β-Cyclodextrin-Based Inclusion Complexation Bridged Biodegradable Self-Assembly Macromolecular Micelle for the Delivery of Paclitaxel

13-Weeks subchronic toxicity of isoquercitrin-γ-cyclodextrin (IQC-γCD) molecular inclusion complex in Sprague-Dawley rats

Flavonoids such as quercetin and its glycoside Isoquercitrin and are abundantly present in the diet and have various pharmacological effects. However, limited data about its potential toxicity is available. In this study, we aim to evaluate the subchronic toxicity of the isoquercitrin-γ-cyclodextrin (IQC-γCD) molecular inclusion complex (SunActive® QCD/EN) in Sprague-Dawley (SD) rats. The IQC-γCD was administrated orally to 40 male and 40 female SD rats at dietary doses up to 5.0 % for 13 consecutive weeks. During the experiment periods, the general clinical signs, mortality, hematological, urinalysis values, biochemical, and histopathological parameters were examined. All animals survived until the scheduled necropsy, and no statistically significant or clinical sign of toxicologically relevant differences including pathology parameters, and histopathological endpoints were observed in any of the IQC-γCD treatment groups, compared with the control group. However, certain observations were noted in the male rats treated with the highest concentration (5.0 %), but these were not seen in female rats. A slight inhibition of weight gain was observed, probably linked to a fall in red blood cells, and hematocrit index in female rats. Statistically significant changes were noted in some clinical measures, such as plasma bilirubin level, alkaline phosphatase total bile acid without evidence of systemic clinical toxicity. The results support no observed adverse effect level (NOAEL) of IQC-γCD of 5.0 % in the diet for males (3338.55 mg/kg/day), and 3.0 % in the diet for females (2177.33 mg/kg/day) SD rats. Therefore, in this 13 weeks repeated-dose SD rat study there were no treatment-related adverse clinical or pathological findings for IQC-γCD of 5.0 % in the diet for males, and 3.0 % in the diet for females SD rats. The results of the present study support the safe use of IQC-γCD as a functional food, food additive, and natural ingredient.

Visible Light-Curable Hydrogel Systems for Tissue Engineering and Drug Delivery

Visible light-curable hydrogels have been investigated as tissue engineering scaffolds and drug delivery carriers due to their physicochemical and biological properties such as porosity, reservoirs for drugs/growth factors, and similarity to living tissue. The physical properties of hydrogels used in biomedical applications can be controlled by polymer concentration, cross-linking density, and light irradiation time. The aim of this review chapter is to outline the results of previous research on visible light-curable hydrogel systems. In the first section, we will introduce photo-initiators and mechanisms for visible light curing. In the next section, hydrogel applications as drug delivery carriers will be emphasized. Finally, cellular interactions and applications in tissue engineering will be discussed.

Supramolecular Polysaccharide Nanotheranostics that Inhibit Cancer Cells Growth and Monitor Targeted Therapy Response

Targeted anticancer therapies directed against specific molecular drivers of tumors are emerging as effective treatment strategies, however, monitoring their response is still challenging. Current clinical imaging techniques that measure either morphological or metabolic changes in the tumor are not always indicative of clinical outcome due to delayed or variable responses. Here, dual-stage polysaccharide-based supramolecular nanotheranostics (SPN) were designed that enable co-delivery of kinase inhibitor and an activatable imaging probe.

Methods: The SPNs were prepared by supramolecular assembly of two components, polysaccharide construct conjugated with kinase inhibitor-function activatable probe and kinase inhibitor- β-cyclodextrin conjugate. Physiochemical characterization of SPNs including size, stability, zeta potential and pH-responsiveness of the assembly was performed. The efficacy of SPNs in inducing cancer cell death by inhibition of kinase signaling and imaging the response was evaluated in murine BRAFV^600E melanoma (D4M) and triple-negative breast cancer (4T1) cell lines. Finally, the in vivo efficacy was investigated in D4M melanoma tumor model.

Results: The polysaccharide-constructs along with kinase inhibitor- β-cyclodextrin conjugates self-assemble to produce SPNs of around 200 nm in diameter and were stable for over a week under physiologically relevant conditions. The SPNs exhibited enhanced cytotoxic effect and significant inhibition of kinase signaling as compared to the free inhibitor. In vitro imaging studies confirmed their enzyme-activatable therapy response tracking abilities both in cancer cells and tumor spheroids. Furthermore, SPN treated mice exhibited better tumor growth inhibition as compared to the control groups and therapy response could be imaged at both early (24-48h) and later time points.

Conclusion: These findings demonstrate that the supramolecular polysaccharide nanotheranostics can not only inhibit kinase signaling pathway in aggressive tumor, but also monitor targeted therapy response early.

