Self assembly in an aqueous gemini surfactant containing sugar based (isosorbide) spacer

Synthesis and in vitro evaluation of self-assembling biocompatible heparin-based targeting polymeric micelles for delivery of doxorubicin to leukemic cells

Background and purpose

Biodegradable polymeric micelles have emerged as one of the most promising platforms for targeted drug delivery. In the present study, a polymeric micelle composed of folic acid (FA), heparin (HEP), dexamethasone (DEX), and (FA-PEG-HEP-CA-TOC) was developed for the delivery of doxorubicin (DOX) to leukemic cells.

Experimental approach

FA-HEP-DEX was synthesized and characterized by 1H-NMR. DOX-loaded micelles were prepared using a dialysis method. The impact of various processing variables, including polymer-to-drug ratio, dialysis temperature, and solvent type, on the physicochemical properties of the micelles were evaluated. In vitro, cellular uptake and cytotoxicity of the micelles in folate receptor-positive (K562) and negative (HepG2) cells were evaluated.

Findings/Results

The 1H-NMR results confirmed the successful synthesis of FA-HEP-DEX. DOX-loaded micelles exhibited an average particle size of 117 to 181 nm with a high drug entrapment efficiency (36% to 71%). DOX-loaded micelles also showed sustained drug-release behavior. DOX-loaded FA-HEP-DEX micelles exhibited higher cellular uptake and in vitro cytotoxicity than free DOX and DOX-loaded HEP-DEX micelles in K562 cells.

Conclusions and implications

DOX was well incorporated into the micelles with high entrapment efficiency due to high solubility of DOX in DEX as the hydrophobic component of the micelle structure. The higher cellular uptake and cell toxicity of targeted micelles correspond to the presence of FA on the micelle surface, which promotes cell internalization of the micelles viaspecific receptor-mediated endocytosis. Our results indicated the potential of DOX-loaded heparin-based micelles with desirable antitumor activity as a targeted drug delivery system in cancer therapy.

Oligomeric cationic Gemini surfactants: synthesis, surface activities and rheological properties as thickener

In this study, three oligomeric cationic Gemini surfactants (Ⅲ1, Ⅲ2, and Ⅲ3) were prepared from different major raw materials, including long-chain alkyl amine (dodecyl amine, tetradecyl amine or cetyl amine), formic acid, formaldehyde, diethyl amine hydrochloride and epichlorohydrin. The synthesis conditions for one of the three surfactants, bis-[2-hydroxy-3-(N,N-dimethyl-N-dodecyl)propyl]dipropylammonium chloride (Ⅲ1), were optimised by orthogonal experiments. The optimum synthesis conditions were: molar ratio of intermediate Ⅱ to intermediate Ⅰ1 = 1.0:2.2, reaction temperature = 85 °C and reaction time = 16 h. The structures of the three prepared compounds were characterised by FTIR and 1H NMR. Their thermal properties were evaluated by thermal gravimetric analysis (TGA). The Geminisurfactants prepared exhibited better surface active properties than conventional single chain cationic surfactants. With increasing carbon chain length from C12 to C16, both CMC and surface tension γ CMC decreased, while the viscosity of the thickening solution prepared with the synthesised oligomeric cationic Gemini surfactants as the main component increased. The optimum thickening formula was: 2.0 wt% Ⅲ3 + 0.8 wt% sodium salicylate (NaSal) + 0.6 wt% KCl. The viscosity of the optimum thickening formulation was 190.4 mPa s. Gemini oligomeric cationic surfactants could be used as thickeners in the production of fracturing fluids, flooding agents and drilling fluids for oil and gas production in oil fields.

Gemini and Bicephalous Surfactants: A Review on Their Synthesis, Micelle Formation, and Uses

The use of surfactants in polymerization reactions is particularly important, mainly in emulsion polymerizations. Further, micelles from biocompatible surfactants find use in pharmaceutical dosage forms. This paper reviews recent developments in the synthesis of novel gemini and bicephalous surfactants, micelle formation, and their applications in polymer and nanoparticle synthesis, oil recovery, catalysis, corrosion, protein binding, and biomedical area, particularly in drug delivery.

Self-Assembly of Amphiphilic Compounds as a Versatile Tool for Construction of Nanoscale Drug Carriers

This review focuses on synthetic and natural amphiphilic systems prepared from straight-chain and macrocyclic compounds capable of self-assembly with the formation of nanoscale aggregates of different morphology and their application as drug carriers. Since numerous biological species (lipid membrane, bacterial cell wall, mucous membrane, corneal epithelium, biopolymers, e.g., proteins, nucleic acids) bear negatively charged fragments, much attention is paid to cationic carriers providing high affinity for encapsulated drugs to targeted cells. First part of the review is devoted to self-assembling and functional properties of surfactant systems, with special attention focusing on cationic amphiphiles, including those bearing natural or cleavable fragments. Further, lipid formulations, especially liposomes, are discussed in terms of their fabrication and application for intracellular drug delivery. This section highlights several features of these carriers, including noncovalent modification of lipid formulations by cationic surfactants, pH-responsive properties, endosomal escape, etc. Third part of the review deals with nanocarriers based on macrocyclic compounds, with such important characteristics as mucoadhesive properties emphasized. In this section, different combinations of cyclodextrin platform conjugated with polymers is considered as drug delivery systems with synergetic effect that improves solubility, targeting and biocompatibility of formulations.

Controllable assembly of a novel cationic gemini surfactant containing a naphthalene and amide spacer with β-cyclodextrin

A novel cationic gemini surfactant (C12NDDA) with a spacer containing naphthalene and amides was successfully synthesized. The assembly of C12NDDA with β-cyclodextrin (β-CD) was investigated using various techniques including transmission electron microscopy, proton nuclear magnetic resonance (1H NMR), and scanning electron microscopy. Tuning the C12NDDA concentration and the C12NDDA/β-CD molar ratio allowed the production of different assembled aggregate morphologies such as micelles, vesicles, nanowires, nanorods, and hydrogels. Investigation of the inclusion mechanisms of C12NDDA and β-CD by 1H NMR revealed that hydrophobic interactions, hydrogen bonding, π-π stacking, and electrostatic forces play key roles in the assembly process. The antimicrobial activities of the C12NDDA/xβ-CD (x = 0-4) inclusion complexes were tested against Gram-negative bacteria (Escherichia coli and Salmonella) and Gram-positive bacteria (Staphylococcus aureus and Streptococcus), and very low minimum inhibitory concentrations of 0.078-0.31 μg mL-1 were observed. Thus, this newly synthesized gemini surfactant and its inclusion complexes exhibit potential as superior broad-spectrum disinfectants for various biomedical and biotechnological applications.