Folate receptor targeted bufalin/β-cyclodextrin supramolecular inclusion complex for enhanced solubility and anti-tumor efficiency of bufalin

Cyclodextrin inclusion complex enhances solubility and antimicrobial activity of chlortetracycline hydrochloride

Chlortetracycline hydrochloride (CTC) is a broad-spectrum tetracycline antibiotic used to prevent or resist different bacterial infections. However, due to its poor aqueous stability and physicochemical instability, its clinical development is limited. To improve such properties, CTC complexation with β-cyclodextrin (β-CD) and 2-hydroxypropanol-β-cyclodextrin (HP-β-CD) was performed using different preparation techniques (Freeze drying and ball milling). Inclusion complexes were comprehensively characterized using different analytical techniques and showed different properties distinct to pure CTC. In the presence of both CDs, CTC solubility was significantly improved. After ratio optimization, the optimal molar ratio after freeze-drying was determined to be 1:5. Compared to pure CTC powder (4 mg/mL), the solubility of CTC/HP-β-CD improved approximately 9 times (36 mg/mL), and a new CTC injection was successfully prepared. The antibacterial activity (in vivo and in vitro) of the CTC/HP-β-CD injection was then examined in natural infection chickens. Pathological tissue images showed that a 20 mg/kg CTC/HP-β-CD dose increased antibacterial activity and therapeutic effects. Additionally, we determined five clinical strains and statistically verified that CTC/HP-β-CD exhibits stronger antibacterial activity compared to CTC and other tetracycline drugs, with the most significant effect observed against Pseudomonas aeruginosa (MIC value of 2 μg/mL). Thus, these findings suggest that CTC/HP-β-CD inclusion complexes could be promising for pharmaceutical development, warranting further clinical evaluation, as solubility was significantly increased, and enhanced antibacterial activity was recorded in vivo and in vitro.

Synthesis of β-Cyclodextrin-Functionalized Silver Nanoparticles and Their Application for Loading Cytisine and Its Phosphorus Derivative

In this study, the synthesis and properties of β-cyclodextrin-functionalized silver nanoparticles and their loading with a drug component are considered. β-Cyclodextrin was used as a reducing agent and stabilizer in the preparation of silver nanoparticles. The use of β-CD-AgNPs in loading molecules of the alkaloid cytisine (Cz) and its O,O-dimethyl-N-cytisinilphosphate (CzP) derivative, which have pronounced antiviral properties, was studied. The formation of β-CD-Cz-AgNPs and β-CD-CzP-AgNPs was confirmed by UV spectroscopy and X-ray diffraction spectroscopy. Scanning electron microscopy and transmission electron microscopy showed that the obtained β-CD-Cz-AgNP and β-CD-CzP-AgNP nanocomposites were well dispersed with particle sizes in the range of 3-20 nm. 1H-, 13C-NMR and COSY, HMQC, HMBC and Fourier transform infrared spectroscopy revealed the reduction and encapsulation of AgNPs by β-Cz, and the TEM imaging results showed an increase in the size of nanoparticles after the introduction of cytisine and its phosphorus derivative. The kinetic parameters of the thermal degradation process of β-CD, Cz, CzP and their inclusion complexes Cz(CzP)-β-CD-AgNPs under isothermal conditions, which ensure the preservation of the kinetic triplet, were determined. The differences in the mechanism of thermal decomposition of the studied materials are described by the parameters of the Šesták-Berggren model (m and n), which demonstrated differences for different compounds: for β-CD, the values of the parameters m and n are 0.47 and 0.53, respectively, while for CzP-β-CD-AgNPs they reach values of 0.66 and 1.34. These results indicate differences in the mechanism of thermal decomposition of the studied materials.

