Enhancement of iodinin solubility by encapsulation into cyclodextrin nanoparticles

Phenazine is known to regroup planar nitrogen-containing heterocyclic compounds. It was used here to enhance the bioavailability of the biologically important compound iodinin, which is near insoluble in aqueous solutions. Its water solubility has led to the development of new formulations using diverse amphiphilic α-cyclodextrins (CDs). With the per-[6-desoxy-6-(3-perfluorohexylpropanethio)-2,3-di-O-methyl]-α-CD, we succeeded to get iodinin-loaded nanoformulations with good parameters such as a size of 97.9 nm, 62% encapsulation efficiency and efficient control release. The study presents an interesting alternative to optimizing the water solubility of iodinin by chemical modifications of iodinin.

Self-Assembled Supramolecular Nanoparticles Improve the Cytotoxic Efficacy of CK2 Inhibitor THN7

Since the approval of imatinib in 2001, kinase inhibitors have revolutionized cancer therapies. Inside this family of phosphotransferases, casein kinase 2 (CK2) is of great interest and numerous scaffolds have been investigated to design CK2 inhibitors. Recently, functionalized indeno[1,2-b]indoles have been revealed to have high potency against human cancer cell lines such as MCF-7 breast carcinoma and A-427 lung carcinoma. 4-Methoxy-5-isopropyl-5,6,7,8-tetrahydroindeno[1,2-b]indole-9,10-dione (THN7), identified as a potent inhibitor of CK2 (IC₅₀ = 71 nM), was selected for an encapsulation study in order to evaluate its antiproliferative activity as THN7-loaded cyclodextrin nanoparticles. Four α-cyclodextrins (α-CDs) were selected to encapsulate THN7 and all experiments indicated that the nanoencapsulation of this CK2 inhibitor in α-CDs was successful. No additional surface-active agent was used during the nanoformulation process. Nanoparticles formed between THN7 and α-C₆H₁₃ amphiphilic derivative gave the best results in terms of encapsulation rate (% of associated drug = 35%), with a stability constant (K₁₁) of 298 mol·L⁻¹ and a size of 132 nm. Hemolytic activity of the four α-CDs was determined before the in cellulo evaluation and the α-C₆H₁₃ derivative gave the lowest value of hemolytic potency (HC₅₀ = 1.93 mol·L⁻¹). Only the THN7-loaded cyclodextrin nanoparticles showing less toxicity on human erythrocytes (α-C₆H₁₃, α-C₈H₁₇ and α-C₄H₉) were tested against A-427 cells. All drug-loaded nanoparticles caused more cytotoxicity against A-427 cells than THN7 alone. Based on these results, the use of amphiphilic CD nanoparticles could be considered as a drug delivery system for indeno[1,2-b]indoles, allowing an optimized bioavailability and offering perspectives for the in vivo development of CK2 inhibitors.

pH and cation-responsive supramolecular gels formed by cyclodextrin amines in DMSO

Amine-modified cyclodextrins are capable of forming pH and cation-responsive organogels in DMSO at low molar fractions.

[Amphiphilic cyclodextrins and their applications. Preparation of nanoparticles based on amphiphilic cyclodextrins for biomedical applications]

Solubilization of hydrophobic drugs at the molecular level as inclusion complexes inside cyclodextrins (CDs) offers a good alternative for improving their stability, solubility and bioavailability, and for preventing against their possible toxicity or controlling secondary effects. Therefore CDs are widely used as solubilizing excipients. However since dissociation takes place too readily upon dilution, inclusion complexes inside simple water-soluble CD appears ineffective for drug delivery applications. Chemical modifications of CDs allow them to self-organize as larger assemblies useful for resolving this lability issue. Depending on the position, the number and the nature of these groups, amphiphilic CDs can form assemblies such as vesicles, solid-lipid nanoparticles, nanospheres, liquid crystals, or micellar systems. This review deals with the synthesis of amphiphilic cyclodextrins leading to supramolecular assemblies and the physical properties of these assemblies. From the first sulfonated amphiphilic cyclodextrins isolated in our laboratory in 2003, to the latest ones being regioselectively functionalized by two or four fluoroalkyl chains, through the persubstituted fluorinated cyclodextrines, all these amphiphilic cyclodextrins have shown good abilities for encapsulation. Complexation of bioactive molecules (acyclovir) by these modified alpha-cyclodextrin derivatives, the encapsulation efficiency and release profile were measured as an assessment of the properties of such nanoparticles regarding drug delivery applications.

Novel nanoparticles made from amphiphilic perfluoroalkyl alpha-cyclodextrin derivatives: preparation, characterization and application to the transport of acyclovir

The preparation of aqueous suspensions of nanoparticles of the fluorinated amphiphilic alpha-cyclodextrins hexakis[6-deoxy-6-(3-perfluoroalkylpropanethio)-2,3-di-O-methyl]-alpha-cyclodextrin and their hydrocarbon analogues was studied. The complexation of acyclovir by modified alpha-cyclodextrin, the encapsulation efficiency and release profile were measured as an assessment of the properties of such nanoparticles regarding drug delivery applications. Stable aqueous suspensions of nanoparticles were prepared using nanoprecipitation method without using surface-active agent. The organic solvent (ethanol) and cyclodextrin concentration (0.4 mM) were carefully selected. The nanoparticles prepared from these new amphiphilic alpha-cyclodextrin derivatives according to optimized conditions have an average diameter of 100 nm for fluorinated derivatives and 150 nm for hydrocarbon analogues. Suspensions were stable over at least 9 months. Acyclovir forms inclusion complexes of 1:1 stoichiometry and high stability constants (from 700 mol L(-1) to 4000 mol L(-1) in ethanol) as assessed from UV/vis spectroscopy and Electrospray Ionization Mass Spectroscopy. Satisfactory loading of acyclovir inside the nanoparticles was achieved according to the "highly loaded" preparation method (encapsulation efficiency approximately 40%). Nanoparticles based on the fluorinated compounds delayed the drug release up to 3 h with little initial burst release. Fluorinated amphiphilic alpha-cyclodextrins self-assemble in the form of nanospheres that encapsulate acyclovir and allow sustained release, showing their potential for applications to drug delivery.