Development and pharmacological evaluation of ropivacaine-2-hydroxypropyl-β-cyclodextrin inclusion complex

Sustained release local anesthetics for pain management: relevance and formulation approaches

This review attempted to ascertain the rationale for the formulation of sustained-release local anesthetics and summarize the various formulation approaches designed to date to achieve sustained and localized local analgesic effects. The incidence of pain, which is the concern of patients as well as health care professionals, is increasing due to accidents, surgical procedures, and other diseases. Local anesthetics can be used for the management of moderate to severe acute and chronic pain. They also allow regional analgesia, in situations where the cause and source of the pain are limited to a particular site or region, without the need for loss of consciousness or systemic administration of other analgesics thereby decreasing the risk of potential toxicities. Though they have an interesting antipain efficacy, the short duration of action of local anesthetics makes the need for their multiple injections or opioid adjuvants mandatory. To overcome this problem, different formulations are being designed that help achieve prolonged analgesia with a single dose of administration. Combination with adjuvants, liposomal formulations, lipid-based nanoparticles, thermo-responsive nanogels, microspheres, microcapsules, complexation with multivalent counterions and HP-β-CD, lipid-based nanoparticles, and bio-adhesive films, and polymeric matrices are among the approaches. Further safety studies are required to ensure the safe and effective utilization of sustained-release local anesthetics. Moreover, the release kinetics of the various formulations should be adequately established.

Cyclodextrins as Multi-Functional Ingredients in Dentistry

Cyclodextrins are present in a variety of oral hygiene compositions. The present work describes the role of cyclodextrins in several toothpastes and mouthwashes that are already available in the market, as well as their prospective use in other applications as investigated in studies in the literature. Moreover, cyclodextrins are under study for the development of materials used in various techniques of dental repair, such as fillings, cements and binders therein. Their role in each of the innovative materials is presented. Finally, the prospect of the use of cyclodextrin-based delivery systems for the oral cavity is introduced, with a focus on new cyclodextrin molecules with dual action as bone-targeting agents and osteogenic drugs, and on new cross-linked cyclodextrin particles with a high drug loading and sustained drug delivery profile for the treatment of diseases that require prolonged action, such as periodontitis. In conclusion, cyclodextrins are herein demonstrated to act as versatile and multi-action ingredients with a broad range of applications in dentistry.

Exploring the Inclusion Complex of an Anticancer Drug with β-Cyclodextrin for Reducing Cytotoxicity Toward the Normal Human Cell Line by an Experimental and Computational Approach

The toxicity of any drug against normal cells is a health hazard for all humans. At present, health and disease researchers from all over the world are trying to synthesize designer drugs with diminished toxicity and side effects. The purpose of the present study is to enhance the bioavailability and biocompatibility of gemcitabine (GEM) by decreasing its toxicity and reducing deamination during drug delivery by incorporating it inside the hydrophobic cavity of β-cyclodextrin (β-CD) without affecting the drug ability of the parent compound (GEM). The newly synthesized inclusion complex (IC) was characterized by different physical and spectroscopic techniques, thereby confirming the successful incorporation of the GEM molecule into the nanocage of β-CD. The molecular docking study revealed the orientation of the GEM molecule into the β-CD cavity (-5.40 kcal/mol) to be stably posed for ligand binding. Photostability studies confirmed that the inclusion of GEM using β-CD could lead to better stabilization of GEM (≥96%) for further optical and clinical applications. IC (GEM-β-CD) and GEM exhibited effective antibacterial and antiproliferative activities without being metabolized in a dose-dependent manner. The CT-DNA analysis showed sufficiently strong IC (GEM-β-CD) binding (Ka = 8.1575 × 1010), and this interaction suggests that IC (GEM-β-CD) may possibly exert its biological effects by targeting nucleic acids in the host cell. The newly synthesized biologically active IC (GEM-β-CD), a derivative of GEM, has pharmaceutical development potentiality.

Fabrication of fucoxanthin/2-hydroxypropyl-β-cyclodextrin inclusion complex assisted by ultrasound procedure to enhance aqueous solubility, stability and antitumor effect of fucoxanthin

Fucoxanthin (Fx) possesses multiple bioactivities such as antitumor, antioxidant and anti-inflammatory activities, but its application is limited due to the poor water solubility, low bioavailability, and instability to some external harsh conditions. In this study, a stable inclusion complex of Fx and 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD) was prepared with the aid of ultrasound, which was characterized by scanning electron microscope, Fourier transform infrared spectroscopy, powder X-ray diffraction, and differential scanning calorimetry techniques. The phase solubility analysis and absorption spectroscopy results showed that Fx formed stoichiometry 1:2 inclusion complex with 2-HP-β-CD, and this could be well proved by molecular simulation. Structural analyses and molecular docking study indicated that Fx was successfully encapsulated into the cavity of 2-HP-β-CD, promoting it soluble in water and stable against heat, storage and gastrointestinal environments. In addition, Fx/2-HP-β-CD inclusion complex exhibited excellent antitumor activity against HCT116 and Caco-2 cell lines with IC₅₀ values of 12.0 μΜ and 14.86 μΜ, respectively. Therefore, it could be a potentially promising way to promote the application of Fx in pharmaceuticals and functional foods by HP-β-CD encapsulation strategy.