Significantly improving the solubility and anti-inflammatory activity of fenofibric acid with native and methyl-substituted beta-cyclodextrins via complexation

The solubility of commonly used anti-inflammatory drugs has become a significant concern in contemporary medicine. Furthermore, inflammatory arthritis stands out as the most prevalent chronic inflammatory disease globally. The disease's pathology is characterized by heightened inflammation and oxidative stress, culminating in chronic pain and the loss of joint functionality. Fenofibric acid (FFA) exhibits notable anti-inflammatory potential. This research assesses the anti-inflammatory effects of FFA, both in its standalone form and as inclusion complexes (ICs) with β-cyclodextrin and its methyl derivatives. FFA is encapsulated within the cavities of cyclodextrins (CDs), a fact confirmed by spectral changes observed in FFA. Distinct rock and seed-like morphologies are apparent for FFA with CDs, indicating that the CDs have influenced the surface of the guest. The introduction of CDs significantly enhances the thermal stability of FFA. ICs demonstrate superior results in inflammation activity compared to FFA alone. The efficacy of FFA complexed with CDs in mitigating inflammation positions it as a promising new drug. Additionally, our findings reveal that incorporating FFA into the CD cavity as a drug release system enhances the pharmacological profile of this substance, FFA.

Responsive Supramolecular Nanomicelles Formed through Self-Assembly of Acyclic Cucurbit[n]uril for Targeted Drug Delivery to Cancer Cells

The supramolecular drug delivery systems (SDDSs) based on host-guest recognition through noncovalent interactions, capable of responsive behavior and dynamic switching to external stimuli, have attracted considerable attention in cancer therapy. In this study, a targeted dual-functional drug delivery system was designed and synthesized. A hydrophilic macrocyclic host molecule (acyclic cucurbit[n]uril ACB) was modified with folic acid (FA) as a targeting ligand. The guest molecule consists of a disulfide bond attached to adamantane (DA) and cannabidiol (CBD) at both ends of the response element of glutathione. Recognition and self-assembly of host and guest molecules successfully functionalize supramolecular nanomicelles (SNMs), targeting cancer cells and releasing drugs in a high glutathione environment. The interactions between host and guest molecules were investigated by using nuclear magnetic resonance (NMR), fluorescence titration, Fourier-transform infrared spectroscopy (FT-IR), and thermal analysis (TGA). Transmission electron microscopy (TEM) and dynamic light scattering (DLS) confirmed the nanostructure of the SNMs. Experimentation with 5,5'-dithiobis (2-nitrobenzoic acid) (DTNB) demonstrated the responsiveness of SNMs to glutathione (GSH). In vitro cytotoxicity assays demonstrated that SNMs had a greater targeting efficacy for four types of cancer cells (HeLa, HCT-116, A549, and HepG2) compared to normal 293T cells. Cellular uptake studies revealed that HeLa cells more readily absorbed SNMs, leading to their accumulation in the tumor cell cytoplasm. Fluorescence colocalization assays verified that SNMs efficiently accumulated in organelles related to energy metabolism and signaling, including mitochondria and the endoplasmic reticulum, affecting cellular metabolic death. Both flow cytometry and confocal nuclear staining assays confirmed that SNMs effectively induced apoptosis over time, ultimately resulting in the death of cancer cells. These findings demonstrate that SNMs exhibit excellent targeting ability, responsiveness, high bioavailability, and stability, suggesting significant potential in drug delivery applications.

Advances on Delivery System of Active Ingredients of Dried Toad Skin and Toad Venom

Dried toad skin (TS) and toad venom (TV) are the dried skin of the Bufo bufo gargarizans Cantor and the Bufo melanostictus Schneider, which remove the internal organs and the white secretions of the skin and retroauricular glands. Since 2005, cinobufacini preparations have been approved by the State Food and Drug Administration for use as adjuvant therapies in the treatment of various advanced cancers. Meanwhile, bufalenolides has been identified as the main component of TS/TV, exhibiting antitumor activity, inducing apoptosis of cancer cells and inhibiting cancer cell proliferation or metastasis through a variety of signaling pathways. However, clinical agents frequently face limitations such as inherent toxicity at high concentrations and insufficient tumor targeting. Additionally, the development and utilization of these active ingredients are hindered by poor water solubility, low bioavailability, and rapid clearance from the bloodstream. To address these challenges, the design of a targeted drug delivery system (TDDS) aims to enhance drug bioavailability, improve targeting within the body, increase drug efficacy, and reduce adverse reactions. This article reviews the TDDS for TS/TV, and their active components, including passive, active, and stimuli-responsive TDDS, to provide a reference for advancing their clinical development and use.

