Cyclodextrins, blood-brain barrier, and treatment of neurological diseases

Interactions of a Novel Anthracycline with Oligonucleotide DNA and Cyclodextrins in an Aqueous Environment

Berubicin, a chemotherapy medication belonging to the class of anthracyclines, is simulated in double-stranded DNA sequences and cyclodextrins in an aqueous environment via full-atom molecular dynamics simulations on the time scale of microseconds. The drug is studied in both the neutral and protonated states so as to better comprehend the role of its charge in the formed complexes. The noncovalent berubicin-DNA and berubicin-cyclodextrin complexes are investigated in detail, paying special attention to their thermodynamic description by employing the double decoupling method, the solvent balance method, the weighted solvent accessible surface model, and the linear interaction energy method. A novel approach for extracting the desolvation thermodynamics of the binding process is also presented. Both the binding and desolvation Gibbs energies are decomposed into entropic and enthalpic contributions so as to elucidate the nature of complexation and its driving forces. Selected structural and geometrical properties of all the complexes, which are all stable, are analyzed. Both cyclodextrins under consideration are widely utilized for drug delivery purposes, and a comparative investigation between their bound states with berubicin is carried out.

Integrated multi-omics profiling highlights the benefits of resveratrol hydroxypropyl-β-cyclodextrin inclusion complex for A53T transgenic mice through the microbiota-gut-brain axis

Parkinson's disease (PD) is a neurological disorder characterized by motor and gastrointestinal dysfunctions. Resveratrol is a potent antioxidant and anti-inflammatory phytoalexin known for its health-promoting benefits. However, little is known about its potential in treating PD by modulating the microbial gut-brain axis, and its clinical application has been limited due to poor water solubility, rapid metabolism, and limited systemic bioavailability. Our study aimed to evaluate the therapeutic potential of RHSD, a resveratrol-cyclodextrin inclusion complex, in treating PD through the gut-brain axis in human SNCA-transgenic (A53T) mice PD models. Building on our previous study, we prepared RHSD and compared its efficacy with uncoated resveratrol for PD treatment. The study results demonstrated that RHSD exhibited several advantages in improving motor function, alleviating cognitive impairment, restoring intestinal barrier function, and inhibiting neuropathy. Subsequently, a series of analyses, including fecal microbiota metagenomic sequencing, non-target metabolic assays, host transcriptome sequencing, and integrative analysis were performed to reveal the potential therapeutic pathways of RHSD in A53T mice. The metagenomic sequencing results indicated a significant increase in the levels of Lactobacillus murinus, Lactobacillus reuteri, Enterorhabduscaecimuris, Lactobacillus taiwanensis, and Lactobacillus animals following RHSD administration. Furthermore, metabolomics profiling showed that the levels of gut microbiome metabolites were reversed after RHSD treatment, and differential metabolites were significantly correlated with motor function and intestinal function in PD mice. The integrated analysis of microbial metabolites and host transcriptomics suggested that abnormal amino acid metabolism, mitochondrial dysfunction, oxidative stress, and neuroinflammation in the PD model were associated with the diffusion of abnormal metabolites. This study illustrates the profound impact of RHSD administration on rectifying gut microbiota dysbiosis and improving the A53T mouse model. Notably, we observed significant alterations in the proliferation and metabolism of multiple probiotic strains of Lactobacillus. Furthermore, our research supports the hypothesis that microbiota-related metabolites may regulate the transcription of host genes, including dopamine receptors and calcium stabilization. Consequently, our findings underscore the potential of RHSD as a promising therapeutic candidate for the treatment of PD through the modulation of several signaling pathways within the microbiota-gut-brain axis.

Access to the CNS: Strategies to overcome the BBB

The blood-brain barrier (BBB) limits the access of substances to the central nervous system (CNS) which hinders the treatment of pathologies affecting the brain and the spinal cord. Nowadays, research is focus on new strategies to overcome the BBB and can treat the pathologies affecting the CNS are needed. In this review, the different strategies that allow and increase the access of substances to the CNS are analysed and extended commented, not only invasive strategies but also non-invasive ones. The invasive techniques include the direct injection into the brain parenchyma or the CSF and the therapeutic opening of the BBB, while the non-invasive techniques include the use of alternative routes of administration (nose-to-brain route), the inhibition of efflux transporters (as it is important to prevent the drug efflux from the brain and enhance the therapeutic efficiency), the chemical modification of the molecules (prodrugs and chemical drug delivery systems (CDDS)) and the use of nanocarriers. In the future, knowledge about nanocarriers to treat CNS diseases will continue to increase, but the use of other strategies such as drug repurposing or drug reprofiling, which are cheaper and less time consuming, may limit its transfer to society. The main conclusion is that the combination of different strategies may be the most interesting approach to increase the access of substances to the CNS.

Cyclodextrin-Based Nanoparticles for Delivery of Antisense Oligonucleotides Targeting Huntingtin

Huntington's disease (HD) is a progressive inherited neurodegenerative disease caused by a CAG repeat expansion in the huntingtin gene, which is translated into the pathologic mutant huntingtin (mHTT) protein. Despite the great potential of HTT lowering strategies and the numerous antisense oligonucleotides (ASOs) in pre- and clinical trials, sustained silencing of mHTT has not been achieved. As a strategy to improve ASO delivery, cyclodextrin-based nanoparticles (CDs) offer a promising approach. Here, three CDs with distinct chemical structures were designed and their efficacies were compared as potential platforms for the delivery of ASO targeting HTT. Results using striatal neurons and HD patient-derived fibroblasts indicate that modified γ-CDs exhibited the best uptake efficiency and successfully downregulated mHTT at protein and allele levels. The incorporation of the brain-targeting peptide RVG into the modified γ-CDs showed greater downregulation of mHTT protein and HD-causing allele SNP1 than untargeted ones in an in vitro blood-brain barrier model. Although the ASO sequence was designed as a nonallele-specific therapeutic approach, our strategy gives an additional benefit of some mHTT selectivity. Overall, this study demonstrated the CD platform's feasibility for delivering ASO-based therapeutics for HD treatment.

Cyclodextrins applied to the treatment of lysosomal storage disorders

Cyclodextrin (CD), a cyclic oligosaccharide, is a pharmaceutical additive that improves the solubility of hydrophobic compounds. Recent research has focused on the potential active pharmaceutical abilities of CD. Lysosomal storage diseases are inherited metabolic diseases characterized by lysosomal dysfunction and abnormal lipid storage. Niemann-Pick disease type C (NPC) is caused by mutations in cholesterol transporter genes (NPC1, NPC2) and is characterized by cholesterol accumulation in lysosomes. A biocompatible cholesterol solubilizer 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) was recently used in NPC patients for compassionate use and in clinical trials. HP-β-CD is an attractive drug candidate for NPC; however, its adverse effects, such as ototoxicity, should be solved. In this review, we discuss the current use of HP-β-CD in basic and clinical research and discuss alternative CD derivatives that may outperform HP-β-CD, which should be considered for clinical use. The potential of CD therapy for the treatment of other lysosomal storage diseases is also discussed.

