molar ratio. The solubility of pure CEF was determined as 0.241 ± 0.002 mg mL-1, the solubility of inclusion complexes increased solubility from 3 to 5 times. The strong host-guest interaction was confirmed for CEF/HP-β-CD and CEF/M-β-CD complexes with SEM, DSC, FT-IR and 1H-NMR analyses. Inclusion complexes were more efficient on bacterial cells (2-4 fold) than pure CEF both Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae. Hard-cellulose capsules filled with inclusion complexes exhibited significantly faster release than unprocessed CEF.

CONCLUSION

Hard-cellulose capsules containing CEF/HP-β-CD and CEF/M-β-CD complexes appear to be superior alternative to commercially available CEF tablets for effective antibacterial therapy.

Supercritical Carbon Dioxide as a Green Alternative to Achieve Drug Complexation with Cyclodextrins

Cyclodextrins are widely used in pharmaceutics to enhance the bioavailability of many drugs. Conventional drug/cyclodextrin complexation techniques suffer from many drawbacks, such as a high residual content of toxic solvents in the formulations, the degradation of heat labile drugs and the difficulty in controlling the size and morphology of the product particles. These can be overcome by supercritical fluid technology thanks to the outstanding properties of supercritical CO₂ (scCO₂) such as its mild critical point, its tunable solvent power, and the absence of solvent residue after depressurization. In this work the use of scCO₂ as an unconventional medium to achieve the complexation with native and substituted cyclodextrins of over 50 drugs, which belong to different classes, are reviewed. This can be achieved with different approaches such as the “supercritical solvent impregnation” and “particle-formation” techniques. The different techniques are discussed to point out how they affect the complexation mechanism and efficiency, the physical state of the drug as well as the particle size distribution and morphology, which finally condition the release kinetics and drug bioavailability. When applicable, the results obtained for the same drug with various cyclodextrins, or different complexation techniques are compared with those obtained with conventional approaches.

Controlled delivery of ibuprofen from poly(vinyl alcohol)-poly(ethylene glycol) interpenetrating polymeric network hydrogels

Hydrogels composed of poly(vinyl alcohol) (PVA) and poly(ethylene glycol) (PEG) were synthesized using glutaraldehyde as crosslinker and investigated for controlled delivery of the common anti-inflammatory drug, ibuprofen (IBF). To regulate the drug delivery, solid inclusion complexes (ICs) of IBF in β–cyclodextrin (β–CD) were prepared and added to the hydrogels. The ICs were prepared by the microwave irradiation method, which is more environmentally benign. The formation of IC was confirmed by various analytical techniques and the synthesized hydrogels were also characterized. Controlled release of drug was achieved from the hydrogels containing the ICs in comparison to the rapid release from hydrogels containing free IBF. The preliminary kinetic analysis emphasized the crucial role of β–CD in the drug release process that influences the polymer relaxation, thereby leading to prolonged release. The cytotoxicity assay validated the hydrogels as non-toxic in nature and hence can be utilized for controlled delivery of IBF.

One-pot synthesis of trifunctional chitosan-EDTA-β-cyclodextrin polymer for simultaneous removal of metals and organic micropollutants

The global contamination of water resources with inorganic and organic micropollutants, such as metals and pharmaceuticals, poses a critical threat to the environment and human health. Herein, we report on a bio-derived chitosan-EDTA-β-cyclodextrin (CS-ED-CD) trifunctional adsorbent fabricated via a facile and green one-pot synthesis method using EDTA as a cross-linker, for the adsorption of toxic metals and organic micropollutants from wastewater. In this system, chitosan chain is considered as the backbone, and the immobilized cyclodextrin cavities capture the organic compounds via host-guest inclusion complexation, while EDTA-groups complex metals. The thoroughly characterized CS-ED-CD was employed for batch adsorption experiments. The adsorbent displayed a monolayer adsorption capacity of 0.803, 1.258 mmol g-1 for Pb(II) and Cd(II) respectively, while a heterogeneous sorption capacity of 0.177, 0.142, 0.203, 0.149 mmol g-1 for bisphenol-S, ciprofloxacin, procaine, and imipramine, respectively. The adsorption mechanism was verified by FT-IR and elemental mapping. Importantly, the adsorbent perform is effective in the simultaneous removal of metals and organic pollutants at environmentally relevant concentrations. All these findings demonstrate the promise of CS-ED-CD for practical applications in the treatment of micropollutants. This work adds a new insight to design and preparation of efficient trifunctional adsorbents from sustainable materials for water purification.