Mechanism of bufalin inhibition of colon cancer liver metastasis by regulating M2-type polarization of Kupffer cells induced by highly metastatic colon cancer cells

Patients with metastatic colorectal cancer often have poor outcomes, primarily due to hepatic metastasis. Colorectal cancer (CRC) cells have the ability to secrete cytokines and other molecules that can remodel the tumor microenvironment, facilitating the spread of cancer to the liver. Kupffer cells (KCs), which are macrophages in the liver, can be polarized to M2 type, thereby promoting the expression of adhesion molecules that aid in tumor metastasis. Our research has shown that huachanshu (with bufalin as the main active monomer) can effectively inhibit CRC metastasis. However, the underlying mechanism still needs to be thoroughly investigated. We have observed that highly metastatic CRC cells have a greater ability to induce M2-type polarization of Kupffer cells, leading to enhanced metastasis. Interestingly, we have found that inhibiting the expression of IL-6, which is highly expressed in the serum, can reverse this phenomenon. Notably, bufalin has been shown to attenuate the M2-type polarization of Kupffer cells induced by highly metastatic Colorectal cancer (mCRC) cells and down-regulate IL-6 expression, ultimately inhibiting tumor metastasis. In this project, our aim is to study how high mCRC cells induce M2-type polarization and how bufalin, via the SRC-3/IL-6 pathway, can inhibit CRC metastasis. This research will provide a theoretical foundation for understanding the anti-CRC effect of bufalin.

Bufalin for an innovative therapeutic approach against cancer

Bufalin is an endogenous cardiotonic steroid, first discovered in toad venom but also found in the plasma of healthy humans, with anti-tumour activities in different cancer types. The current review is focused on its mechanisms of action and highlights its very large spectrum of effects both in vitro and in vivo. All leads to the conclusion that bufalin mediates its effects by affecting all the hallmarks of cancer and seems restricted to cancer cells avoiding side effects. Bufalin decreases cancer cell proliferation by acting on the cell cycle and inducing different mechanisms of cell death including apoptosis, necroptosis, autophagy and senescence. Bufalin also moderates metastasis formation by blocking migration and invasion as well as angiogenesis and by inducing a phenotype switch towards differentiation and decreasing cancer cell stemness. Regarding its various mechanisms of action in cancer cells, bufalin blocks overactivated signalling pathways and modifies cell metabolism. Moreover, bufalin gained lately a huge interest in the field of drug resistance by both reversing various drug resistance mechanisms and affecting the immune microenvironment. Together, these data support bufalin as a quite promising new anti-cancer drug candidate.

Combined In Silico and Experimental Investigations of Resveratrol Encapsulation by Beta-Cyclodextrin

The results of the computational and the physicochemical studies of the encapsulation of resveratrol with β-cyclodextrin are presented here. At first, the molecular docking experiments predicted good binding. Several MD simulations and MM-PBSA experiments confirmed the reliable binding, showing optimal kinetics and energy. As an application, resveratrol inclusion complexes with β-cyclodextrin were obtained in an aqueous alcohol medium via microwave treatment. The results of thermographic measurements of the obtained clathrates using a differential scanning calorimeter are presented, and the obtained activation energy was calculated using the Ozawa–Flynn–Wall and Friedman methods, as well as nonparametric kinetics. The effect of complexation on the kinetic parameters of thermal destruction of the β-cyclodextrin–resveratrol inclusion complex was considered. The morphology of the surface of the obtained clathrate complexes was described using a scanning electron microscope. The spectral properties of the inclusion complex were characterized by FT-IR, 1H, and 13С NMR spectroscopic data. The obtained in silico, morphological, thermogravimetric, and spectral results confirmed the formation of the resveratrol–β-cyclodextrin complex. The antioxidant activities of the inclusion complex were determined to be 12.1 μg/mL, compared to 14.3 μg/mL for free resveratrol, indicating an improvement in the bioactivity.