Effects of Hydroxypropyl-Beta-Cyclodextrin on Cultured Brain Endothelial Cells

The application of 2-hydroxypropyl-beta-cyclodextrin (HPBCD) in the treatment of the rare cholesterol and lipid storage disorder Niemann-Pick disease type C opened new perspectives in the development of an efficient therapy. Even if the systemic administration of HPBCD was found to be effective, its low permeability across the blood-brain barrier (BBB) limited the positive neurological effects. Nevertheless, the cellular interactions of HPBCD with brain capillary endothelial cells have not been investigated in detail. In this study, the cytotoxicity, permeability, and cellular internalization of HPBCD on primary rat and immortalized human (hCMEC/D3) brain capillary endothelial cells were investigated. HPBCD shows no cytotoxicity on endothelial cells up to 100 µM, measured by impedance kinetics. Using a fluorescent derivative of HPBCD (FITC-HPBCD) the permeability measurements reveal that on an in vitro triple co-culture BBB model, FITC-HPBCD has low permeability, 0.50 × 10^-6 cm/s, while on hCMEC/D3 cell layers, the permeability is higher, 1.86 × 10^-5 cm/s. FITC-HPBCD enters brain capillary endothelial cells, is detected in cytoplasmic vesicles and rarely localized in lysosomes. The cellular internalization of HPBCD at the BBB can help to develop new strategies for improved HPBCD effects after systemic administration.

Implementation of Water-Soluble Cyclodextrin-Based Polymers in Biomedical Applications: How Far are we?

Cyclodextrin-based polymers can be prepared starting from the naturally occurring monomers following green and low-cost procedures. They can be selectively derivatized pre- or post-polymerization allowing to fine-tune functionalities of ad hoc customized polymers. Preparation nowadays has reached the 100 g scale thanks also to the interest of industries in these extremely versatile compounds. During the last 15 years these macromolecules have been the object of intense investigations in view of possible biomedical applications as the ultimate goal and large amounts of scientific data are now available. Compared to their monomeric models, already used in the formulation of various therapeutic agents, they display superior behavior in terms of their solubility in water and solubilizing power towards drugs incompatible with biological fluids. Moreover, they allow the combination of more than one type of therapeutic agent in the polymeric system. In this review we provide a complete state-of-the-art on the knowledge and potentialities of water-soluble cyclodextrin-based polymers as therapeutic agents as well as carrier systems for different types of therapeutics to implement combination therapy. Finally, we give a perspective on their assets for innovation in disease treatment as well as their limits that still need to be addressed. This article is protected by copyright. All rights reserved.

Cellular Effects of Cyclodextrins: Studies on HeLa Cells

Cyclodextrins are high molecular weight, hydrophilic, cyclic, non-reducing oligosaccharides, applied as excipients for the improvement of the solubility and permeability of insoluble active pharmaceutical ingredients. On the other hand, beta-cyclodextrins are used as cholesterol sequestering agents in life sciences. Recently, we demonstrated the cellular internalization and intracellular effects of cyclodextrins on Caco-2 cells. In this study, we aimed to further investigate the endocytosis of (2-hydroxylpropyl)-beta-(HPBCD) and random methylated-beta-cyclodextrin (RAMEB) to test their cytotoxicity, NF-kappa B pathway induction, autophagy, and lysosome formation on HeLa cells. These derivatives were able to enter the cells; however, major differences were revealed in the inhibition of their endocytosis compared to Caco-2 cells. NF-kappa B p65 translocation was not detected in the cell nuclei after HPBCD or RAMEB pre-treatment and cyclodextrin treatment did not enhance the formation of autophagosomes. These cyclodextrin derivates were partially localized in lysosomes after internalization.

The Biological Fate of Pharmaceutical Excipient β-Cyclodextrin: Pharmacokinetics, Tissue Distribution, Excretion, and Metabolism of β-Cyclodextrin in Rats

β-cyclodextrin has a unique annular hollow ultrastructure that allows encapsulation of various poorly water-soluble drugs in the resulting cavity, thereby increasing drug stability. As a bioactive molecule, the metabolism of β-cyclodextrin is mainly completed by the flora in the colon, which can interact with API. In this study, understanding the in vivo fate of β-cyclodextrin, a LC-MS/MS method was developed to facilitate simultaneous quantitative analysis of pharmaceutical excipient β-cyclodextrin and API dextromethorphan hydrobromide. The established method had been effectively used to study the pharmacokinetics, tissue distribution, excretion, and metabolism of β-cyclodextrin after oral administration in rats. Results showed that β-cyclodextrin was almost wholly removed from rat plasma within 36 h, and high concentrations of β-cyclodextrin distributed hastily to organs with increased blood flow velocities such as the spleen, liver, and kidney after administration. The excretion of intact β-cyclodextrin to urine and feces was lower than the administration dose. It can be speculated that β-cyclodextrin metabolized to maltodextrin, which was further metabolized, absorbed, and eventually discharged in the form of CO₂ and H₂O. Results proved that β-cyclodextrin, with relative low accumulation in the body, had good safety. The results will assist further study of the design and safety evaluation of adjuvant β-cyclodextrin and promote its clinical development.

The bee venom active compound melittin protects against bicuculline-induced seizures and hippocampal astrocyte activation in rats

Epilepsy is a chronic neuropathology characterized by an abnormal hyperactivity of neurons that generate recurrent, spontaneous, paradoxical and synchronized nerve impulses, leading or not to seizures. This neurological disorder affects around 70 million individuals worldwide. Pharmacoresistance is observed in about 30% of the patients and long-term use of antiepileptics may induce serious side effects. Thus, there is an interest in the study of the therapeutic potential of bioactive substances isolated from natural products in the treatment of epilepsy. Arthropod venoms contain neurotoxins that have high affinity for molecular structures in the neural tissue such as receptors, transporters and ion channels both in glial and neuronal membranes. This study evaluated the potential neuroprotective effect of melittin (MEL), an active compound of bee venom, in the bicuculline-induced seizure model (BIC) in rats. Male Wistar rats (3 months, 250-300 g) were submitted to surgery for the implantation of a unilateral cannula in the lateral ventricle. After the recovery period, rats received a microinjection of saline solution or MEL (0.1 mg per animal). Firstly, rats were evaluated in the open field (20 min) and in the elevated plus maze (5 min) tests after received microinjection of saline or MEL. After, 30 min later animals received BIC (100 mg/ml) or saline, and their behaviors were analyzed for 20 min in the open field according to a seizure scale. At the end, rats were euthanized, brains collected and processed to glial fibrillary acidic protein (GFAP) immunohistochemistry evaluation. No changes were observed in MEL-treated rats in the open field and elevated plus maze. However, 90% of MEL-treated animals were protected against seizures induced by BIC. There was an increase in the latency for the onset of seizures, accompanied by a reduction of GFAP-immunoreactivity cells in the dentate gyrus and CA1. Thus, our study suggests that MEL has an anticonvulsant potential, and further studies are needed to elucidate the mechanisms involved in this action.