Supercritical Fluid Technology: An Emphasis on Drug Delivery and Related Biomedical Applications

During the past few decades, supercritical fluid (SCF) has emerged as an effective alternative for many traditional pharmaceutical manufacturing processes. Operating active pharmaceutical ingredients (APIs) alone or in combination with various biodegradable polymeric carriers in high-pressure conditions provides enhanced features with respect to their physical properties such as bioavailability enhancement, is of relevance to the application of SCF in the pharmaceutical industry. Herein, recent advances in drug delivery systems manufactured using the SCF technology are reviewed. We provide a brief description of the history, principle, and various preparation methods involved in the SCF technology. Next, we aim to give a brief overview, which provides an emphasis and discussion of recent reports using supercritical carbon dioxide (SC-CO2 ) for fabrication of polymeric carriers, for applications in areas related to drug delivery, tissue engineering, bio-imaging, and other biomedical applications. We finally summarize with perspectives.

Design of experiments for microencapsulation applications: A review

Microencapsulation techniques have been intensively explored by many research sectors such as pharmaceutical and food industries. Microencapsulation allows to protect the active ingredient from the external environment, mask undesired flavours, a possible controlled release of compounds among others. The purpose of this review is to provide a background of design of experiments in microencapsulation research context. Optimization processes are required for an accurate research in these fields and therefore, the right implementation of micro-sized techniques at industrial scale. This article critically reviews the use of the response surface methodologies in pharmaceutical and food microencapsulation research areas. A survey of optimization procedures in the literature, in the last few years is also presented.

Inclusion complexes of hydrochlorothiazide and β-cyclodextrin: Physicochemical characteristics, in vitro and in vivo studies

Hydrochlorothiazide is a thiazide diuretic widely used in clinics to treat arterial hypertension. It is a class IV drug according to the Biopharmaceutical Classification System, that is, it presents low solubility and low permeability and, consequently, low absorption in the gastrointestinal tract. As a strategy to improve stability and biopharmaceutical properties of hydrochlorothiazide, the use of cyclodextrins to produce inclusion complexes, applying different methods, was investigated. In the phase solubility studies, β-cyclodextrin was identified as the cyclodextrin which provided the most promising results in terms of the solubilization of the drug. The thermal analysis verified the interaction between hydrochlorothiazide and β-cyclodextrin, indicating the formation of inclusion complexes, and the thermal stability varied according to the preparation technique. The physicochemical characterization showed that in the inclusion complexes obtained by co-evaporation, kneading followed by freeze-drying and kneading followed by spray-drying the hydrochlorothiazide complexation mostly occurred with different degrees of amorphization and the drug solubility was improved. These three inclusion complexes presented better in vitro characteristics and the inclusion complex obtained by kneading followed by freeze-drying increased the in vivo diuretic activity of the drug accompanied by significant effects on natriuresis, kaliuresis and chloriuresis. The inclusion complex formation was effective in improving the biopharmaceutical properties of hydrochlorothiazide and protecting the drug from hydrolysis. This paper describes an important alternative approach to the development of liquid pharmaceutical formulations to pediatric administration, a real need of the current pharmaceutical market.