Antinociceptive effects of bupivacaine and its sulfobutylether-β-cyclodextrin inclusion complex in orofacial pain

Bupivacaine hydrochloride (BVC) represents an option to produce long-lasting analgesia, and complexation in cyclodextrins has shown improvements in biopharmaceutical properties. This study aimed to characterize and test the cytotoxicity and antinociceptive effects of BVC complexed in sulfobutylether-β-cyclodextrin (SBEβCD). The kinetics and stoichiometry of complexation and BVC-SBEβCD association constant were evaluated by phase solubility study and Job's plot. Evidence of the BVC-SBEβCD complex formation was obtained from scanning electron microscopy (SEM), infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The cytotoxicity was evaluated in keratinocyte (HaCaT) and neuroblastoma (SH-SY5Y). Antinociceptive effects were registered via orofacial pain models: the formalin test, carrageenan-induced hyperalgesia, and postoperative pain (intraoral incision). The complex formation occurred at a 1:1 BVC-SBEβCD molar ratio, with a low association constant (13.2 M^-1). SEM, DSC, and FTIR results demonstrated the host-guest interaction. The IC_50% values determined in SH-SY5Y were 216 µM and 149 µM for BVC and BVC-SBEβCD, respectively (p < 0.05). There was no difference in HaCaT IC_50%. In orofacial pain model, BVC-SBEβCD significantly prolonged antinociceptive effect, in about 2 h, compared to plain BVC. SBEβCD can be used as a drug delivery system for bupivacaine, whereas the complex showed long-lasting analgesic effects.

A novel gedunin-2-hydroxypropyl-β-cyclodextrin inclusion complex improves anti-nociceptive and anti-inflammatory activities of gedunin in rodents

Gedunin is a bioactive compound, obtained from Entandrophragma angolense (EA), which has limited therapeutic usefulness due to poor aqueous solubility and first-pass effects. Cyclodextrins are cyclic oligosaccharides that form complexes with poorly soluble compounds, thus enhancing their pharmacological activity. In this article, we evaluated the pharmacological activities of gedunin-2-hydroxypropyl-β-cyclodextrin complex (GCD) in rodents. The antinociceptive activity of GCD (50, 100, 200 mg/kg) and Gedunin (50mg/kg) was tested in acetic acid-induced writhing and formalin-induced paw licking in mice. The anti-inflammatory activity was investigated in carrageenan-induced paw oedema and air pouch inflammation models in rats. Leucocytes counts, Tumour Necrosis Factor-alpha (TNF-α) level, nitric oxide, malondialdehyde, reduced glutathione, and myeloperoxidase enzyme activities were assessed in the air pouch exudate. The GCD (200mg/kg) significantly decreased writhing response, reduced licking duration and decreased oedema compared with gedunin and control. Exudate volume and leucocyte count were significantly reduced by GCD (200 mg/kg), it decreased myeloperoxidase activity and inhibited TNF-α release. The carrageenan-induced GSH depletion, increased malondialdehyde and nitrite levels were significantly reversed by GCD (200 mg/kg) relative to gedunin and control.  The GCD complex demonstrated significant antinociceptive and anti-inflammatory activities relative to gedunin alone via mechanisms associated with inhibition of oxidative stress and inflammation in rodents.

Nasal powders of quercetin-β-cyclodextrin derivatives complexes with mannitol/lecithin microparticles for Nose-to-Brain delivery: In vitro and ex vivo evaluation

Quercetin, a flavonoid with possible neuroprotective action has been recently suggested for the early-stage treatment of Alzheimer's disease. The low solubility and extended first pass effect render quercetin unsuitable for oral administration. Alternatively, brain targeting is more feasible with nasal delivery, by-passing, non-invasively, Blood-Brain Barrier and ensuring rapid onset of action. Aiming to increase quercetin's disposition into brain, nasal powders consisting of quercetin-cyclodextrins (methyl-β-cyclodextrin and hydroxypropyl-β-cyclodextrin) lyophilizates blended with spray-dried microparticles of mannitol/lecithin were prepared. Quercetin's solubility at 37 °C and pH 7.4 was increased 19-35 times when complexed with cyclodextrins. Blending lyophilizates in various ratios with mannitol/lecithin microparticles, results in powders with improved morphological characteristics as observed by X-ray Diffraction and Scanning Electron Microscopy analysis. In vitro characterization of these powders using Franz cells, revealed rapid dissolution and permeation 17 (methyl-β-cyclodextrin) to 48 (hydroxypropyl-β-cyclodextrin) times higher than that of pure quercetin. Ex vivo powders' transport across rabbit nasal mucosa was found more efficient in comparison with the pure Que. The overall better performance of quercetin-hydroxypropyl-β-cyclodextrin powders is confirmed by ex vivo experiments revealing amount of quercetin permeated ranging from 0.03 ± 0.01 to 0.22 ± 0.05 μg/cm² for hydroxypropyl-β-cyclodextrin and 0.022 ± 0.01 to 0.17 ± 0.04 μg/cm² for methyl-β-cyclodextrin powders, while the permeation of pure quercetin was negligible.