Review of Current Strategies for Delivering Alzheimer's Disease Drugs Across the Blood-Brain Barrier

(Appeared originally in the International Journal of Molecular Sciences 2019; 20:381) Reprinted under Creative Commons CC-BY license.

Sterols lower energetic barriers of membrane bending and fission necessary for efficient clathrin-mediated endocytosis

Clathrin-mediated endocytosis (CME) is critical for cellular signal transduction, receptor recycling, and membrane homeostasis in mammalian cells. Acute depletion of cholesterol disrupts CME, motivating analysis of CME dynamics in the context of human disorders of cholesterol metabolism. We report that inhibition of post-squalene cholesterol biosynthesis impairs CME. Imaging of membrane bending dynamics and the CME pit ultrastructure reveals prolonged clathrin pit lifetimes and shallow clathrin-coated structures, suggesting progressive impairment of curvature generation correlates with diminishing sterol abundance. Sterol structural requirements for efficient CME include 3′ polar head group and B-ring conformation, resembling the sterol structural prerequisites for tight lipid packing and polarity. Furthermore, Smith-Lemli-Opitz fibroblasts with low cholesterol abundance exhibit deficits in CME-mediated transferrin internalization. We conclude that sterols lower the energetic costs of membrane bending during pit formation and vesicular scission during CME and suggest that reduced CME activity may contribute to cellular phenotypes observed within disorders of cholesterol metabolism.

Anderson et al. demonstrate that sterol abundance and identity play a dominant role in facilitating clathrin-mediated endocytosis. Detailed analyses of clathrin-coated pits under sterol depletion support a requirement for sterol-mediated membrane bending during multiple stages of endocytosis, implicating endocytic dysfunction within the pathogenesis of disorders of cholesterol metabolism.

M01 as a novel drug enhancer for specifically targeting the blood-brain barrier

Drug delivery to the brain is limited for most pharmaceuticals by the blood-brain barrier (BBB) where claudin-5 dominates the paraendothelial tightening. For circumventing the BBB, we identified the compound M01 as a claudin-5 interaction inhibitor. M01 causes transient permeabilisation of the BBB depending on the concentration of small molecules in different cell culture models within 3 to 48 h. In mice, brain uptake of fluorescein peaked within the first 3 h after M01 injection and normalised within 48 h. Compared to the cytostatic paclitaxel alone, M01 improved delivery of paclitaxel to mouse brain and reduced orthotopic glioblastoma growth. Results on interactions of M01 with claudin-5 were incorporated into a binding model which suggests association of its aromatic parts with highly conserved residues of the extracellular domain of claudin-5 and adjacent transmembrane segments. Our results indicate the following mode of action: M01 preferentially binds to the extracellular claudin-5 domain, which weakens trans-interactions between adhering cells. Further decrease in membranous claudin-5 levels due to internalization and transcriptional downregulation enables the paracellular passage of small molecules. In summary, the first small molecule is introduced here as a drug enhancer, which specifically permeabilises the BBB for a sufficient interval for allowing neuropharmaceuticals to enter the brain.

Myrtenol complexed with β-cyclodextrin ameliorates behavioural deficits and reduces oxidative stress in the reserpine-induced animal model of Parkinsonism

Current pharmacological approaches to treat Parkinson's disease have low long-term efficacy and important adverse side effects. The development of new pharmacological therapies has focused on novel plant-derived phytochemicals. The alcoholic monoterpene myrtenol has been isolated from several plant species, and has anxiolytic, analgesic, anti-inflammatory and antioxidant actions. Our study evaluated the neuroprotective potential of myrtenol complexed with β-cyclodextrin (MYR) on a progressive parkinsonism model induced by reserpine (RES) in mice. The complexation with cyclodextrins enhances the pharmacological action of monoterpenes. Male Swiss mice were treated daily with MYR (5 mg/kg, p.o.) and with RES (0.1 mg/kg, s.c.) every other day during 28 days. Behavioural evaluations were conducted across treatment. At the end of the treatment, immunohistochemistry for tyrosine hydroxylase (TH) and oxidative stress parameters were evaluated. Chronic MYR-treatment protected against olfactory sensibility loss, restored short-term memory and decreased RES-induced motor impairments. Moreover, this treatment prevented dopaminergic depletion and reduced the oxidative status index in the dorsal striatum. Therefore, MYR ameliorated motor and non-motor impairments in the progressive animal model of parkinsonism, possibly by an antioxidant action. Additional research is needed to investigate the mechanisms involved in this neuroprotective effect.

Force Field Parameterization for the Description of the Interactions between Hydroxypropyl-β-Cyclodextrin and Proteins

Cyclodextrins are cyclic oligosaccharides, widely used as drug carriers, solubilizers, and excipients. Among cyclodextrins, the functionalized derivative known as hydroxypropyl-β-cyclodextrin (HPβCD) offers several advantages due to its unique structural features. Its optimal use in pharmaceutical and medical applications would benefit from a molecular-level understanding of its behavior, as can be offered by molecular dynamics simulations. Here, we propose a set of parameters for all-atom simulations of HPβCD, based on the ADD force field for sugars developed in our group, and compare it to the original CHARMM36 description. Using Kirkwood-Buff integrals of binary HPβCD-water mixtures as target experimental data, we show that the ADD-based description results in a considerably improved prediction of HPβCD self-association and interaction with water. We then use the new set of parameters to characterize the behavior of HPβCD toward the different amino acids. We observe pronounced interactions of HPβCD with both polar and nonpolar moieties, with a special preference for the aromatic rings of tyrosine, phenylalanine, and tryptophan. Interestingly, our simulations further highlight a preferential orientation of HPβCD's hydrophobic cavity toward the backbone atoms of amino acids, which, coupled with a favorable interaction of HPβCD with the peptide backbone, suggest a propensity for HPβCD to denature proteins.