A versatile enrichment of functionalized calixarene as a facile sensor for amino acids

Amino acids have become the most important part of the human biological system due to their roles in the living processes. Role of amino acids stretches beyond their traditional role as a building block for proteins, deficiency of the same could lead to decreased immunity, digestive problems, depression, fertility issues, lower mental alertness, slowed growth in children, and many other health issues. The acute detection of amino acids is necessary to determine the human health domain. Here in this review, we summarize and study the calixarenes as a complex detailed being of an immeasurable value and its utilization for the amino acids' detection. The key factors responsible such as noncovalent forces, LOD and supramolecular chemistry of calixarenes with amino acids are described well. This study presents the most recent efforts made for the development of potential and highly efficient calixarene based sensors for the detection of amino acids.

Novel Strategies for Solubility and Bioavailability Enhancement of Bufadienolides

Toad venom contains a large number of bufadienolides, which have a variety of pharmacological activities, including antitumor, cardiovascular, anti-inflammatory, analgesic and immunomodulatory effects. The strong antitumor effect of bufadienolides has attracted considerable attention in recent years, but the clinical application of bufadienolides is limited due to their low solubility and poor bioavailability. In order to overcome these shortcomings, many strategies have been explored, such as structural modification, solid dispersion, cyclodextrin inclusion, microemulsion and nanodrug delivery systems, etc. In this review, we have tried to summarize the pharmacological activities and structure-activity relationship of bufadienolides. Furthermore, the strategies for solubility and bioavailability enhancement of bufadienolides also are discussed. This review can provide a basis for further study on bufadienolides.

Obtaining and Investigation of the β-Cyclodextrin Inclusion Complex with Vitamin D 3 Oil Solution

Background. The research results of fat-soluble vitamin D 3 (cholecalciferol) encapsulation with β-cyclodextrin have been presented in this work. The vitamin D 3 inclusion complex with β-cyclodextrin was obtained under microwave radiation. The surface morphology of obtained clathrate inclusion complexes was described with the help of a scanning electron microscope. The thermographic measurement results on a differential scanning calorimeter have been presented. The activation energy of the β-cyclodextrin : vitamin D 3 clathrate complex thermal oxidative destruction reaction was calculated. The clathrate thermal destruction kinetic parameters were determined. The inclusion complex spectral properties were characterized by IR-Fourier and 1H and 13C NMR spectroscopy. The existence of β-cyclodextrin inclusion complex with vitamin D 3 in a 2 : 1 ratio was confirmed by the experimental results. The activation energy of thermal destruction of the inclusion complex of β-cyclodextrin with vitamin D 3 was calculated using four different methods.

Development of Pediatric Orodispersible Tablets Based on Efavirenz as a New Therapeutic Alternative

BACKGROUND

Efavirenz is the most used medication in the treatment of Acquired Immunodeficiency Syndrome (AIDS). The limited number of pediatric antiretroviral formulations approved by regulatory agencies is the most significant obstacle to adequate and efficient pharmacotherapy for this group of patients. The efavirenz has excellent therapeutic potential, but has low aqueous solubility/bioavailability.

METHODS

To minimize these limitations, multicomponent systems with β-cyclodextrin and polyvinylpyrrolidone K-30 were obtained. Due to the limited number of pediatric antiretroviral formulations, the development of a pediatric orodispersible tablet is an alternative that is thought easy to administer, since it disintegrates rapidly in the oral cavity. The multicomponent systems were obtained by the method of kneading and characterized by solubility test, X-ray diffraction, differential scanning calorimetry and infrared absorption spectroscopy by Fourier transform. The orodispersible tablets were prepared by direct compression. The quality control of hardness, friability, disintegration, and dissolution was performed. The influence of the components of the formulation on the characteristics of the tablets was evaluated through a 22 factorial design added with three central points, to compare the effect of the dependent variables on the responses.

RESULTS

An increase in drug solubility was observed, with a decrease in crystallinity. Besides that, an excellent dissolution profile presented with more than 83% of the drug's content dissolved in less than 15 minutes. Satisfactory disintegration time and friability were observed.

