Scanning electron microscopy and atomic force microscopy imaging of solid lipid nanoparticles derived from amphiphilic cyclodextrins (original) (raw)
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Langmuir, 1998
Amphiphilic cyclodextrins bearing fatty acyl chains covalently linked to their secondary hydroxyl groups are able to form nanospheres with an internal organization. The structure of several cyclodextrins with different acyl chain lengths (CD-Cn) was investigated using X-ray scattering and freeze fracture electron microscopy. From the experimental data and using physicochemical arguments, we propose structure models. CD-C6, CD-C8, CD-C10, CD-C12, and γCD-C14 form polar columns, surrounded by the paraffin chains, and associated in a 2-D hexagonal lattice. The structure of RCD-C14 and CD-C14 is body-centered cubic; it comprises one lattice of dimers aligned along the edges of the cubic cell and a second identical lattice with a translation of the half in the three directions. This results in the formation of two globules, one at the apex and one at the center of the cell. The structures are unusual for cyclodextrin molecules; they result from the presence of the numerous paraffin chains linked to each molecule. Indeed, the structures are reminiscent of those found in lipid systems.
International Journal of Pharmaceutics, 2017
This work aimed at preparing new nanoscale assemblies based on an amphiphilic bio-esterified -cyclodextrin (-CD), substituted at the secondary face with n-decanoic fatty acid chains (-CD-C10), and monoolein (MO) as new carriers for parenteral drug delivery. Stable binary (-CD-C10/MO) and ternary (-CD-C10/MO/stabilizer) nanoscale assemblies close to 100 nm in size were successfully prepared in water by the solvent displacement method. The generated nanoparticles were fully characterized by dynamic light scattering, transmission electron microscopy, small-angle X-ray scattering, residual solvent analysis, complement activation and the contribution of each formulation parameter was determined by principal component analysis. The -CD-C10 units were shown to self-organize into nanoparticles with a hexagonal supramolecular packing that was significantly modulated by the molar ratio of the constituents and the presence of a steric or electrostatic stabilizer (DOPE-PEG2000 or DOPA/POPA, respectively). Indeed, nanoparticles differing in morphology and in hexagonal lattice parameters were obtained while the coexistence of multiple mesophases was observed in some formulations, in particular for the -CD-C10/MO/DOPA and -CD-C10/MO/POPA systems. The mixed -CD-C10/MO/DOPE-PEG2000 nanoparticles (49:49:2 in mol%) appeared to be the most suitable for use as a drug delivery system since they contained a very low amount of residual solvent and showed a low level of complement C3 activation.
Journal of Colloid and Interface Science, 2002
Recently, new cyclodextrin derivatives were synthesized and shown to exhibit strong amphiphilic properties. In this paper, we study the action of these new amphiphilic cyclodextrins on phospholipids. Mixed phospholipid/cyclodextrin derivative films were prepared and studied using X-ray reflectivity for various phospholipid/cyclodextrin ratios. A molar ratio of 3 provides a highly stable film the molecular structure of which has been investigated in detail. The cholesterol tail of the cyclodextrin molecule was found to be anchored into the phospholipid film. The cyclodextrin moieties exposed to the aqueous medium are prone to the addition of the guest molecule Dosulepin, making them of high interest for drug delivery. For this purpose and as an example of a potential application, this cyclodextrin molecular carrier property is also addressed to this complex film architecture. C 2002 Elsevier Science (USA)
Biofunctionalization of β-cyclodextrin nanosponges using cholesterol
Carbohydrate polymers, 2018
Cyclodextrins nanosponges (CD-NSPs) are highly microporous crosslinked polymers with potential applications in the delivery of small and macro-molecular therapeutic agents. Despite the potent host-guest inclusion property, their inherent lack of cellular binding ability has limited applications in drug delivery. Herein, we functionalized the surface of β-cyclodextrin nanosponge (β-CD-NSP) with cholesterol, which is endogenous physiological molecules, widely distributed in all cells, and responsible for cell interactions and protein binding. The surface grafting of synthesized β-CD-NSP was confirmed with spectroscopic, microscopic, thermogravimetric, and chromatographic techniques. Moreover, β-CD-NSP was found to be safe in cytotoxicity assay. Doxorubicin (Dox) was selected as a model drug for drug adsorption study of cholesterol hydrogen succinate (CHS) grafted β-CD-NSP. The cellular uptake of NSP was found to be enhanced after CHS modification confirmed by confocal laser scanning m...
Progress in Developing Amphiphilic Cyclodextrin-Based Nanodevices for Drug Delivery
Current Topics in Medicinal Chemistry, 2014
Nowadays, colloidal drug carriers represent an alternative to solve drug bioavailabily problems. During the past two decades, colloidal drug carriers have proved to improve the therapeutic index of drugs and thus increase their efficacy and/or reduce their toxicity. However, the major challenge in the development of these drug carriers remains the search for materials able to self-organize into stable nanoscale systems. In particular, amphiphilic- ,-and-cyclodextrins (CDs), grafted on their secondary or primary side with different aliphatic chains, have been investigated as drug delivery vehicles due to their ability to self-assemble and form various stable colloidal systems such as micellar aggregates, nanoreservoirs or nanoparticles exhibiting a matricial, multilamellar or hexagonal supramolecular organization. These self-assembled CD-based nanodevices show some advantages in terms of stability, good ability to associate lipophilic drugs and good in vivo tolerance. This review focuses on the potential of the structured nanoparticles obtained from nonionic amphiphilic CDs in drug delivery and targeting. We discuss the synthesis and characterization of the building blocks as well as the preparation and characterization of colloidal particles made from these materials. We also considered some pharmaceutical applications and identified opportunities for an optimum use of this CD-based nanotechnology approach in addressing worldwide priority health problems.