Spatiotemporal Developmental Upregulation of Prestin Correlates With the Severity and Location of Cyclodextrin-Induced Outer Hair Cell Loss and Hearing Loss

2-Hyroxypropyl-beta-cyclodextrin (HPβCD) is being used to treat Niemann-Pick C1, a fatal neurodegenerative disease caused by abnormal cholesterol metabolism. HPβCD slows disease progression, but unfortunately causes severe, rapid onset hearing loss by destroying the outer hair cells (OHC). HPβCD-induced damage is believed to be related to the expression of prestin in OHCs. Because prestin is postnatally upregulated from the cochlear base toward the apex, we hypothesized that HPβCD ototoxicity would spread from the high-frequency base toward the low-frequency apex of the cochlea. Consistent with this hypothesis, cochlear hearing impairments and OHC loss rapidly spread from the high-frequency base toward the low-frequency apex of the cochlea when HPβCD administration shifted from postnatal day 3 (P3) to P28. HPβCD-induced histopathologies were initially confined to the OHCs, but between 4- and 6-weeks post-treatment, there was an unexpected, rapid and massive expansion of the lesion to include most inner hair cells (IHC), pillar cells (PC), peripheral auditory nerve fibers, and spiral ganglion neurons at location where OHCs were missing. The magnitude and spatial extent of HPβCD-induced OHC death was tightly correlated with the postnatal day when HPβCD was administered which coincided with the spatiotemporal upregulation of prestin in OHCs. A second, massive wave of degeneration involving IHCs, PC, auditory nerve fibers and spiral ganglion neurons abruptly emerged 4–6 weeks post-HPβCD treatment. This secondary wave of degeneration combined with the initial OHC loss results in a profound, irreversible hearing loss.

Natural polymeric nanocarriers in malignant glioma drug delivery and targeting

Among all central nervous diseases, malignant glioma is a crucial part that deserves more attention since high fatality and disability rate. There are several therapeutic strategies applied to the treatment of malignant glioma, especially certain chemotherapy-related treatments. However, the existence of the blood-brain barrier (BBB) seriously hinders the strategy's progress, so how to escape from the barriers is a fascinating question. Herein, we comprehensively discussed the details of malignant glioma and the BBB's functional morphology and summarized several routes bypassing the BBB. Additionally, since possessing excellent properties for drug delivery, we provided an insight into various promising natural polymeric materials and highlighted their applications in the treatment of malignant glioma.

Cytotoxicity of β-Cyclodextrins in Retinal Explants for Intravitreal Drug Formulations

Cyclodextrins (CDs) have been widely used as pharmaceutical excipients for formulation purposes for different delivery systems. Recent studies have shown that CDs are able to form complexes with a variety of biomolecules, such as cholesterol. This has subsequently paved the way for the possibility of using CDs as drugs in certain retinal diseases, such as Stargardt disease and retinal artery occlusion, where CDs could absorb cholesterol lumps. However, studies on the retinal toxicity of CDs are limited. The purpose of this study was to examine the retinal toxicity of different beta-(β)CD derivatives and their localization within retinal tissues. To this end, we performed cytotoxicity studies with two different CDs—2-hydroxypropyl-βCD (HPβCD) and randomly methylated β-cyclodextrin (RMβCD)—using wild-type mouse retinal explants, the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and fluorescence microscopy. RMβCD was found to be more toxic to retinal explants when compared to HPβCD, which the retina can safely tolerate at levels as high as 10 mM. Additionally, studies conducted with fluorescent forms of the same CDs showed that both CDs can penetrate deep into the inner nuclear layer of the retina, with some uptake by Müller cells. These results suggest that HPβCD is a safer option than RMβCD for retinal drug delivery and may advance the use of CDs in the development of drugs designed for intravitreal administration.

Drug delivery and targeting to brain tumors: considerations for crossing the blood-brain barrier

Introduction: The blood-brain barrier (BBB) selectively impedes the transportation of drug molecules into the brain, which makes the drug delivery and targeting of brain tumors very challenging.Areas covered: Having surveyed the recent literature, comprehensive insights are given into the impacts of the BBB on the advanced drug delivery and targeting modalities for brain tumors.Expert opinion: Brain capillary endothelial cells form the BBB in association with astrocytes, pericytes, neurons, and extracellular matrix. Coop of these forms the complex setting of neurovascular unite. The BBB maintains the brain homeostasis by restrictive controlling of the blood circulating nutrients/substances trafficking. Despite substantial progress on therapy of brain tumors, there is no impeccable strategy to safely deliver chemotherapeutics into the brain. Various strategies have been applied to deliver chemotherapeutics into the brain (e.g. BBB opening, direct delivery by infusion, injection, microdialysis, and implants, and smart nanosystems), which hold different pros and cons. Of note, smart nanoscale multifunctional nanomedicines can serve as targeting, imaging, and treatment modality for brain tumors. Given that aggressive brain tumors (e.g. gliomas) are often unresponsive to any treatments, an in-depth understanding of the molecular/cellular complexity of brain tumors might help the development of smart and effective treatment modalities.

Energetic and thermodynamical aspects of the cyclodextrins-cannabidiol complex in aqueous solution: a molecular-dynamics study

Cyclodextrins (CDs) are well-known carriers for encapsulating hydrophobic molecules, while among cannabinoids, cannabidiol (CBD) has attracted considerable attention due to its therapeutic capability. In this framework, we employed molecular dynamics and docking techniques for investigating the interaction energy and thermodynamical issues between different CDs (α, β, and γ type) and CBD immersed in water and a solution mimicking a physiological environment. We quantified the energetic aspects, for different thermal conditions, in which both aqueous solutions interact with CBDs and CDs and the CBD-CDs complex itself. In order to approximate the physiological conditions, our simulations also included the mammalian temperature. The calculations revealed significant interaction energy between lactate and the CD surface and a movement of lactate toward CD as well. We observed an almost constant number of lactate molecules forming clusters without exhibiting a temperature dependence. Next, the degree of CBD-CDs complexation at four different temperatures was analyzed. The results showed that the complexation depends on the medium, becoming weaker with the temperature increment. Our findings highlighted that the entropy contribution is relevant for CBD-α-CD and CBD-β-CD, while CBD-γ-CD is practically insensitive to temperature changes for both solutions. In both water and artificial physiological solutions, the γ-CD appears more stable than the other complexes. Overall, CBD achieved partial encapsulation considering α-CD and β-CD, showing a temperature dependence, while γ-CD remained fully immersed no matter the thermal level assumed. We also discuss the pharmacological relevance and physiological implications of these findings.

Investigation of Cytotoxicity and Cell Uptake of Cationic Beta-Cyclodextrins as Valid Tools in Nasal Delivery

Cyclodextrin polymers have high applicability in pharmaceutical formulations due to better biocompatibility, solubility enhancement, loading capacity and controlled drug release than their parent, cyclodextrins. The cytotoxicity and cell uptake of new cationic beta-cyclodextrin monomers and polymers were evaluated as suitable materials for nasal formulations and their protective effects on cells exposed to hydrogen peroxide were studied. PC12 and CACO-2 cells were selected as the neuronal- and epithelial-type cells, respectively, to mimic the structure of respiratory and olfactory epithelia of the nasal cavity. All cationic beta-cyclodextrin polymers tested showed dose- and time-dependent toxicity; nevertheless, at 5 µM concentration and 60 min of exposure, the quaternary-ammonium-beta-cyclodextrin soluble polymer could be recognized as nontoxic. Based on these results, a fluorescently labelled quaternary-ammonium-beta-cyclodextrin monomer and polymer were selected for uptake studies in CACO-2 cells. The monomeric and polymeric beta-cyclodextrins were internalized in the cytoplasm of CACO-2 cells; the cationic monomer showed higher permeability than the hydroxypropyl-beta-cyclodextrin, employed as comparison. Therefore, these cationic beta-cyclodextrins showed potential as excipients able to improve the nasal absorption of drugs. Furthermore, amino-beta-cyclodextrin and beta-cyclodextrin soluble polymers were able to reduce oxidative damage in PC12 and CACO-2 cells and thus could be studied as bioactive carriers or potential drugs for cell protection against oxidative stress.