Characteristic of Cyclodextrins: Their Role and Use in the Pharmaceutical Technology

About 40% of newly-discovered entities are poorly soluble in water, and this may be an obstacle in the creation of new drugs. To address this problem, the present review article examines the structure and properties of cyclodextrins and the formation and potential uses of drug - cyclodextrin inclusion complexes. Cyclodextrins are cyclic oligosaccharides containing six or more D-(+)- glucopyranose units linked by α-1,4-glycosidic bonds, which are characterized by a favourable toxicological profile, low local toxicity and low mucous and eye irritability; they are virtually non-toxic when administered orally. They can be incorporated in the formulation of new drugs in their natural form (α-, β-, γ-cyclodextrin) or as chemically-modified derivatives. They may also be used as an excipient in drugs delivered by oral, ocular, dermal, nasal and rectal routes, as described in the present paper. Cyclodextrins are promising compounds with many beneficial properties, and their use may be increasingly profitable for pharmaceutical scientists.

Prolonged anesthesia and decreased toxicity of enantiomeric-excess bupivacaine loaded in ionic gradient liposomes

Bupivacaine is the most employed local anesthetic in surgical procedures, worldwide. Its systemic toxicity has directed the synthesis of the less toxic, S(-) enantiomer. This work describes a formulation of ionic gradient liposomes (IGL) containing _S75BVC, an enantiomeric excess mixture of 75% S(-) and 25% R(+) bupivacaine. IGL prepared with 250 mM (NH₄)₂SO₄ in the inner aqueous core of phosphatidylcholine and cholesterol (3:2 mol%) vesicles plus 0.5% _S75BVC showed average sizes of 312.5 ± 4.5 nm, low polydispersity (PDI < 0.18), negative zeta potentials (-14.2 ± 0.2 mV) and were stable for 360 days. The encapsulation efficiency achieved with IGL_S75BVC (%EE = 38.6%) was higher than with IGL prepared with racemic bupivacaine (IGL_RBVC, %EE = 28.3%). TEM images revealed spherical vesicles and µDSC analysis provided evidence on the interaction of the anesthetic with the lipid bilayer. Then, in vitro - release kinetics and cytotoxicity- and in vivo - toxic effects in Zebrafish and biochemical/histopathological analysis plus analgesia in Wistar rats - tests were performed. IGL_S75BVC exhibited negligible toxicity against Schwann cells and Zebrafish larvae, and it did not affect biochemical markers or the morphology of rat tissues (heart, brain, cerebellum, sciatic nerve). The in vitro release of _S75BVC from IGL was extended from 4 to 24 h, justifying the prolonged anesthetic effect measured in rats (~9 h). The advantages of IGL_S75BVC formulation over IGL_RBVC and plain bupivacaine formulations (prolonged anesthesia, preferential sensorial blockade, and no toxicity) confirm its potential for clinical use in surgical anesthesia.

Effects of 2-Hydroxypropil-Β-Cyclodextrin-Lidocaine on Tumor Growth and Inflammatory Response

BACKGROUND

Antiproliferative and cytotoxic effects of lidocaine have been reported in tumor cells. However, the use of these drugs is restricted due to their short action with rapid dispersion from the injected site. The complexation of local anesthetics in 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) is able to improve pharmacological features.

OBJECTIVE

This study evaluated the antitumor effects of lidocaine and the complex HP-β-CD-lidocaine (HP-β-CD-lido).

METHODS

In vitro;, human adenocarcinoma (HeLa) and keratinocytes (HaCaT) were exposed to lidocaine formulations and cell viability, proliferation and apoptosis induction were measured. In vivo;, Walker 256 carcinoma cells were subcutaneously injected into the plantar region of the rat right hind paw. The animals were treated with a local application of 5% lidocaine or 5% HP-β-CD-lido. Doxorubicin (3 mg/Kg/day, intraperitoneal) was used as a positive control. Edema sizes were measured daily and the release of cytokines (TNF-α, IL-1α and CXCL-1) and prostaglandin E2 was evaluated. Histological analysis was also performed.

