Gelation of ethosome-like catanionic vesicles by water-soluble polymers: ethanol and cholesterol effects

Abstract

Ethosome-like catanionic vesicles are vesicular carriers prepared by using ion-pair amphiphiles (IPAs) and relatively high concentrations of ethanol through a semispontaneous process for dermal drug delivery.In this work, the effects of ethanol and cholesterol on the polymer configuration and vesicular membrane rigidity (or hydrophobicity) and therefore the gelation of the as-prepared ethosome-like catanionic vesicles by water-soluble polycations with and without hydrophobic modification (HMP + and P + ), respectively, were systematically studied for the decyltrimethylammonium-dodecylsulfate (DeTMA-DS) IPA system. The experimental results revealed that the configuration of the polymer chain in aqueous ethanol solution may vary significantly with the dielectric constant of mixed solvents.Moreover, while the vesicular membrane rigidity of the ethosome-like catanionic vesicle was slightly deteriorated by ethanol, it was greatly enhanced by cholesterol. Phase maps and rheological properties of the mixtures of ethosome-like catanionic vesicles and polymers indicated that the interaction between vesicles and polymer HMP + decreases and increases with the increasing ethanol concentration and cholesterol content, respectively. Both ethanol concentration and cholesterol content, however, showed little effect on the interaction between vesicles and polymer P + . These findings lead to the conclusion that the gelation of ethosome-like catanionic vesicles by polymer molecules is driven by the hydrophobic more than the electrostatic interactions. Possible mechanisms of ethanol and cholesterol effects on gelation of the ethosome-like catanionic vesicles by the polycations were also proposed based on the experimental results.

Importance of Hydrophilic Groups on Modulating the Structural, Mechanical, and Interfacial Properties of Bilayers: A Comparative Molecular Dynamics Study of Phosphatidylcholine and Ion Pair Amphiphile Membranes

“…The stability can be improved inter-vesicular using additives such as charged amphiphiles or polymers that increase the electrostatic or steric repulsion among IPA vesicles [ 15 , 16 , 17 ]. Meanwhile, additives such as cholesterol have been shown to improve the intra-vesicular stability of IPA vesicles via strengthening the mechanical properties of the vesicular bilayer [ 18 , 19 , 20 , 21 , 22 ]. The vesicles prepared from biomimetic IPAs are therefore good candidates as phospholipid substitutes and have great potentials in various applications such as cosmetics and drug carriers [ 23 , 24 ].…”

Terbinafine hydrochloride loaded liposome film formulation for treatment of onychomycosis:in vitroandin vivoevaluation

“…By the way, film formulations cannot be obtained with ethosome suspensions. The effect of ethanol on gelation of ethosome was reported by Chiu et al (2013). It was concluded that, ethanol mainly affects the gelation through its influence on the solution dielectric constant and therefore the polymer chain configuration and for ethosomelike catanionic vesicles with higher ethanol concentrations; a larger amount of gelator is needed for the formation of a gel phase.…”

Effects of Sterol-Like Additives on Phase Transition Behavior of Ion-Pair Amphiphile Bilayers

“…The physical stability of catanionic vesicles could be significantly enhanced by the presence of CHOL in the vesicular bilayer structures 10,17,18 .…”

“…Moreover, while the increase in CHOL concentration resulted in increase in the encapsulation efficiency of a hydrophobic drug for DeTMA-DS decyltrimethylammoniumdodecylsulfate and DeTMA-TS decyltrimethylammoniumtetradecylsulfate, CH 3 CH 2 9 N CH 3 3 -CH 3 CH 2 13 SO 4 systems 17,18 , the increase in CHOL concentration resulted in decrease in the encapsulation efficiency of the same drug for dodecyltrimethylammonium-dodecylsulfate DTMA-DS, CH 3 CH 2 11 N CH 3 3 -CH 3 CH 2 11 SO 4 system 18 .…”