Voltammetric/UV-Vis study of temozolomide inclusion complexes with cyclodextrin derivatives

Temozolomide (TMZ) - a chemotherapeutic agent possessing cytotoxic activity is used in single or combined therapies of human glioma. Difficulties in these applications, connected with low solubility and stability of temozolomide lead us to study the inclusion complexes between TMZ, and three cyclodextrins: β-cyclodextrin (βCD), monodeoxy-6-monoamino-β-cyclodextrin hydrochloride (βCDamine), and β-cyclodextrin containing galactosamine and triazole ring in the side group (βCDgal). The voltammetric and spectroscopy studies showed the improvement of the drug solubility and formation of stable complexes. Higuchi and Connors method was used to determine the solubilities of the drug in the presence of the selected cyclodextrins. Phase solubility diagrams showed increase of TMZ solubility and 1:1 stoichiometry of the complexes formed. The stability constant of TMZ- βCDgal complex was pH - dependent, larger at pH 7.4 (corresponding to the pH of the body fluids), than at pH 5.5, characteristic for the cancer cells environment. βCDgal ligand was an effective complexing agent for TMZ due to additional strong proton-acceptor π-π interactions between the triazole ring of the cyclodextrin and the ring of TMZ. The increased solubility and sustainability of TMZ complexes with βCDgal allow to propose this cyclodextrin as a promising TMZ carrier for further studies in the biological cell environment.

Quantifying the hygroscopic properties of cyclodextrin containing aerosol for drug delivery to the lungs

Aerosol dynamics is important to quantify in drug delivery to the lungs with the aim of delivering therapeutics to a target location and optimising drug efficacy. The macrocycle (2-hydroxypropyl)-β-cyclodextrin (2-HP-β-CD) is thought to alleviate symptoms associated with neurodegenerative diseases when inhaled but the hygroscopic response is not well understood. Here we measure the hygroscopic growth of individual aqueous aerosol containing 2-HP-β-CD in optical tweezers through analysis of morphology-dependent resonances arising in Raman spectra. Droplets are analysed in the size range of 3-5 μm in radius. The evolving radius and refractive index of each droplet are measured in response to change in relative humidity from 98-20% to determine mass and radius based hygroscopic growth factors, and compared with dynamic vapour sorption measurements. Bulk solution refractive index and density measurements were used in accordance with the self-consistent Lorenz-Lorentz rule to determine melt solute and droplet properties. The refractive index of 2-HP-β-CD was determined to be 1.520 ± 0.002 with a density of 1.389 ± 0.005 g cm^-3. To our knowledge, we show the first aerosol measurements of 2-HP-β-CD and determine hygroscopicity. By quantifying the hygroscopic growth and physicochemical properties of 2-HP-β-CD, the impact of aerosol dynamics can be accounted for in tailoring drug formulations and informing models used to predict drug deposition patterns within the respiratory system.

Impact of pH and cell medium on the interaction of doxorubicin with lipoic acid cyclodextrin conjugate as the drug carrier

Lipoic acid derivative of cyclodextrin, βCDLip, was used as the drug carrier for doxorubicin (DOX) and the stability constants of the DOX–βCDLip were determined in the environment of the cell medium. The experiments were performed in neutral (pH 7.6) and acidified (pH 6.3) cell media containing more than forty interferences including: amino acids, vitamins, lipids and proteins. We proved that the pH of the medium has a noticeable impact on the affinity of the drug towards the carrier. At neutral pH, the formation constants of the complex are higher than at pH 6.3, what is characteristic for the cancer cells microenvironment. Furthermore, the values obtained in both cell media are twice smaller than the values obtained previously for the same complex but in the absence of common cell media components indicating that there is a competition between DOX and some hydrophobic medium components for the complex formation with βCDLip. On the other hand at pH 7.6, the amount of free DOX is highly limited due to the fact that most of DOX is still in the complexed form, while at pH 6.3 the cell media ingredients become strong interferences in the formation of the complex between DOX and the drug carrier. The observed behaviour is due to partial protonation of DOX and to competition between the drug and the lipoic side arm of cyclodextrin for the cyclodextrin cavity. The stability constants of the DOX–βCDLip complex in acidic pH are similar to the values for DOX with native β-cyclodextrin, demonstrating that the strengthening effect of DOX–CD complex resulting from the presence of cyclodextrin’s aromatic substituent (Lip) occurs only in the case of neutral pH. The high value of the stability constant of the DOX–βCDLip complex in cell medium at pH 7.6 indicates high selectivity of βCDLip ligand which would be of importance both for the effective drug delivery and for its application in DOX sensing devices.

The P2X7 receptor antagonist JNJ-47965567 administered thrice weekly from disease onset does not alter progression of amyotrophic lateral sclerosis in SOD1G93A mice

The ATP-gated P2X7 ion channel has emerging roles in amyotrophic lateral sclerosis (ALS) progression. Pharmacological blockade of P2X7 with Brilliant Blue G can ameliorate disease in SOD1G93A mice, but recent data suggests that this antagonist displays poor penetration of the central nervous system (CNS). Therefore, the current study aimed to determine whether the CNS-penetrant P2X7 antagonist, JNJ-47965567, could ameliorate ALS progression in SOD1G93A mice. A flow cytometric assay revealed that JNJ-47965567 impaired ATP-induced cation dye uptake in a concentration-dependent manner in murine J774 macrophages. Female and male SOD1G93A mice were injected intraperitoneally with JNJ-47965567 (30 mg/kg) or 2-(hydroxypropyl)-beta-cyclodextrin (vehicle control) three times a week from disease onset until end stage, when tissues were collected and studied. JNJ-47965567 did not impact weight loss, clinical score, motor (rotarod) coordination or survival compared to control mice. NanoString analysis revealed altered spinal cord gene expression in JNJ-47965567 mice compared to control mice, but such differences were not confirmed by quantitative PCR. Flow cytometric analyses revealed no differences between treatments in the frequencies or activation status of T cell or dendritic cell subsets in lymphoid tissues or in the concentrations of serum cytokines. Notably, serum IL-27, IFNβ and IL-10 were present in relatively high concentrations compared to other cytokines in both groups. In conclusion, JNJ-47965567 administered thrice weekly from disease onset did not alter disease progression or molecular and cellular parameters in SOD1G93A mice.