RESULTS

HaCaT IG50 values were 846 μM and 2253 μM for lido and HP-β-CD-lido, respectively. In HeLa cells, the IG50 was 1765 μM for lido and 2044 μM for HP-β-CD-lido. Lidocaine formulations significantly reduced the paw edema on day 6 after Walker 256 cells inoculation. However, there were no differences in the release of inflammatory mediators in comparison to the control group.

CONCLUSION

Lidocaine formulations were able to reduce the edema in vivo;, without affecting the tumor- induced inflammatory response. The antiproliferative effects of lidocaine formulations may have contributed to tumor reduction.

Physicochemical characterization and cytotoxicity of articaine-2-hydroxypropyl-β-cyclodextrin inclusion complex

Articaine (ATC) is one of the most widely used local anesthetics in dentistry. Despite its safety, local toxicity has been reported. This study aimed to develop an ATC-2- hydroxypropyl-β-cyclodextrin inclusion complex (ATC HPβCD) and to assess its toxicity in vitro. The inclusion complex was performed by solubilization, followed by a fluorimetric and job plot assay to determine the complex stoichiometry. Scanning electron microscopy, DOSY- 1 H-NMR, differential scanning calorimetry (DSC), and sustained release kinetics were used to confirm the inclusion complex formation. In vitro cytotoxicity was analyzed by MTT assay and immunofluorescence in HGF cells. Fluorimetric and job plot assay determined the inclusion complex stoichiometry (ATC:HPβCD = 1:1) and complex formation time (400 min), as indicated by a strong host/guest interaction (Ka = 117.8 M - 1), complexed fraction (f = 41.4%), and different ATC and ATC HPβCD melting points (172 °C e 235 °C, respectively). The mean of cell viability was 31.87% and 63.17% for 20-mM ATC and 20-mM ATC HPβCD, respectively. Moreover, remarkable cell toxicity was observed with free ATC by immunofluorescence. These results indicate the ATC HPβCD complex could be used to improve the safety of ATC. Further research are needed to establish the anesthetic safety and effectiveness in vivo .

Utilization of Water-Soluble Aminoethylamino-β-Cyclodextrin in the Pfitzinger Reaction-Catalyzed to the Synthesis of Diversely Functionalized Quinaldine

In this study we describe the use of an aminoethylamino-β-cyclodextrin (AEA-β-CD) as a supramolecular homogeneous catalyst for the synthesis of a series of diversely substituted quinaldine derivatives which are medicinally important, via Pfitzinger reaction. This supramolecular catalyst exhibited remarkable catalytic activity with high substrate scope to achieve the synthetic targets in good to excellent yield, 69-92%. The structural and morphological properties of the synthesized AEA-β-CD were determined through MALDI-TOF mass spectrometry, NMR, FT-IR, and SEM analysis. Possible reaction mechanisms were determined through molecular host-guest complexation and proposed based on 2D NMR (ROESY) spectroscopy, FT-IR, FE-SEM, and DSC.

Anaesthetic benefits of a ternary drug delivery system (Ropivacaine-in-Cyclodextrin-in-Liposomes): in-vitro and in-vivo evaluation

OBJECTIVES

To evaluate whether a ternary system composed of hydroxypropyl-β-cyclodextrin (HP-βCD) further encapsulated into egg phosphatidylcholine liposomes (LUV) could prolong the action and reduce the toxicity of ropivacaine (RVC).

METHODS

Dynamic light scattering and NMR were used to characterize the inclusion complex (RVC : HP-βCD), liposomal (RVC : LUV) and ternary (LUV : RVC : HP-βCD) systems containing 0.25% RVC. Their encapsulation efficiency, release kinetics, in-vitro cytotoxicity and in-vivo anaesthetic effect (paw-withdraw tests in mice) were also evaluated.

KEY FINDINGS

1 : 1 RVC : HP-βCD inclusion complex was encapsulated in liposomes (220.2 ± 20.3 nm size, polydispersity <0.25, zeta potentials = -31.7 ± 1.4 mV). NMR (diffusion-ordered spectroscopy (DOSY)) revealed stronger anaesthetic binding to LUV : RVC : HP-βCD (K_a  = 342 m^-1 ) than to RVC : HP-βCD (K_a  = 128 m^-1 ) or liposomal formulation (K_a  = 22 m^-1 ). The formulations promoted in-vitro sustained drug release and partially reverted the cytotoxicity of RVC against 3T3 fibroblasts in the profile: LUV : RVC : HP-βCD ≥ RVC : HP-βCD > RVC : LUV. Accordingly, in-vivo sensory block of free RVC (180 min) was prolonged ca. 1.7 times with the ternary system and RVC : HP-βCD (300 min) and 1.3 times with RVC : LUV (240 min).