Supramolecular Fluorine Magnetic Resonance Spectroscopy Probe Polymer Based on Passerini Bifunctional Monomer

A water-soluble fluorine magnetic resonance spectroscopy host-guest probe, P(HPA-co-AdamCF₃A), was successfully constructed from the facile synthesis of a bifunctional monomer via a quantitative Passerini reaction. Supramolecular complexation with (2-hydroxypropyl)-β-cyclodextrin promoted a change in the chemical environment, leading to modulation of both the relaxation properties as well as chemical shift of the fluorine moieties. This change was used to probe the supramolecular interaction by ¹⁹F MRI spectroscopy and give insight into fluorine probe formulation. This work provides a fundamental basis for an ¹⁹F MR imaging tracer capable of assessing host-guest inclusion and a potential model to follow the fate of a drug delivery system in vivo.

Molecular Modeling-Based Delivery System Enhances Everolimus-Induced Apoptosis in Caco-2 Cells

Several studies have shown that the mammalian target of rapamycin (mTOR) inhibitor; everolimus (EV) improves patient survival in several types of cancer. However, the meaningful efficacy of EV as a single agent for the treatment of colorectal cancer (CRC) has failed to be proven in multiple clinical trials. Combination therapy is one of the options that could increase the efficacy and decrease the toxicity of the anticancer therapy. This study revealed that the β-cyclodextrin (β-CD):FGF7 complex has the potential to improve the antiproliferative effect of EV by preventing FGF receptor activation and by enhancing EV cellular uptake and intracellular retention. Molecular docking techniques were used to investigate the possible interaction between EV, β-CD, and FGF7. Molecular docking insights revealed that β-CD and EV are capable to form a stable inclusion complex with FGF at the molecular level. The aqueous solubility of the inclusion complex was increased (3.1 ± 0.23 μM) when compared to the aqueous solubility of pure EV (1.7 ± 0.16 μM). In addition, the in vitro cytotoxic activity of a FGF7:β-CD:EV complex on Caco-2 cell line was investigated using real-time xCELLigence technology. The FGF7:β-CD:EV complex has induced apoptosis of Caco-2 cells and shown higher cytotoxic activity than the parent drug EV. With the multitargets effect of β-CD:FGF7 and EV, the antiproliferative effect of EV was remarkably improved as the IC₅₀ value of EV was reduced from 9.65 ± 1.42 to 1.87 ± 0.33 μM when compared to FGF7:β-CD:EV complex activity. In conclusion, the findings advance the understanding of the biological combinational effects of the β-CD:FGF7 complex and EV as an effective treatment to combat CRC.

Photo-Cured Glycol Chitosan Hydrogel for Ovarian Cancer Drug Delivery

In this study, we prepared an injectable drug delivery depot system based on a visible light-cured glycol chitosan (GC) hydrogel containing paclitaxel (PTX)-complexed beta-cyclodextrin (β-CD) (GC/CD/PTX) for ovarian cancer (OC) therapy using a tumor-bearing mouse model. The hydrogel depot system had a 23.8 Pa of storage modulus at 100 rad/s after visible light irradiation for 10 s. In addition, GC was swollen as a function of time. However, GC had no degradation with the time change. Eventually, the swollen GC matrix affected the releases of PTX and CD/PTX. GC/PTX and GC/CD/PTX exhibited a controlled release of PTX for 7 days. In addition, GC/CD/PTX had a rapid PTX release for 7 days due to improved water solubility of PTX through CD/PTX complex. In vitro cell viability tests showed that GC/CD/PTX had a lower cell viability percentage than the free PTX solution and GC/PTX. Additionally, GC/CD/PTX resulted in a superior antitumor effect against OC. Consequently, we suggest that the GC/CD system might have clinical potential for OC therapy by improving the water solubility of PTX, as PTX is included into the cavity of β-CD.

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.

Current development in the formulations of non-injection administration of paclitaxel

Paclitaxel (PTX) belongs to a class of taxane anti-tumor drug used for the clinic treatment of breast cancer, ovarian cancer, non-small-cell lung cancer, and so on. PTX has poor water solubility and oral bioavailability. It is generally administered via intravenous (i.v.) infusion. Traditional PTX injectable preparations contain Cremophor-EL and ethanol to improve its solubility, which would result in adverse reactions like severe hypersensitivity, neutropenia, etc. Adverse reactions can be reduced only by complicated pretreatment with glucocorticoid and antihistamines drugs and followed by PTX slow infusion for three hours, which has brought significant inconvenience to the patients. Though, a new-generation PTX formulation, Abraxane, free of Cremophor-EL and ethanol, is still being administrated by frequent i.v. infusions and extremely expensive. Therefore, non-injection administration of PTX is urgently needed to avoid the side effects as well as reduce inconvenience to the patients. Recently, a variety of non-injection drug delivery systems (DDSs) of PTX have been developed. This review aims to discuss the progress of non-injectable administration systems of PTX, including oral administration systems, vaginal administration systems, implantable DDSs, transdermal DDSs and intranasal administration for the future study and clinical applications.