Oral and Intra-nasal Administration of Nanoparticles in the Cerebral Ischemia Treatment in Animal Experiments: Considering its Advantages and Disadvantages

BACKGROUND

Over the past few decades, nanotechnology has dramatically advanced; from the precise strategies of synthesizing modern nanostructures to methods of entry into the body. Using nanotechnology in diagnosis, drug delivery, determining signaling pathways, and tissue engineering is great hope for the treatment of stroke. The drug-carrying nanoparticles are a way to increase drug absorption through the mouth or nose in treating the stroke.

OBJECTIVE

In this article, in addition to explaining pros and cons of oral and intra-nasal administration of nanoparticles in the brain ischemia treatment of animal models, the researchers introduce some articles in this field and briefly mentioned their work outcomes.

METHODS

A number of relevant published articles 183 were initially collected from three popular databases including PubMed, Google Scholar, and Scopus. The articles not closely related to the main purpose of the present work were removed from the study process. The present data set finally included 125 published articles.

RESULTS

Direct delivery of the drug to the animal brain through the mouth and nose has more therapeutic effects than systemic delivery of drugs. The strategy of adding drugs to the nanoparticles complex can potentially improve the direct delivery of drugs to the CNS.

CONCLUSION

Despite the limitations of oral and intra-nasal routes, the therapeutic potential of oral and intra-nasal administration of nano-medicines is high in cerebral ischemia treatment.

α-Cyclodextrin-Based Polypseudorotaxane Hydrogels

Supramolecular hydrogels that are based on inclusion complexes between α-cyclodextrin and (co)polymers have gained significant attention over the last decade. They are formed via dynamic noncovalent bonds, such as host-guest interactions and hydrogen bonds, between various building blocks. In contrast to typical chemical crosslinking (covalent linkages), supramolecular crosslinking is a type of physical interaction that is characterized by great flexibility and it can be used with ease to create a variety of "smart" hydrogels. Supramolecular hydrogels based on the self-assembly of polypseudorotaxanes formed by a polymer chain "guest" and α-cyclodextrin "host" are promising materials for a wide range of applications. α-cyclodextrin-based polypseudorotaxane hydrogels are an attractive platform for engineering novel functional materials due to their excellent biocompatibility, thixotropic nature, and reversible and stimuli-responsiveness properties. The aim of this review is to provide an overview of the current progress in the chemistry and methods of designing and creating α-cyclodextrin-based supramolecular polypseudorotaxane hydrogels. In the described systems, the guests are (co)polymer chains with various architectures or polymeric nanoparticles. The potential applications of such supramolecular hydrogels are also described.

Expanded access with intravenous hydroxypropyl-β-cyclodextrin to treat children and young adults with Niemann-Pick disease type C1: a case report analysis

Background

Niemann-Pick Disease Type C (NPC) is an inherited, often fatal neurovisceral lysosomal storage disease characterized by cholesterol accumulation in every cell with few known treatments. Defects in cholesterol transport cause sequestration of unesterified cholesterol within the endolysosomal system. The discovery that systemic administration of hydroxypropyl-beta cyclodextrin (HPβPD) to NPC mice could release trapped cholesterol from lysosomes, normalize cholesterol levels in the liver, and prolong life, led to expanded access use in NPC patients. HPβCD has been administered to NPC patients with approved INDs globally since 2009.

Results

Here we present safety, tolerability and efficacy data from 12 patients treated intravenously (IV) for over 7 years with HPβCD in the US and Brazil. Some patients subsequently received intrathecal (IT) treatment with HPβCD following on average 13 months of IV HPβCD. Several patients transitioned to an alternate HPβCD. Moderately affected NPC patients treated with HPβCD showed slowing of disease progression. Severely affected patients demonstrated periods of stability but eventually showed progression of disease. Neurologic and neurocognitive benefits were seen in most patients with IV alone, independent of the addition of IT administration. Physicians and caregivers reported improvements in quality of life for the patients on IV therapy. There were no safety issues, and the drug was well tolerated and easy to administer.

Conclusions

These expanded access data support the safety and potential benefit of systemic IV administration of HPβCD and provide a platform for two clinical trials to study the effect of intravenous administration of HPβCD in NPC patients.

2-Hydroxypropyl-β-cyclodextrins and the Blood-Brain Barrier: Considerations for Niemann-Pick Disease Type C1

The rare, chronic, autosomal-recessive lysosomal storage disease Niemann-Pick disease type C1 (NPC1) is characterized by progressively debilitating and ultimately fatal neurological manifestations. There is an urgent need for disease-modifying therapies that address NPC1 neurological pathophysiology, and passage through the blood-brain barrier represents an important consideration for novel NPC1 drugs. Animal investigations of 2-hydroxypropyl-β-cyclodextrins (HPβCD) in NPC1 in mice demonstrated that HPβCD does not cross the blood-brain barrier in significant amounts but suggested a potential for these complex oligosaccharides to moderately impact CNS manifestations when administered subcutaneously or intraperitoneally at very high doses; however, safety concerns regarding pulmonary toxicity were raised. Subsequent NPC1 investigations in cats demonstrated far greater HPβCD efficacy at much lower doses when the drug was administered directly to the CNS. Based on this, a phase 1/2a clinical trial was initiated with intrathecal administration of a specific, wellcharacterized mixture of HPβCD, with a tightly controlled molar substitution specification and a defined molecular "fingerprint" of the different species. The findings were very encouraging and a phase 2b/3 clinical trial has completed enrollment and is underway. In addition, phase 1 clinical studies utilizing high-dose intravenous administration of a different HPβCD are currently recruiting. Independent studies are needed for each product to satisfactorily address questions of safety, efficacy, dosing, and route of administration. The outcomes cannot be assumed to be translatable between HPβCD products and/or routes of administration.

Making Medicines Baby Size: The Challenges in Bridging the Formulation Gap in Neonatal Medicine

The development of age-appropriate formulations should focus on dosage forms that can deliver variable yet accurate doses that are safe and acceptable to the child, are matched to his/her development and ability, and avoid medication errors. However, in the past decade, the medication needs of neonates have largely been neglected. The aim of this review is to expand on what differentiates the needs of preterm and term neonates from those of the older paediatric subsets, in terms of environment of care, ability to measure and administer the dose (from the perspective of the patient and carer, the routes of administration, the device and the product), neonatal biopharmaceutics and regulatory challenges. This review offers insight into those challenges posed by the formulation of medicinal products for neonatal patients in order to support the development of clinically relevant products.