Full factorial design optimization of anti-inflammatory drug release by PCL-PEG-PCL microspheres

A biodegradable triblock poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) copolymer was successfully synthesized by ring-opening polymerization of ε-caprolactone, and was characterized by intrinsic viscosimetry, (1)H nuclear magnetic resonance, infrared spectroscopy and X-ray diffraction. Copolymer microparticles loaded with ibuprofen were prepared by an oil-in-water (o/w) emulsion solvent evaporation process. They were carefully weighted and characterized through their zeta potential. In this work, 4 selected process parameters (shaking speed X1, time of contact X2, poly(vinyl alcohol) concentration X3, and ibuprofen concentration X4) were adjusted at 2 different values. For each of the 16 experimental conditions, repeated twice, the drug encapsulation efficiency of the microspheres was determined, according to the following definition: EE (X1, X2, X3, X4)=mass of encapsulated ibuprofen/total weight of ibuprofen. A "full factorial design method" was applied to analyze the results statistically according to a polynomial fit and to determine the optimal conditions for the microencapsulation of the ibuprofen through an accurate statistical protocol. The microparticles obtained exhibit a spherical shape as shown by electron microscopy.

EDTA-Cross-Linked β-Cyclodextrin: An Environmentally Friendly Bifunctional Adsorbent for Simultaneous Adsorption of Metals and Cationic Dyes

The discharge of metals and dyes poses a serious threat to public health and the environment. What is worse, these two hazardous pollutants are often found to coexist in industrial wastewaters, making the treatment more challenging. Herein, we report an EDTA-cross-linked β-cyclodextrin (EDTA-β-CD) bifunctional adsorbent, which was fabricated by an easy and green approach through the polycondensation reaction of β-cyclodextrin with EDTA as a cross-linker, for simultaneous adsorption of metals and dyes. In this setting, cyclodextrin cavities are expected to capture dye molecules through the formation of inclusion complexes and EDTA units as the adsorption sites for metals. The adsorbent was characterized by FT-IR, elemental analysis, SEM, EDX, ζ-potential, and TGA. In a monocomponent system, the adsorption behaviors showed a monolayer adsorption capacity of 1.241 and 1.106 mmol g(-1) for Cu(II) and Cd(II), respectively, and a heterogeneous adsorption capacity of 0.262, 0.169, and 0.280 mmol g(-1) for Methylene Blue, Safranin O, and Crystal Violet, respectively. Interestingly, the Cu(II)-dye binary experiments showed adsorption enhancement of Cu(II), but no significant effect on dyes. The simultaneous adsorption mechanism was further confirmed by FT-IR, thermodynamic study, and elemental mapping. Overall, its facile and green fabrication, efficient sorption performance, and excellent reusability indicate that EDTA-β-CD has potential for practical applications in integrative and efficient treatment of coexistenting toxic pollutants.

Investigation of β-cyclodextrin-norfloxacin inclusion complexes. Part 1. Preparation, physicochemical and microbiological characterization

INTRODUCTION

Drugs classified as class IV by the Biopharmaceutical Classification System present significant problems in relation to effective oral administration. In the case of antibiotics, the subsequently high doses required can enhance the emergence of microorganism resistance and lead to a low rate of patient treatment adherence.

OBJECTIVE

In an attempt to improve physicochemical properties and microbiological activity of norfloxacin, the aim of this study was to investigate different methods (coevaporation, kneading followed by freeze-drying or spray-drying) to obtain complexes of norfloxacin and different cyclodextrins.

METHODS

Guest-host interactions were investigated through a complete physical-chemical characterization and the dissolution profile and microbiological activity were determined.

RESULTS

The formation of a complex of norfloxacin and β-cyclodextrin (1:1), obtained by kneading followed by freeze drying, led to increased drug solubility, which could maximize the oral drug absorption.

CONCLUSION

Moreover, the microbiological activity was enhanced by around 23.3%, demonstrating that the complex formed could represent an efficient drug delivery system.

Characterization of the host-guest complex of a curcumin analog with β-cyclodextrin and β-cyclodextrin-gemini surfactant and evaluation of its anticancer activity

Background

Curcumin analogs, including the novel compound NC 2067, are potent cytotoxic agents that suffer from poor solubility, and hence, low bioavailability. Cyclodextrin-based carriers can be used to encapsulate such agents. In order to understand the interaction between the two molecules, the physicochemical properties of the host–guest complexes of NC 2067 with β-cyclodextrin (CD) or β-cyclodextrin–gemini surfactant (CDgemini surfactant) were investigated for the first time. Moreover, possible supramolecular structures were examined in order to aid the development of new drug delivery systems. Furthermore, the in vitro anticancer activity of the complex of NC 2067 with CDgemini surfactant nanoparticles was demonstrated in the A375 melanoma cell line.