Dendron-Grafted Polylysine-Based Dual-Modal Nanoprobe for Ultra-Early Diagnosis of Pancreatic Precancerosis via Targeting a Urokinase-Type Plasminogen Activator Receptor

Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer death. Early detection of precancerous pancreatic intraepithelial neoplasia (PanIN) tissues is an urgent challenge to improve the PDAC prognosis. Here, a urokinase-type plasminogen activator receptor (uPAR)-targeted magnetic resonance (MR)/near-infrared fluorescence (NIRF) dual-modal nanoprobe dendron-grafted polylysine (DGL)-U11 for ultra-early detection of pancreatic precancerosis is reported. Because of its good biocompatibility and biodegradability, globular architecture, and well-defined reactive groups, the DGL is chosen as the platform to load with a pancreatic tumor-targeting peptide U11, a magnetic resonance contrast agent Gd3+ -diethylene triamine pentaacetic acid, and a near-infrared fluorescent cyanine dye Cy5.5. The nanoprobe DGL-U11 has several preferable characteristics, such as active peptide targeting to activator receptor, good biocompatibility, dual-modal imaging diagnosis, and well controlled diameter in a range of 15-25 nm. Upon incorporation of the active U11 peptide target to the overexpressed activator receptor uPAR, the targeted nanoprobe DGL-U11 can increase to the earlier PanIN-II stage through in vivo NIRF imaging. Labeled with both MR and NIRF bioimaging reporters, the uPAR-targeted dual-modal nanoprobe is very effective in the targeted imaging of precancerous PanINs and PDAC lesions with high sensitivity and spatial resolution, providing a promising platform to the ultra-early detection of PDAC.

Identification of allosteric inhibitors of the ecto-5'-nucleotidase (CD73) targeting the dimer interface

The ecto-5'-nucleotidase CD73 plays an important role in the production of immune-suppressive adenosine in tumor micro-environment, and has become a validated drug target in oncology. Indeed, the anticancer immune response involves extracellular ATP to block cell proliferation through T-cell activation. However, in the tumor micro-environment, two extracellular membrane-bound enzymes (CD39 and CD73) are overexpressed and hydrolyze efficiently ATP into AMP then further into immune-suppressive adenosine. To circumvent the impact of CD73-generated adenosine, we applied an original bioinformatics approach to identify new allosteric inhibitors targeting the dimerization interface of CD73, which should impair the large dynamic motions required for its enzymatic function. Several hit compounds issued from virtual screening campaigns showed a potent inhibition of recombinant CD73 with inhibition constants in the low micromolar range and exhibited a non-competitive inhibition mode. The structure-activity relationships studies indicated that several amino acid residues (D366, H456, K471, Y484 and E543 for polar interactions and G453-454, I455, H456, L475, V542 and G544 for hydrophobic contacts) located at the dimerization interface are involved in the tight binding of hit compounds and likely contributed for their inhibitory activity. Overall, the gathered information will guide the upcoming lead optimization phase that may lead to potent and selective CD73 inhibitors, able to restore the anticancer immune response.

Gold nanoparticles stabilized with βcyclodextrin-2-amino-4-(4-chlorophenyl)thiazole complex: A novel system for drug transport

While 2-amino-4-(4-chlorophenyl)thiazole (AT) drug and thiazole derivatives have several biological applications, these compounds present some drawbacks, such as low aqueous solubility and instability. A new complex of βCD-AT has been synthesized to increase AT solubility and has been used as a substrate for the deposit of solid-state AuNPs via magnetron sputtering, thus forming the βCD-AT-AuNPs ternary system, which is stable in solution. Complex formation has been confirmed through powder X-ray diffraction and 1D and 2D nuclear magnetic resonance. Importantly, the amine and sulfide groups of AT remained exposed and can interact with the surfaces of the AuNPs. The complex association constant (970 M^-1) has been determined using phase solubility analysis. AuNPs formation (32 nm average diameter) has been studied by UV-Visible spectroscopy, transmission/scanning electron microscopy and energy-dispersive X-ray analysis. The in vitro permeability assays show that effective permeability of AT increased using βCD. In contrast, the ternary system did not have the capacity to diffuse through the membrane. Nevertheless, the antibacterial assays have demonstrated that AT is transferred from βCD-AT-AuNPs, being available to exert its antibacterial activity. In conclusion, this novel βCD-AT-AuNPs ternary system is a promising alternative to improve the delivery of AT drugs in therapy.