Overcoming the Blood–Brain Barrier. Challenges and Tricks for CNS Drug Delivery

Treatment of certain central nervous system disorders, including different types of cerebral malignancies, is limited by traditional oral or systemic administrations of therapeutic drugs due to possible serious side effects and/or lack of the brain penetration and, therefore, the efficacy of the drugs is diminished. During the last decade, several new technologies were developed to overcome barrier properties of cerebral capillaries. This review gives a short overview of the structural elements and anatomical features of the blood–brain barrier. The various in vitro (static and dynamic), in vivo (microdialysis), and in situ (brain perfusion) blood–brain barrier models are also presented. The drug formulations and administration options to deliver molecules effectively to the central nervous system (CNS) are presented. Nanocarriers, nanoparticles (lipid, polymeric, magnetic, gold, and carbon based nanoparticles, dendrimers, etc.), viral and peptid vectors and shuttles, sonoporation and microbubbles are briefly shown. The modulation of receptors and efflux transporters in the cell membrane can also be an effective approach to enhance brain exposure to therapeutic compounds. Intranasal administration is a noninvasive delivery route to bypass the blood–brain barrier, while direct brain administration is an invasive mode to target the brain region with therapeutic drug concentrations locally. Nowadays, both technological and mechanistic tools are available to assist in overcoming the blood–brain barrier. With these techniques more effective and even safer drugs can be developed for the treatment of devastating brain disorders.

Review of Current Strategies for Delivering Alzheimer's Disease Drugs across the Blood-Brain Barrier

Effective therapy for Alzheimer’s disease is a major challenge in the pharmaceutical sciences. There are six FDA approved drugs (e.g., donepezil, memantine) that show some effectiveness; however, they only relieve symptoms. Two factors hamper research. First, the cause of Alzheimer’s disease is not fully understood. Second, the blood-brain barrier restricts drug efficacy. This review summarized current knowledge relevant to both of these factors. First, we reviewed the pathophysiology of Alzheimer’s disease. Next, we reviewed the structural and biological properties of the blood-brain barrier. We then described the most promising drug delivery systems that have been developed in recent years; these include polymeric nanoparticles, liposomes, metallic nanoparticles and cyclodextrins. Overall, we aim to provide ideas and clues to design effective drug delivery systems for penetrating the blood-brain barrier to treat Alzheimer’s disease.

Intranasal application of PACAP and β-cyclodextrin before the "critical period of proestrous stage" can block ovulation

INTRODUCTION

It was previously shown that intracerebroventricular administration of pituitary adenylate cyclase-activating polypeptide (PACAP) prior to GnRH mobilization in proestrus prevents ovulation in rats. In this study, we examined whether PACAP given intranasally could influence luteinizing hormone (LH) and prolactin (PRL) surges and ovulation.

METHODS

On the day of proestrus PACAP, p-cyclodextrin (modifier of blood-brain barrier) or PACAP + p-cyclodextrin was applied intranasally between 12:30 and 13:00. Blood samples were taken at 16:00, 18:00, and 20:00 for measuring plasma hormone levels. In the next morning, the expelled ova were counted. p-Cyclodextrin was also administered to male and diestrous female rats between 12:30 and 13:00 and blood was taken at 18:00.

RESULTS

PACAP prevented LH and PRL surges and ovulation in about half of the rats, p-cyclodextrin alone more effectively prevented ovulation. When PACAP and p-cyclodextrin were administered together, more rats ovulated like when PACAP given alone. p-Cyclodextrin did not influence LH and PRL levels in diestrous females; however, in males, it significantly enhanced PRL level.

DISCUSSION

Not only the intracerebroventricular, but the intranasal application of PACAP prevented ovulation. p-Cyclodextrin alone is more effective than PACAP and enhances PRL levels in male rats. PACAP and p-cyclodextrin given together weaken each other's effect. p-Cyclodextrin, as excipient of various drugs, has to be used carefully in human medications.

β-Cyclodextrin and oleic acid increase levels of dopamine and potentiates oxidative damage in young and adult rat brain

Background

Cyclodextrins are active pharmaceutical ingredients to treat neurological diseases by reducing neurotoxicity. The aim of this study was to test if combined consumption of β-cyclodextrin (BCD) and Oleic acid (OA) potentiates brain antioxidant protection.

Methods

Four groups of young Wistar rats, grouped in 6 animals each, were treated as follows: Group (G) 1, saline solution 0.9% (control); G2, BCD (0.7 g/kg); G3, OA (15 ml/kg); G4, BCD + OA. The same design was assayed for groups of adult rats. Treatments were daily administered by oral means for five consecutive days. On the last day of administration, brains of the animals were extracted to measure dopamine, 5-HIAA, glutathione (GSH), ATPase, Lipoperoxidation and H₂O_2.

Results

Oleic acid and β-cyclodextrin upgraded the levels of dopamine, 5-HIAA and lipid peroxidation and downgraded the concentrations of GSH and H₂O₂ in cortex, hemispheres (striatum) and cerebellum/medulla oblongata regions.

Conclusions

The results of the present study suggest that combined use of oleic acid and β-cyclodextrin may increase oxidative damage in brain regions and promote alteration in dopamine and 5-HIAA amines and hence, constitutes health risks among age of subjects.

Cyclodextrins: Assessing the Impact of Cavity Size, Occupancy, and Substitutions on Cytotoxicity and Cholesterol Homeostasis

Cyclodextrins (CDs) are cyclic oligosaccharides; the most common CDs contain six, seven, or eight glucose units called α-CDs, β-CDs, and γ-CDs, respectively. The use of CDs in biomedical research is increasing due to their ability to interact with membrane lipids as well as a wide variety of poorly water-soluble molecules. We assessed the impact of CD cavity size, occupancy, and substitutions on cytotoxicity and cholesterol homeostasis. The potency of CD-mediated cytotoxicity was in the order of β-CDs, α-CDs, and γ-CDs. Substitutions with hydroxypropyl or carboxymethyl group attenuated cytotoxicity compared with the native CDs, whereas CDs substituted with methyl groups exhibited cytotoxicity that was similar to that of the native CDs. The lipid components in blood exerted remarkable hemolysis-alleviating effects in methyl-β-CD-induced hemolysis. Occupancy of the CD cavity with cholesterol or a structurally related lipid molecule abrogated the cytotoxic capacity of the CDs. Interestingly, hydroxypropyl-γ-CD (HPγCD) was able to reduce intracellular cholesterol accumulation in Niemann–Pick disease type C (NPC) patient-derived fibroblasts as efficiently as HPβCD. Proteomic study indicated that HPβCD and HPγCD treatments altered the expression pattern of cellular proteins, suggesting that some of the CD-induced cellular proteins may play an important function in modulating intracellular cholesterol homeostasis.

Neural stem cells for disease modeling and evaluation of therapeutics for infantile (CLN1/PPT1) and late infantile (CLN2/TPP1) neuronal ceroid lipofuscinoses

BACKGROUND

Infantile and late infantile neuronal ceroid lipofuscinoses (NCLs) are lysosomal storage diseases affecting the central nervous system (CNS). The infantile NCL (INCL) is caused by mutations in the PPT1 gene and late-infantile NCL (LINCL) is due to mutations in the TPP1 gene. Deficiency in PPT1 or TPP1 enzyme function results in lysosomal accumulation of pathological lipofuscin-like material in the patient cells. There is currently no small-molecular drug treatment for NCLs.