CONCLUSIONS

These results confirm the suitability of this double-carrier system in clinical practice, to decrease the toxicity and prolong the anaesthesia time evoked by RVC.

Enhanced Solubility and Anticancer Potential of Mansonone G By β-Cyclodextrin-Based Host-Guest Complexation: A Computational and Experimental Study

Mansonone G (MG), a plant-derived compound isolated from the heartwood of Mansonia gagei, possesses a potent antitumor effect on several kinds of malignancy. However, its poor solubility limits the use for practical applications. Beta-cyclodextrin (βCD), a cyclic oligosaccharide composed of seven (1→4)-linked α-D-glucopyranose units, is capable of encapsulating a variety of poorly soluble compounds into its hydrophobic interior. In this work, we aimed to enhance the water solubility and the anticancer activity of MG by complexation with βCD and its derivatives (2,6-di-O-methyl-βCD (DMβCD) and hydroxypropyl-βCD). The 90-ns molecular dynamics simulations and MM/GBSA-based binding free energy results suggested that DMβCD was the most preferential host molecule for MG inclusion complexation. The inclusion complex formation between MG and βCD(s) was confirmed by DSC and SEM techniques. Notably, the MG/βCDs inclusion complexes exerted significantly higher cytotoxic effect (~2–7 fold) on A549 lung cancer cells than the uncomplexed MG.

Inclusion Complexes of Melphalan with Gemini-Conjugated β-Cyclodextrin: Physicochemical Properties and Chemotherapeutic Efficacy in In-Vitro Tumor Models

β-cyclodextrin (βCD) has been widely explored as an excipient for pharmaceuticals and nutraceuticals as it forms stable host–guest inclusion complexes and enhances the solubility of poorly soluble active agents. To enhance intracellular drug delivery, βCD was chemically conjugated to an 18-carbon chain cationic gemini surfactant which undergoes self-assembly to form nanoscale complexes. The novel gemini surfactant-modified βCD carrier host (hereafter referred to as 18:1βCDg) was designed to combine the solubilization and encapsulation capacity of the βCD macrocycle and the cell-penetrating ability of the gemini surfactant conjugate. Melphalan (Mel), a chemotherapeutic agent for melanoma, was selected as a model for a poorly soluble drug. Characterization of the 18:1βCDg-Mel host–guest complex was carried out using 1D/2D ¹H NMR spectroscopy and dynamic light scattering (DLS). The 1D/2D NMR spectral results indicated the formation of stable and well-defined 18:1βCDg-Mel inclusion complexes at the 2:1 host–guest mole ratio; whereas, host–drug interaction was attenuated at greater 18:1βCDg mole ratio due to hydrophobic aggregation that accounts for the reduced Mel solubility. The in vitro evaluations were performed using monolayer, 3D spheroid, and Mel-resistant melanoma cell lines. The 18:1βCDg-Mel complex showed significant enhancement in the chemotherapeutic efficacy of Mel with 2–3-fold decrease in Mel half maximal inhibitory concentration (IC₅₀) values. The findings demonstrate the potential applicability of the 18:1βCDg delivery system as a safe and efficient carrier for a poorly soluble chemotherapeutic in melanoma therapy.

Inclusion Complexes of β and HPβ-Cyclodextrin with α, β Amyrin and In Vitro Anti-Inflammatory Activity

α, β amyrin (ABAM) is a natural mixture of pentacyclic triterpenes that has a wide range of biological activities. ABAM is isolated from the species of the Burseraceae family, in which the species Protium is commonly found in the Amazon region of Brazil. The aim of this work was to develop inclusion complexes (ICs) of ABAM and β-cyclodextrin (βCD) and hydroxypropyl-β-cyclodextrin (HPβCD) by physical mixing (PM) and kneading (KN) methods. Interactions between ABAM and the CD’s as well as the formation of ICs were confirmed by physicochemical characterization in the solid state by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetry (TG) and differential scanning calorimetry (DSC). Physicochemical characterization indicated the formation of ICs with both βCD and HPβCD. Such ICs were able to induce changes in the physicochemical properties of ABAM. In addition, the formation of ICs with cyclodextrins showed to be an effective and promising alternative to enhance the anti-inflammatory activity and safety of ABAM.

An Amino-Chain Modified β-cyclodextrin: A Supramolecular Ligand for Pd(OAc)2 Acceleration in Suzuki–Miyaura Coupling Reactions in Water

A well-designed and synthesized water-soluble class of β-cyclodextrin supported palladium complex PdLn@Et-β-CD could efficiently validate high catalytic activity and act as a supramolecular platform for phosphine-free Suzuki–Miyaura cross‐coupling reactions between arylboronic acid/ arylboronic ester and aryl halides in water under mild conditions. The presented novel PdLn@Pr-β-CD complex catalyst was characterized by NMR, XRD, FT-IR, and DSC analysis. Furthermore, the role of the PdLn@Et-β-CD fragment in the reaction mechanism studied by molecular complexation was proposed based on FT-IR, 2D NMR (ROESY) spectroscopy, FE-SEM, and DSC spectroscopic analysis. The important benefits of this technique comprise simple phosphine-free preparation of the palladium catalyst, a wide range of functional-group tolerance, and easy recyclability; this method, furthermore, eschews hazardous reagents or solvents.

