Preparation of gamma cyclodextrin stabilized solid lipid nanoparticles (SLNS) using stearic acid–γ-cyclodextrin inclusion complex

The application of cyclodextrins in drug solubilization and stabilization of nanoparticles for drug delivery and biomedical applications

Nanoparticles (NPs) have gained significant attention in recent years due to their potential applications in pharmaceutical formulations, drug delivery systems, and various biomedical fields. The versatility of colloidal NPs, including their ability to be tailored with various components and synthesis methods, enables drug delivery systems to achieve controlled release patterns, improved solubility, and increased bioavailability. The review discusses various types of NPs, such as nanocrystals, lipid-based NPs, and inorganic NPs (i.e., gold, silver, magnetic NPs), each offering unique advantages for drug delivery. Despite the promising potential of NPs, challenges such as physical instability and the need for surface stabilization remain. Strategies to overcome these challenges include the use of surfactants, polymers, and cyclodextrins (CDs). This review highlights the role of CDs in stabilizing colloidal NPs and enhancing drug solubility. The combination of CDs with NPs presents a synergistic approach that enhances drug delivery and broadens the range of biomedical applications. Additionally, the potential of CDs to enhance the stability and therapeutic efficacy of colloidal NPs, making them promising candidates for advanced drug delivery systems, is comprehensively reviewed.

Formation of Aggregate-Free Gold Nanoparticles in the Cyclodextrin-Tetrachloroaurate System Follows Finke-Watzky Kinetics

Cyclodextrin-capped gold nanoparticles are promising drug-delivery vehicles, but the technique of their preparation without trace amounts of aggregates is still lacking, and the size-manipulation possibility is very limited. In the present study, gold nanoparticles were synthesized by means of 0.1% (w/w) tetrachloroauric acid reduction with cyclodextrins at room temperature, at cyclodextrin concentrations of 0.001 M, 0.002 M and 0.004 M, and pH values of 11, 11.5 and 12. The synthesized nanoparticles were characterized by dynamic light scattering in both back-scattering and forward-scattering modes, spectrophotometry, X-ray photoelectron spectroscopy, transmission electron microscopy and Fourier-transform infrared spectroscopy. These techniques revealed 14.9% Au1+ on their surfaces. The Finke-Watzky kinetics of the reaction was demonstrated, but the actual growth mechanism turned out to be multistage. The synthesis kinetics and the resulting particle-size distribution were pH-dependent. The reaction and centrifugation conditions for the recovery of aggregate-free nanoparticles with different size distributions were determined. The absorbances of the best preparations were 7.6 for α-cyclodextrin, 8.9 for β-cyclodextrin and 7.5 for γ-cyclodextrin. Particle-size distribution by intensity was indicative of the complete absence of aggregates. The resulting preparations were ready to use without the need for concentration, filtration, or further purification. The synthesis meets the requirements of green chemistry.

Lipid Nanoparticle Technology for Delivering Biologically Active Fatty Acids and Monoglycerides

There is enormous interest in utilizing biologically active fatty acids and monoglycerides to treat phospholipid membrane-related medical diseases, especially with the global health importance of membrane-enveloped viruses and bacteria. However, it is difficult to practically deliver lipophilic fatty acids and monoglycerides for therapeutic applications, which has led to the emergence of lipid nanoparticle platforms that support molecular encapsulation and functional presentation. Herein, we introduce various classes of lipid nanoparticle technology and critically examine the latest progress in utilizing lipid nanoparticles to deliver fatty acids and monoglycerides in order to treat medical diseases related to infectious pathogens, cancer, and inflammation. Particular emphasis is placed on understanding how nanoparticle structure is related to biological function in terms of mechanism, potency, selectivity, and targeting. We also discuss translational opportunities and regulatory needs for utilizing lipid nanoparticles to deliver fatty acids and monoglycerides, including unmet clinical opportunities.

Cyclodextrin-based Pickering emulsions: functional properties and drug delivery applications

Cyclodextrins (CDs) are biocompatible, cyclic oligosaccharides that are widely used in various industrial applications and have intriguing interfacial science properties. While CD molecules typically have low surface activity, they are capable of stabilizing emulsions by inclusion complexation of oil-phase components at the oil/water interface, which results in Pickering emulsion formation. Such surfactant-free formulations have gained considerable attention in recent years, owing to their enhanced physical stability, improved tolerability, and superior environmental compatibility compared to conventional, surfactant-based emulsions. In this review, we critically describe the latest insights into the molecular mechanisms involved in CD stabilization of Pickering emulsions, including covering practical aspects such as methods to prepare CD-based Pickering emulsions, lipid encapsulation, and relevant stability issues. In addition, the rheological and textural features of CD-based Pickering emulsions are discussed and particular attention is focused on promising examples for drug delivery, cosmetic, and nutraceutical applications. The functionality of currently developed CD-based Pickering emulsions is also summarised, including examples such as antifungal uses, and we close by discussing emerging possibilities to utilize the molecular encapsulation of CD-based emulsions for translational medicine applications in the antiviral and antibacterial spaces.

In-Depth Study of Cyclodextrin Complexation with Carotenoids toward the Formation of Enhanced Delivery Systems

The goal of this study was molecular modeling of cyclodextrin (CD) and carotenoid complex formation. Distinction was made between complexes resulting from interactions between carotenoids and either molecularly dispersed CDs or solid crystalline CDs, considering that both cases can occur depending on the complex formation process pathways. First, the formation of complexes from dispersed CD molecules was investigated considering five different CDs (αCD, βCD, methyl-βCD, hydroxypropyl-βCD, and γCD) and lutein, as a model carotenoid molecule. The interactions involved and the stability of the different complexes formed were evaluated according to the CD size and steric hindrance. Second, the formation of complexes between four different crystalline CDs (βCD with three different water contents and methyl-βCD) and three carotenoid molecules (lutein, lycopene, and β-carotene) was studied. The docking/adsorption of the carotenoid molecules was modeled on the different faces of the CD crystals. The findings highlight that all the CD faces, and thus their growth rates, were equally impacted by the adsorption of the carotenoids. This is due to the fact that all the CD faces are exhibiting similar chemical compositions, the three studied carotenoid molecules are rather chemically similar, and last, the water-carotenoid interactions appear to be weak compared to the CD-carotenoid interactions.

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.