RESULTS

We have generated induced pluripotent stem cells (iPSC) from three patient dermal fibroblast lines and further differentiated them into neural stem cells (NSCs). Using these new disease models, we evaluated the effect of δ-tocopherol (DT) and hydroxypropyl-β-cyclodextrin (HPBCD) with the enzyme replacement therapy as the control. Treatment with the relevant recombinant enzyme or DT significantly ameliorated the lipid accumulation and lysosomal enlargement in the disease cells. A combination therapy of δ-tocopherol and HPBCD further improved the effect compared to that of either drug used as a single therapy.

CONCLUSION

The results demonstrate that these patient iPSC derived NCL NSCs are valid cell- based disease models with characteristic disease phenotypes that can be used for study of disease pathophysiology and drug development.

Supramolecular Pharmaceutical Sciences: A Novel Concept Combining Pharmaceutical Sciences and Supramolecular Chemistry with a Focus on Cyclodextrin-Based Supermolecules

Supramolecular chemistry is an extremely useful and important domain for understanding pharmaceutical sciences because various physiological reactions and drug activities are based on supramolecular chemistry. However, it is not a major domain in the pharmaceutical field. In this review, we propose a new concept in pharmaceutical sciences termed "supramolecular pharmaceutical sciences," which combines pharmaceutical sciences and supramolecular chemistry. This concept could be useful for developing new ideas, methods, hypotheses, strategies, materials, and mechanisms in pharmaceutical sciences. Herein, we focus on cyclodextrin (CyD)-based supermolecules, because CyDs have been used not only as pharmaceutical excipients or active pharmaceutical ingredients but also as components of supermolecules.

HP-β-cyclodextrin as an inhibitor of amyloid-β aggregation and toxicity

Amyloid deposits of misfolded amyloid-β protein (Aβ) on neuronal cells are a pathological hallmark of Alzheimer's disease (AD). Prevention of the abnormal Aβ aggregation has been considered as a promising therapeutic strategy for AD treatment. To prevent reinventing the wheel, we proposed to search the existing drug database for other diseases to identify potential Aβ inhibitors. Herein, we reported the inhibitory activity of HP-β-cyclodextrin (HP-β-CD), a well-known sugar used in drug delivery, genetic vector, environmental protection and treatment of Niemann-Pick disease type C1 (NPC1), against Aβ1-42 aggregation and Aβ-induced toxicity, with the aim of adding a new function as a sugar-based Aβ inhibitor. Experimental data showed that HP-β-CD molecules were not only nontoxic to cells, but also greatly inhibited Aβ fibrillization and reduced Aβ-induced toxicity in a concentration-dependent manner. At an optimal molar ratio of Aβ : HP-β-CD = 1 : 2, HP-β-CD enabled the reduction of 60% of Aβ fibrils and increased the cell viability to 92%. Such concentration-dependent inhibitor capacity of HP-β-CD was likely attributed to several combined effects, including the enhancement of Aβ-HP-β-CD interactions, prevention of structural transition of Aβ peptides towards β-sheet structures, and reduction of self-aggregation of HP-β-CD. In parallel, molecular simulations further revealed the atomic details of HP-β-CD interacting with the Aβ oligomer, showing that HP-β-CD had a high tendency to interact with hydrophobic residues of Aβ in two β-strands and the N-terminal tail. More importantly, we identified that the inner hydrophobic cavity of HP-β-CD was a key active site for Aβ inhibition. Once the inner cavity of HP-β-CD was blocked by a small hydrophobic molecule of ferulic acid, HP-β-CD completely lost its inhibition capacity against Aβ. Given the already established pharmaceutical functions of HP-β-CD in drug delivery, our findings suggest that HP-β-CD has great potential to be designed as a sugar-based Aβ inhibitor.

Enhancing both oral bioavailability and brain penetration of puerarin using borneol in combination with preparation technologies

Now there are few good oral preparations of puerarin used in cerebrovascular diseases because of its poor oral absorption caused by the low water solubility and the poor penetration into brain. In this study, three oral formulations of puerarin, nanocrystals suspension (NCS), inclusion compounds solution (ICS) and self-microemulsifying drug delivery system (SMEDDS) were prepared with borneol as an oral brain-targeting enhancer. A rat syngeneic in vitro model of the brain-blood barrier (BBB) was established to investigate effects of borneol on the permeability of puerarin across the BBB. The pharmacokinetics of puerarin in mice after oral administration was investigated by a high performance liquid chromatography-mass spectrometry/mass spectrometry (HPLC-MS/MS) method. The in vitro BBB model study showed the permeability of puerarin was increased significantly (p < 0.05) and the value of transepithelial electrical resistance at 2 h was decreased significantly (p < 0.01) when the concentration of borneol was over 12.5 μg/mL compared with the control group. The pharmacokinetics results indicated borneol with doses of over 50 mg/kg could obviously increase both intestinal absorption and brain penetration of puerarin. With co-administration of borneol (100 mg/kg), the AUC of puerarin both in plasma (AUCplasma) and in brain (AUCbrain) for SMEDDS were significantly higher than those for NCS (p < 0.01) and ICS (p < 0.05). These results suggested borneol in combination with SMEDDS could improve both the oral absorption and the brain penetration of puerarin in mice, which was promising for the development of an oral formulation of puerarin used in cerebrovascular diseases.

Is 2-Hydroxypropyl-β-cyclodextrin a Suitable Carrier for Central Administration of Δ9 -Tetrahydrocannabinol? Preclinical Evidence

Preclinical Research Δ⁹ -Tetrahydrocannabinol (THC) is a hydrophobic compound that has a potent antinociceptive effect in animals after intrathecal (IT) or intracerebroventricular (ICV) administration. The lack of a suitable solvent precludes its IT administration in humans. 2-Hydroxypropyl-β-cyclodextrin (HPβCD) increases the water solubility of hydrophobic drugs and is approved for IT administration in humans. To investigate whether HPβCD might be a suitable carrier for ICV administration of THC in rats, two formulations containing THC complexed with HPβCD (30 and 135 μg of THC per animal) and vehicle were administered to Wistar rats. The antinociceptive effect (using the tail flick test), locomotor activity, and body temperature were evaluated. ICV injection of 135 μg of THC/HPβCD complex increased tail flick latency, reduced locomotor activity, and had a dual effect on body temperature. The 30 μg THC/HPβCD formulation only produced a hyperthermic effect. All animals appeared healthy, with no difference between the groups. These results were similar to those obtained in other preclinical studies in which THC was administered centrally using solvents that are unsuitable for IT administration in humans because of their toxicity. Our findings suggest that HPβCD may be a useful carrier for IT administration of THC in humans. Drug Dev Res 78 : 411-419, 2017. © 2017 Wiley Periodicals, Inc.