Methods

Physicochemical properties of the complexes formed of NC 2067 with CD or CDgemini surfactant were investigated by synchrotron-based powder X-ray diffraction, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. Synchrotron-based small- and wide-angle X-ray scattering and size measurements were employed to assess the supramolecular morphology of the complex formed by NC 2067 with CDgemini surfactant. Lastly, the in vitro cell toxicity of the formulations toward A375 melanoma cells at various drug-to-carrier mole ratios were measured by cell viability assay.

Results

Physical mixtures of NC 2067 and CD or CDgemini surfactant showed characteristics of the individual components, whereas the complex of NC 2067 and CD or CDgemini surfactant presented new structural features, supporting the formation of the host–guest complexes. Complexes of NC 2067 with CDgemini surfactants formed nanoparticles having sizes of 100–200 nm. NC 2067 retained its anticancer activity in the complex with CDgemini surfactant for different drug-to-carrier mole ratios, with an IC₅₀ (half-maximal inhibitory concentration) value comparable to that for NC 2067 without the carrier.

Conclusion

The formation of host–guest complexes of NC 2067 with CD or CDgemini surfactant has been confirmed and hence the CDgemini surfactant shows good potential to be used as a delivery system for anticancer agents.

Temperature effect on the vibrational dynamics of cyclodextrin inclusion complexes: investigation by FTIR-ATR spectroscopy and numerical simulation

The vibrational dynamics of solid inclusion complexes of the nonsteroidal anti-inflammatory drug Ibuprofen (IBP) with beta-cyclodextrin (beta-CD) and methyl-beta-cyclodextrin (Me-beta-CD) has been investigated by using attenuated total reflection-Fourier transform infrared FTIR-ATR spectroscopy, in order to monitor the changes induced, as a consequence of complexation, on the vibrational spectrum of IBP, in the wavenumber range 600-4000 cm(-1). Quantum chemical calculations were performed on monomeric and dimeric structures of IBP, derived from symmetric hydrogen bonding of the two carboxylic groups, in order to unambiguously assign some characteristic IR bands in the IBP spectrum. The evolution in temperature from 250 to 340 K of the C horizontal lineO stretching vibration, described by a best-fit procedure, allowed us to extract the thermodynamic parameter DeltaH associated to the binding of IBP with betaCDs in the solid phase. By comparing these results, Me-beta-CD has been shown to be the most effective carrier for IBP.

Effect of Ultrasound on the Compaction of Ibuprofen/Isomalt Systems

Six mixtures, containing 10, 20 and 30% w/w ibuprofen and isomalt, were compacted by a traditional or ultrasound-assisted machine and analysed by means of thermal (DSC and TGA) and micro-spectrometry (Raman and FT-IR) techniques. Ultrasound discharge causes melting of ibuprofen powder, transforming into a paste that could not assume the shape of a tablet; when in mixture with isomalt, thermal events, occurring during ultrasound compaction, change the appearance of the particles formed by milling the tablets obtained this way and SEM photos reveal a dramatic reduction of the particle size and changes due to a possible ibuprofen re-crystallization. Raman and FT-IR spectra of small portions of the surface and of the bulk, using characteristic peaks for identification, reveal that in ultrasound-compacted tablets ibuprofen partially disappears from the top face of the tablet.

One-pot regioselective synthesis of 2I,3I-O-(o-xylylene)-capped cyclomaltooligosaccharides: tailoring the topology and supramolecular properties of cyclodextrins

The alpha,alpha'-dibromo-o-xylylene cap has been installed at the secondary hydroxyls of a single glucopyranosyl residue in cyclodextrins in one pot and with total regioselectivity; the resulting cyclic ether acts as a removable hinge, allowing selective elaboration of the secondary face and modulating both the self-association and the inclusion capabilities of the hosts.