Comparison of antinociceptive effects of plain lidocaine versus lidocaine complexed with hydroxypropyl-β-cyclodextrin in animal models of acute and persistent orofacial pain

Herein, it was investigated whether a complex of lidocaine with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) would present a better antinociceptive profile in vivo when compared with plain lidocaine in models of orofacial pain. Plain lidocaine (LDC) and complexed lidocaine (LDC:HP-β-CD) were initially evaluated in vitro to determine the release rate of the two formulations. Subsequently, the effect of both formulations was evaluated in independent groups of rats submitted to the orofacial formalin test, induction of facial heat hyperalgesia by capsaicin and carrageenan, and induction of facial heat and mechanical hyperalgesia by constriction of the infraorbital nerve. LDC:HP-β-CD led to a reduction in the lidocaine release assessed in the in vitro release assay compared to plain LDC. Both formulations presented an antinociceptive effect in all models, but LDC:HP-β-CD showed a better effect in the second phase of the formalin response, in carrageenan-induced heat hyperalgesia, and in the heat hyperalgesia associated to infraorbital nerve constriction. Our results show that complexation improved in vivo antinociceptive effects of LDC, but further studies are necessary to elucidate what properties contribute to the better effect of the complexed formulation on this models and/or what characteristics of the pain model facilitate the action of the complexed formulation.

Cyclodextrin complexes: Perspective from drug delivery and formulation

Cyclodextrins (CDs) have been widely investigated as a unique pharmaceutical excipient for past few decades and is still explored for new applications. They are highly versatile oligosaccharides which possess multifunctional characteristics, and are mainly used to improve the physicochemical stability, solubility, dissolution rate, and bioavailability of drugs. Stability constant, factors affecting complexation, techniques to enhance complexation efficiency, the preparation methods for molecular inclusion complexes and release of guest molecules are discussed in brief. In addition, different CD derivatives and their pharmacokinetics are elaborated. Further, the significance of CD complex in aqueous solubility, dissolution and bioavailability, stability, and taste masking is explained. The recent advancement of CDs in developing various drug delivery systems is enlightened. Indeed, the potential of CDs by means of inclusion complex formation have widen the applicability of these materials in various drug delivery systems including ocular, osmotic, mucoadhesive, transdermal, nasal, and targeted delivery systems. Feasibility studies have been performed on the benefit of these cyclic oligomers as nanocarriers, a strategy that can modify the drugs with improved physicochemical properties. Studies also demonstrated the feasibility of CDs to self-assemble in the form of stable nanoaggregates, which may extend the scope of CDs in drug delivery to the continually expanding list of new drug entities.

Effects of lidocaine and the inclusion complex with 2-hydroxypropyl-β-cyclodextrin on cell viability and proliferation of oral squamous cell carcinoma

OBJECTIVES

Squamous cell carcinoma (SCC) is a malignant disease that affects the oral cavity. Lidocaine has shown antiproliferative and cytotoxic activity on several cell types. The rapid dispersion is a limitation issue; however, the complexation in cyclodextrin improved pharmacological features and modified the drug release. This study investigated the effects of lidocaine (lido) complexed with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD-lido) on cell viability and proliferation of human tongue squamous cell carcinoma SCC9 and SCC25.

METHODS

The complex formation was confirmed by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Cells SCC9 and SCC25 were exposed to lido and HP-β-CD-lido (40-4000 μm), and the effects on cell viability (MTT) and antiproliferative activity (SRB) were tested.

KEY FINDINGS

Differential scanning calorimetry and SEM results demonstrated the occurrence of host-guest interaction. Lido and HP-β-CD-lido (4000 μm) significantly reduced the viability of SCC9 cells to 83% and 63%, respectively. The viability of SCC25 treated with lido, and HP-β-CD-lido (4000 μm) was 71% and 44%, respectively. Lido (4000 μm) reduced the proliferation of SCC9 and SCC25 to 39.5% and 23.7%, respectively. HP-β-CD-lido (4000 μm) was cytotoxic for both cell lines.

CONCLUSIONS

HP-β-CD was able to potentiate the in vitro cytotoxic effects of lidocaine on human squamous cell carcinoma.

