Characterisation and antiproliferative activity of irinotecan and sulphonatocalixarene inclusion complex

Synthesis, characterization, and application of honey stabilized inulin nanoparticles as colon targeting drug delivery carrier

Inulin (INU) is a versatile natural polysaccharide primarily derived from chicory roots. INU possesses the unique quality of evading digestion or fermentation in the early stages of the human digestive tract, instead reaching the lower colon directly. Exploiting on this distinctive attribute, INU finds application in the creation of targeted carrier systems for delivering drugs tailored to colon-related diseases. This study presents a novel method for synthesizing highly stable and non-aggregatory inulin nanoparticles (INU NPs) by ionotropic gelation method, using calcium chloride as crosslinker and natural honey as a stabilizing agent. Different formulation and process parameters were optimized for the synthesis of monodispersed INU NPs. These INU NPs efficiently encapsulated a hydrophilic drug irinotecan hydrochloride trihydrate (IHT) and drug loaded formulation (IINPs) demonstrated excellent colloidal and storage stabilities. Notably, these IINPs exhibited pH-dependent drug release, suggesting potential for colon-specific drug delivery. Anticancer activity of the NPs was found significantly higher in comparison to IHT through cytotoxicity and apoptosis studies against human colorectal carcinoma cells. Overall, this study revealed that the INU NPs synthesized by ionotropic gelation will be an efficient nanocarrier system for colon-targeted drug delivery due to their exceptional biocompatibility and stability in stomach and upper intestinal conditions.

An eco-friendly extraction and purification method of nuciferine from Folium nelumbinis with p-sulfonatocalix[6]arenes

INTRODUCTION

Folium nelumbinis is used as vegetable, functional food and herbal medicine in Asia. p-Sulfonatocalix[6]arene (SC6A) is a water-soluble supramolecular macrocycle and has never been applied to the extraction of herbal products.

OBJECTIVE

In this study, SC6A-assisted extraction of nuciferine from Folium nelumbinis has been carried out to develop an eco-friendly extraction process with high extraction efficacy and easy operation.

METHODS

Single-factor experiments were adopted to obtain the optimal conditions for the SC6A-assisted extraction of nuciferine from Folium nelumbinis, and then nuciferine and SC6A were separated easily by one-step alkalization. The host-guest complexes between nuciferine and SC6A were analyzed by competitive fluorescence titration, DSC, FT-IR and ¹ H-NMR.

RESULTS

The optimal SC6A/Folium nelumbinis/solution ratio for extraction was 0.4:1:20 (g/g/mL), with a granulometric fraction below 180 μm and an extraction time of 1 h with soaking. The purity and recovery of nuciferine extracted with SC6A were increased 29.24 and 35.73 times compared with extraction with aqueous solution, respectively. Moreover, a good reusability of SC6A in the extraction of nuciferine was demonstrated. Competitive fluorescence titration, DSC, FT-IR and ¹ H-NMR characterization indicated that SC6A could form host-guest complexes with nuciferine at a ratio of 1:1.

CONCLUSION

The study provided an eco-friendly, safe and effective nuciferine extraction method, which can be used for the development of nutrition supplements containing nuciferine.

Anthocyanin Color Stabilization by Host-Guest Complexation with p-Sulfonatocalix[n]arenes

Flavylium-based compounds in their acidic and cationic form bring color to aqueous solutions, while under slightly acidic or neutral conditions they commonly bring discoloration. Selective host-guest complexation between water-soluble p-sulfonatocalix[n]arenes (SCn) macrocycles and the flavylium cationic species can increase the stability of the colored form, expanding its domain over the pH scale. The association constants between SCn and the cationic (acid) and neutral basic forms of flavylium-based compounds were determined through UV-Vis host-guest titrations at different pH values. The affinity of the hosts for synthetic chromophore was found to be higher than for a natural anthocyanin (Oenin). The higher affinity of SC4 for the synthetic flavylium was confirmed by ¹H NMR showing a preferential interaction of the flavylium phenyl ring with the host cavity. In contrast with its synthetic counterpart, the flavylium substitution pattern in the anthocyanin seems to limit the inclusion of the guest in the host’s binding pocket. In this case, the higher affinity was observed for the octamer (SC8) likely due to its larger cavity and higher number of negatively charged sulfonate groups.

Serotonin-Functionalized Vit-E Nanomicelles for Targeting of Irinotecan to Prostate Cancer Cells

Receptor-mediated endocytosis is key in the success of targeted nanomedicines for the treatment of cancer. Various receptors have been explored for the active targeting of anticancer drugs to avoid the drawbacks of conventional anticancer drugs. This research work aimed to investigate the potential of serotonin (ST)-conjugated Vit-E nanomicelles for the targeted delivery of irinotecan hydrochloride (IRI) to human prostate cancer cells. A ST receptor-targeting conjugate was synthesized by conjugating ST and d-α-tocopheryl polyethylene glycol succinate via a two-step synthesis reaction. The developed formulation demonstrated a size of about 14 nm, a negative zeta potential of around -20 mV, a high drug encapsulation efficiency, and sustained drug release over 48 h. Cytotoxicity studies revealed that ST-conjugated, IRI-loaded nanomicelles (IRI-STNM) were not only toxic to human prostate cancer cells but also eradicate these cells present in the form of 3D spheroids. This cytotoxicity of IRI-STNM was mediated through induction of apoptosis, reactive oxygen species generation, change in mitochondrial membrane potential, and inhibition of cell migration. Further, IRI-STNM performed significantly better than the native IRI and nontargeted nanomicelles, which was led by a higher cellular uptake of IRI-STNM, indicating the role of ST in targeting of drug-loaded nanomicelles.