CONCLUSION

It was observed that reduced concentrations of mannitol decreased the hardness and disintegration time of the formulations. The orodispersible tablet composed of efavirenz: β- cyclodextrin: polyvinylpyrrolidone, favors greater absorption and bioavailability. It has several advantages for pediatric patients, as the dosage form disintegrates quickly in the mouth and does not require water for administration, thereby improving patient compliance with the treatment.

Preparation and Characterization of Octenyl Succinate β-Cyclodextrin and Vitamin E Inclusion Complex and Its Application in Emulsion

Vitamin E (VE) and β-cyclodextrin (β-CD) can form an inclusion complex; however, the inclusion rate is low because of the weak interaction between VE and β-CD. The results of a molecular docking study showed that the oxygen atom in the five-membered ring of octenyl succinic anhydride (OSA) formed a strong hydrogen bond interaction (1.89 Å) with the hydrogen atom in the hydroxyl group of C-6. Therefore, β-CD was modified using OSA to produce octenyl succinic-β-cyclodextrin (OCD). The inclusion complexes were then prepared using OCD with VE. The properties of the inclusion complex were investigated by Fourier-transform infrared spectroscopy (FT-IR), ¹³C CP/MAS NMR, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The results demonstrated that VE had been embedded into the cavity of OCD. Furthermore, the emulsifying properties (particle size distribution, ζ-potential, and creaming index) of the OCD/VE inclusion-complex-stabilized emulsion were compared with that stabilized by β-CD, OCD, and an OCD/VE physical mixture. The results showed that the introduction of the OS group and VE could improve the physical stability of the emulsion. In addition, the OCD/VE inclusion complex showed the strongest ability to protect the oil in the emulsion from oxidation. OCD/VE inclusion complex was able to improve the physical and oxidative stability of the emulsion, which is of great significance to the food industry.

New therapeutic aspects of steroidal cardiac glycosides: the anticancer properties of Huachansu and its main active constituent Bufalin

Aim of the review

In the past decade, increasing research attention investigated the novel therapeutic potential of steroidal cardiac glycosides in cancer treatment. Huachansu and its main active constituent Bufalin have been studied in vitro, in vivo and clinical studies. This review aims to summarize the multi-target and multi-pathway pharmacological effects of Bufalin and Huachansu in the last decade, with the aim of providing a more comprehensive view and highlighting the recently discovered molecular mechanisms.

Results

Huachansu and its major derivative, Bufalin, had been found to possess anti-cancer effects in a variety of cancer cell lines both in vitro and in vivo. The underlying anti-cancer molecular mechanisms mainly involved anti-proliferation, apoptosis induction, anti-metastasis, anti-angiogenesis, epithelial-mesenchymal transition inhibition, anti-inflammation, Na⁺/K⁺-ATPase activity targeting, the steroid receptor coactivator family inhibitions, etc. Moreover, the potential side-effects and toxicities of the toad extract, Huachansu, and Bufalin, including hematological, gastrointestinal, mucocutaneous and cardiovascular adverse reactions, were reported in animal studies and clinic trails.

Conclusions

Further research is needed to elucidate the potential drug-drug interactions and multi-target interaction of Bufalin and Huachansu. Large-scale clinical trials are warranted to translate the knowledge of the anticancer actions of Bufalin and Huachansu into clinical applications as effective and safe treatment options for cancer patients in the future.

Cyclodextrin-based delivery systems for cancer treatment

Cyclodextrins, one of safe excipients, are able to form host-guest complexes with fitted molecules given the unique nature imparted by their structure in result of a number of pharmaceutical applications. On the other hand, targeted or responsive materials are appealing therapeutic platforms for the development of next-generation precision medications. Meanwhile, cyclodextrin-based polymers or assemblies can condense DNA and RNA in result to be used as genetic therapeutic agents. Armed with a better understanding of various pharmaceutical mechanisms, especially for cancer treatment, researchers have made lots of works about cyclodextrin-based drug delivery systems in materials chemistry and pharmaceutical science. This Review highlights recent advances in cyclodextrin-based delivery systems for cancer treatment capable of targeting or responding to the physiological environment. Key design principles, challenges and future directions, including clinical translation, of cyclodextrin-based delivery systems are also discussed.