Enhanced Solubilization of Fluoranthene by Hydroxypropyl β-Cyclodextrin Oligomer for Bioremediation

Fluoranthene (FT) is a polycyclic aromatic hydrocarbon (PAH), consisting of naphthalene and benzene rings connected by a five-member ring. It is widespread in the environment. The hydrophobicity of FT limits its availability for biological uptake and degradation. In this study, hydroxypropyl β-cyclodextrin oligomers (HP-β-CD-ol) were synthesized with epichlorohydrin (EP), while the solubility enhancement of FT by HP-β-CD-ol was investigated in water. The synthesized HP-β-CD-ol was characterized by MALDI-TOF mass spectrometry (MS), ¹H NMR, and 13C NMR spectroscopy. The solubility of FT increased 178-fold due to the complex formation with HP-β-CD oligomers. The inclusion complexes of FT/HP-β-CD-ol were analyzed using Fourier-Transform Infrared (FT-IR), Differential Scanning Calorimetry (DSC), Scanning Electron Microscope (SEM), and Nuclear Overhauser Effect Spectroscopy Nuclear magnetic resonance (NOESY NMR) spectroscopy. On the basis of these results, HP-β-CD-ol is recommended as a potential solubilizer for the development of PAH removal systems.

Inclusion Complexes of Copaiba (Copaifera multijuga Hayne) Oleoresin and Cyclodextrins: Physicochemical Characterization and Anti-Inflammatory Activity

Complexation with cyclodextrins (CDs) is a technique that has been extensively used to increase the aqueous solubility of oils and improve their stability. In addition, this technique has been used to convert oils into solid materials. This work aims to develop inclusion complexes of Copaifera multijuga oleoresin (CMO), which presents anti-inflammatory activity, with β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) by kneading (KND) and slurry (SL) methods. Physicochemical characterization was performed to verify the occurrence of interactions between CMO and the cyclodextrins. Carrageenan-induced hind paw edema in mice was carried out to evaluate the anti-inflammatory activity of CMO alone as well as complexed with CDs. Physicochemical characterization confirmed the formation of inclusion complex of CMO with both β-CD and HP-β-CD by KND and SL methods. Carrageenan-induced paw edema test showed that the anti-inflammatory activity of CMO was maintained after complexation with β-CD and HP-β-CD, where they were able to decrease the levels of nitrite and myeloperoxidase. In conclusion, this study showed that it is possible to produce inclusion complexes of CMO with CDs by KND and SL methods without any change in CMO’s anti-inflammatory activity.

High-Fat Diet Changes Fungal Microbiomes and Interkingdom Relationships in the Murine Gut

Recent research shows that gut microbes are involved in the development of obesity, a growing health problem in developed countries that is linked to increased risk for cardiovascular disease. However, studies showing links between microbes and metabolism have been limited to the analysis of bacteria and have ignored the potential contribution of fungi in metabolic health. This study provides evidence that ingestion of a high-fat diet is associated with changes to the fungal (and bacterial) microbiome in a mouse model. In addition, we find that interkingdom structural and functional relationships exist between fungi and bacteria within the gut and that these are perturbed by high-fat diet.

Dietary fat intake and shifts in gut bacterial community composition are associated with the development of obesity. To date, characterization of microbiota in lean versus obese subjects has been dominated by studies of gut bacteria. Fungi, recently shown to affect gut inflammation, have received little study for their role in obesity. We sought to determine the effects of high-fat diet on fungal and bacterial community structures in a mouse model using the internal transcribed spacer region 2 (ITS2) of fungal ribosomal DNA (rDNA) and the 16S rRNA genes of bacteria. Mice fed a high-fat diet had significantly different abundances of 19 bacterial and 6 fungal taxa than did mice fed standard chow, with high-fat diet causing similar magnitudes of change in overall fungal and bacterial microbiome structures. We observed strong and complex diet-specific coabundance relationships between intra- and interkingdom microbial pairs and dramatic reductions in the number of coabundance correlations in mice fed a high-fat diet compared to those fed standard chow. Furthermore, predicted microbiome functional modules related to metabolism were significantly less abundant in high-fat-diet-fed than in standard-chow-fed mice. These results suggest a role for fungi and interkingdom interactions in the association between gut microbiomes and obesity.

IMPORTANCE Recent research shows that gut microbes are involved in the development of obesity, a growing health problem in developed countries that is linked to increased risk for cardiovascular disease. However, studies showing links between microbes and metabolism have been limited to the analysis of bacteria and have ignored the potential contribution of fungi in metabolic health. This study provides evidence that ingestion of a high-fat diet is associated with changes to the fungal (and bacterial) microbiome in a mouse model. In addition, we find that interkingdom structural and functional relationships exist between fungi and bacteria within the gut and that these are perturbed by high-fat diet.