Journal of pharmaceutical sciences, 2016
Amphiphilic cyclodextrins (CDs) are biocompatible derivatives of natural CDs and are able to form nanoparticles or polyplexes spontaneously. In this study, nanoparticles prepared from nonionic (6OCaproβCD) or cationic amphiphilic CD (PC βCDC6) were used comparatively to develop nanoparticles intended for breast cancer therapy. The characterization of these nanoparticles was performed both by in vitro and cell culture studies. Furthermore, the apoptotic and cytotoxic effects of blank amphiphilic CDs were demonstrated by various mechanistic methods including Caspase-8 activity, lipid peroxidation assay, TUNEL assay, Tali(®)-based image analysis, cholesterol assay, and gene expression studies. Blank nanoparticles exerted cytotoxicity against a variety of cancer cells (MCF-7, HeLa, HepG2, and MB49) but none to healthy cells (L929, G/G). Interestingly, blank 6OCaproβCD and blank PC βCDC6 derivatives were found to be intrinsically effective on cell number and membrane integrity of MCF-7 c...
Nanoparticles derived from amphiphilic γ-cyclodextrins
Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2007
Three alkylcarbonates of c-cyclodextrin, i.e. hexyl, octyl and dodecylcarbonate, were synthesized and characterized, with the goal of formulating solid nanoparticles. The series of alkylcarbonates showed amphiphilic properties and were capable of forming micelles and nanoparticles. Blank and drug-loaded alkylcarbonate nanoparticles were prepared with each alkylcarbonate, using the solvent injection technique. Progesterone was chosen as model drug. The sizes of both unloaded and loaded nanoparticles were in the 80-200 nm range, with narrow size distribution and spherical shape, as shown by TEM analysis.The zeta potentials of unloaded nanoparticles were in the-20 to-24.0 mV range, and were slightly decreased in loaded nanoparticles. Drug-loading capacity was good; DSC analysis did not detect the progesterone melting peak, indicating the drug had interacted with the cyclodextrin alkylcarbonates. In vitro release kinetics of progesterone from the three types of nanoparticles were slow. These results indicate that c-CD alkylcarbonate nanoparticles might be used as prolonged drug delivery system.
Biomacromolecules, 2006
The synthesis of decanoate -cyclodextrin esters ( -CDd) and hexanoate -cyclodextrin esters ( -CDh) was biocatalyzed by thermolysin from native -cyclodextrin ( -CD) and vinyl hexanoate or vinyl decanoate used as acyl donors. The products were chemically characterized by infrared, NMR, and mass spectrometry. Both -CDd and -CDh esters were identified as a mixture of -CD preferentially substituted on the C2 position by the corresponding acyl chain. The degree of substitution varied from 2 to 7 for -CDd and from 4 to 8 for -CDh. The ability of -CD esters to self-organize into nanoparticles was tested using a nanoprecipitation technique in various solvents. The mean size diameter and polydispersity measured by quasi-elastic light scattering were dramatically affected by the nature of solvent (acetone, ethanol, or tetrahydrofuran) used in the nanoprecipitation technique. When directly observed using cryo-transmission electron microscopy, -CDh appeared as uniformly dense nanospheres, whereas -CDd exhibited a multilamellar onion-like organization. A structural model was rationalized for the -CDd nanoparticles.
Spontaneous formation of drug-containing amphiphilic β-cyclodextrin nanocapsules
International Journal of Pharmaceutics
A new colloidal carrier system, nanocapsules, using 2,3-diacyl-O-fl-cyclodextrins is described. The nanocapsules were prepared by adding a mixture of an organic solution of 2,3-diacyl-O-fl-cyclodextrins (with or without a lipophilic surfactant) and an oily phase to an aqueous solution (with or without a hydrophilic surfactant) whilst stirring. Nanocapsules with a mean size of 200 nm are formed progressively. Direct microscopic observation of the particles was carried out using transmission electron microscopy (TEM) combined with the freeze-fracture method. The influence of different constituents on the preparation process was studied: type of 2,3-diacyl-O-fl-cyclodextrins (fl-CD-C6,//-CD-Cj2 and fl-CD-CI4), nature of the oily phase (benzyl benzoate, Miglyol 812~), and the surfactants used (Pluronic PEF68 ®, Span 85"). An investigation of lipophilic drug encapsulation was also carried out. The results of this study suggest that nanocapsules of 2,3-diacyl-O-fl-cyclodextrins could be considered as a potential colloidal drug carrier system.