Optimization of β-cyclodextrin consolidated micellar dispersion for promoting the transcorneal permeation of a practically insoluble drug

Development of efficient ocular drug delivery system for antifungal drugs becomes a must nowadays to face and eradicate the widely spread ophthalmic fungal infections. Itraconazole, a triazole antifungal, is struggling to penetrate the cornea and subsequently, its efficacy is limited. The aim of this study was to enhance itraconazole corneal penetration through utilizing the minimum surfactant amount in presence of β-cyclodextrin which acted as a dissolution and permeation enhancer. β-Cyclodextrin consolidated micellar dispersions (CCMD) were prepared after an initial screening to select the composition of surfactant(s). The preparation was done according to a modified melt dispersion technique. The prepared CCMD were characterized through the analysis of their particle size, zeta potential and solubilization efficiency. The optimum formula was chosen based on a factorial response surface analysis and it was composed of 17:1 w/w surfactant/drug, 30:1 w/w cyclodextrin/drug ratios and 0.02% polyethylene oxide. This formula was subjected to in vitro characterization including release, imaging by transmission electron microscope, mucoadhesion, stability, in addition to the determination of the minimum inhibitory concentration. Moreover, the ex vivo/in vivo permeation, safety and efficacy profiles were determined. The optimized CCMD formula was found to be significantly safe, stable, mucoadhesive and efficient to permeate the drug through rabbits' corneas. Consequently, the optimized CCMD formulation can be a promising, safe and efficient platform for the transcorneal delivery of lipophilic drugs including most antifungals.

Increasing the anticancer performance of bufalin (BUF) by introducing an endosome-escaping polymer and tumor-targeting peptide in the design of a polymeric prodrug

A well-defined multifunctional brush-type polymeric prodrug covalently linked with an anticancer drug (bufalin, BUF), a tumor-targeting peptide (RGD), and an endosome-escaping polymer, poly(N,N-diethylaminoethyl methacrylate-co-butyl methacrylate (P(DEA-co-BMA)), was developed. Its anticancer performance against colon cancer was investigated in vitro and in vivo. Reversible addition-fragmentation transfer (RAFT) polymerization of oligo(ethylene glycol) monomethyl ether methacrylate (OEGMA), 2-((3-(tert-butoxy)-3-oxopropyl)thio)ethyl methacrylate (BSTMA), and 2-(2-bromoisobutyryloxy)ethylmethacrylate (BIEM) afforded the multifunctional random copolymer, P(OEGMA-co-BSTMA-co-BIEM), in which hydrophilic POEGMA can stabilize nanoparticles in water, PBSTMA can be converted into carboxyl groups, and PBIEM can be employed as a macromolecular atom radical transfer polymerization (ATRP) initiator. The ATRP of DEA and BMA using P(OEGMA-co-BSTMA-co-BIEM) as a macromolecular ATRP initiator led to the formation of the pH-responsive brush-type copolymer, P(OEGMA-co-BSTMA)-g-P(DEA-co- BMA). After hydrolysis by trifluoroacetic acid and post-functionalization the final polymeric prodrug, P(OEGMA-co-BUF-co-RGD)-g-P(DEA-co-BMA), was obtained with a drug content of ∼7.8 wt%. P(OEGMA-co-BUF-co-RGD)-g-P(DEA-co-BMA) can be assembled into nanoparticles (BUF- NP-RGD) in aqueous solution with a diameter of 148.4 ± 0.7 nm and a zeta potential of -7.6 ± 0.4 mV. BUF-NP-RGD exhibited controlled drug release in the presence of esterase. Additionally, P(OEGMA-co- BSMA)-g-P(DEA-co-BMA) showed a significant hemolysis effect at a pH comparable to that of endosomes/lysosomes. Cell viability and a tumor-bearing nude mouse model were employed to evaluate the anticancer efficacy of BUF-NP-RGD. It was revealed that BUF-NP-RGD showed improved anticancer performance compared with that of free BUF both in vitro and in vivo. Histological and immunochemical analysis further demonstrated that BUF-NP-RGD exhibited improved cell apoptosis, angiogenesis inhibition, and an anti-proliferation effect.