Raman and Infrared spectroscopies and X-ray diffraction data on bupivacaine and ropivacaine complexed with 2-hydroxypropyl-β-cyclodextrin

The data presented in this article are related to the research article entitled “Probing the dynamics of complexed local anesthetics via neutron scattering spectroscopy and DFT calculations (http://dx.doi.org/10.1016/j.ijpharm.2017.03.051)” (Martins et al., 2017) [1]. This work shows the molecular and structural behavior of the local anesthetics (LAs) bupivacaine (BVC, C₁₈H₂₈N₂O) and ropivacaine (RVC, C₁₇H₂₆N₂O) before and after complexation with the water-soluble oligosaccharide 2-hydroxypropyl−β−cyclodextrin (HP-β-CD).

Probing the dynamics of complexed local anesthetics via neutron scattering spectroscopy and DFT calculations

Since potential changes in the dynamics and mobility of drugs upon complexation for delivery may affect their ultimate efficacy, we have investigated the dynamics of two local anesthetic molecules, bupivacaine (BVC, C₁₈H₂₈N₂O) and ropivacaine (RVC, C₁₇H₂₆N₂O), in both their crystalline forms and complexed with water-soluble oligosaccharide 2-hydroxypropyl-β-cyclodextrin (HP-β-CD). The study was carried out by neutron scattering spectroscopy, along with thermal analysis, and density functional theory computation. Mean square displacements suggest that RVC may be less flexible in crystalline form than BVC, but both molecules exhibit very similar dynamics when confined in HP-β-CD. The use of vibrational analysis by density functional theory (DFT) made possible the identification of molecular modes that are most affected in both molecules by insertion into HP-β-CD, namely those of the piperidine rings and methyl groups. Nonetheless, the somewhat greater structure in the vibrational spectrum at room temperature of complexed RVC than that of BVC, suggests that the effects of complexation are more severe for the latter. This unique approach to the molecular level study of encapsulated drugs should lead to deeper understanding of their mobility and the respective release dynamics.

Drug delivery systems for prolonged duration local anesthesia

Numerous drug delivery systems have been applied to the problem of providing prolonged duration local anesthesia (PDLA). Here we review the rationale for PDLA, the desirable features for and important attributes of such systems, and specific examples that have been developed.

Characterization and In Vitro Evaluation of the Complexes of Posaconazole with β- and 2,6-di-O-methyl-β-cyclodextrin

Posaconazole is a triazole antifungal drug that with extremely poor aqueous solubility. Up to now, this drug can be administered via intravenous injection and oral suspension. However, its oral bioavailability is greatly limited by the dissolution rate of the drug. This study aimed to improve water solubility and dissolution of posaconazole through characterizing the inclusion complexes of posaconazole with β-cyclodextrin (β-CD) and 2,6-di-O-methyl-β-cyclodextrin (DM-β-CD). Phase solubility studies were performed to calculate the stability constants in solution. The results of FT-IR, PXRD, ¹H and ROESY 2D NMR, and DSC all verified the formation of the complexes in solid state. The complexes showed remarkably improved water solubility and dissolution rate than pure posaconazole. Especially, the aqueous solubility of the DM-β-CD complex is nine times higher than that of the β-CD complex. Preliminary in vitro antifungal susceptibility tests showed that the two inclusion complexes maintained high antifungal activities. These results indicated that the DM-β-CD complexes have great potential for application in the delivery of poorly water-soluble antifungal agents, such as posaconazole.

The effect of two drug delivery systems in ropivacaine cytotoxicity and cytokine release by human keratinocytes and fibroblasts

Objectives

Modified drug delivery systems have been developed to improve pharmacological properties of local anaesthetics. However, the inflammatory potential of these formulations was not investigated. This study compared the in-vitro effects of ropivacaine (ropi) in plain, liposomal (MLV) or 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) formulations on cell viability, apoptosis and cytokine (IL-1α, TNF-α, IL-6 and IL-10) release.

Methods

Human immortalized keratinocytes (HaCaT) and human immortalized gingival fibroblasts (HGF) were exposed to 1–100 μm ropi concentrations. The cell viability was measured by XTT and LIVE/DEAD assay. Apoptosis was performed by flow cytometry, and cytokine release was measured by ELISA assay.

Key findings

Human immortalized keratinocyte viability was reduced by ropi and both drug delivery systems. However, none of the formulations induced apoptosis. Results showed a differential regulation of IL-1α TNF-α, IL-6 and IL-10 by HaCaT and HGF. Ropi-HP-β-CD increased twofold the IL-6 release by HGF in comparison with the control, while 100 μm ropi-MLV led to an increased release of all pro-inflammatory cytokines by HGF.

Conclusion

The loss in cell viability was not related to cellular apoptosis. Ropi complexed with HP-β-CD showed a similar cytokine release pattern when compared to the plain formulation. Thus, the HP-β-CD form was a better drug carrier than the MLV form for ropivacaine drug delivery.