Supramolecular prodrugs based on host–guest interactions

The concept, detailed progress, advantages and opportunities of supramolecular drugs via host–guest chemistry are summarized.

Irinotecan hydrochloride trihydrate loaded folic acid-tailored solid lipid nanoparticles for targeting colorectal cancer: development, characterization, and in vitro cytotoxicity study using HT-29 cells

Aim: The aim of this investigation was to evaluate the potential of folic acid-tailored solid lipid nanoparticles (SLNs) for encapsulation as well as for in vitro cytotoxicity study of irinotecan hydrochloride trihydrate (IHT) against colorectal cancer (CRC) by using HT-29 cells. Methods: Solvent diffusion technique was employed for the preparation of SLNs. Further, the formulations were optimised via three-level, three-factor Box-Behnken design (BBD). Results: The uncoupled SLNs (IRSLNs) and folic acid-coupled SLNs (IRSLNFs) formulations revealed not only high %entrapment efficiency but also small particle size. Moreover, in vitro drug release results from IRSLNs and IRSLNFs confirmed that they followed sustained-release effect for up to 144 h. Whereas, in vitro cell viability study against HT-29 cell line suggested significantly (p < 0.05) higher cytotoxicity (IC₅₀ = 15 µg/ml) of IRSLNFs over IRSLNs and IHT solution. Conclusions: Outcomes suggested that the engineered IRSLNFs hold great potential for targeting CRC for an extended period of time.

Amphiphilic p-sulfonatocalix[4]arene as "drug chaperone" for escorting anticancer drugs

Supramolecularly constructing multifunctional platform for drug delivery is a challenging task. In this work, we propose a novel supramolecular strategy “drug chaperone”, in which macrocyclic amphiphiles directly coassemble with cationic drugs into a multifunctional platform and its surface is further decorated with targeting ligands through host–guest recognition. The coassembling and hierarchical decoration processes were monitored by optical transmittance measurements, and the size and morphology of amphiphilic coassemblies were identified by dynamic light scattering and high-resolution transmission electron microscopy. In cell experiments to validate the drug chaperone strategy, the anticancer activities of free drugs were pronouncedly improved by coassembling with amphiphilic chaperone and further functionalization with targeting ligand.

Supramolecular chemistry of p-sulfonatocalix[n]arenes and its biological applications

CONSPECTUS: Developments in macrocyclic chemistry have led to supramolecular chemistry, a field that has attracted increasing attention among researchers in various disciplines. Notably, the discoveries of new types of macrocyclic hosts have served as important milestones in the field. Researchers have explored the supramolecular chemistry of several classical macrocyclic hosts, including crown ethers, cyclodextrins, calixarenes, and cucurbiturils. Calixarenes represent a third generation of supramolecular hosts after cyclodextrins and crown ethers. Easily modified, these macrocycles show great potential as simple scaffolds to build podand-like receptors. However, the inclusion properties of the cavities of unmodified calixarenes are not as good as those of other common macrocycles. Calixarenes require extensive chemical modifications to achieve efficient endo-complexation. p-Sulfonatocalix[n]arenes (SCnAs, n = 4-8) are a family of water-soluble calixarene derivatives that in aqueous media bind to guest molecules in their cavities. Their cavities are three-dimensional and π-electron-rich with multiple sulfonate groups, which endow them with fascinating affinities and selectivities, especially toward organic cations. They also can serve as scaffolds for functional, responsive host-guest systems. Moreover, SCnAs are biocompatible, which makes them potentially useful for diverse life sciences and pharmaceutical applications. In this Account, we summarize recent work on the recognition and assembly properties unique to SCnAs and their potential biological applications, by our group and by other laboratories. Initially examining simple host-guest systems, we describe the development of a series of functional host-guest pairs based on the molecular recognition between SCnAs and guest molecules. Such pairs can be used for fluorescent sensing systems, enzymatic activity assays, and pesticide detoxification. Although most macrocyclic hosts prevent self-aggregation of guest molecules, SCnAs can induce self-aggregation. Researchers have exploited calixarene-induced aggregation to construct supramolecular binary vesicles. These vesicles respond to internal and external stimuli, including temperature changes, redox reactions, additives, and enzymatic reactions. Such structures could be used as drug delivery vehicles. Although several biological applications of SCnAs have been reported, this field is still in its infancy. Continued exploration of the supramolecular chemistry of SCnAs will not only improve the existing biological functions but also open new avenues for the use of SCnAs in the fields of biology, biotechnology, and pharmaceutical research. In addition, we expect that other interdisciplinary research efforts will accelerate developments in the supramolecular chemistry of SCnAs.