Ethanol effects on the gelation behavior of α-tocopherol acetate-encapsulated ethosomes with water-soluble polymers

Abstract

This work aims at understanding the ethanol effects on the gelation behavior of ethosomes with the consideration of encapsulating a hydrophobic material. Gelation of the empty ethosomes by positively charged watersoluble polymers with and without hydrophobic modification, respectively, was systematically studied first for the effects of solution dielectric constant and gelator concentration on the phase map and rheological property of the mixtures. A comparison of the gelation behavior of empty and α-tocopherol acetate (α-TA)-encapsulated ethosomes sheds light on the possible influence of encapsulated hydrophobic material itself on the interaction between ethosomal lipid bilayers and gelator molecules. The experimental results revealed that ethosomes with an optimized amount of ethanol could result in a reasonable lifetime and encapsulation efficiency of more than 90 %. This is due to the effects of the solution dielectric constant on the formability of liposome and the partition of the hydrophobic material (α-TA) between ethosomal lipid bilayer and bulk phase. Moreover, the phase map and rheological property of the ethosome/polymer mixtures were found to be affected by the configuration of the polymer chain in aqueous ethanol solution. That is, the driving interactions between ethosomal lipid bilayers and gelator molecules were dominated by the hydrophobic material more than the electrostatic association. Finally, inclusion of a hydrophobic material, such as α-TA, in the ethosomes had less influence on the gelation behavior of the ethosomes with water-soluble polymers.

Preparasi Salbutamol Sulfat dalam Pembawa Vesikuler Etosom

“…Hal ini sejalan dengan hasil yang diperoleh yaitu %EE maksimum terdapat pada formula C (etanol 40%) dan %EE minimum terdapat pada formula D (etanol 20%). Beberapa studi melaporkan bahwa konsentrasi optimal etanol dalam pengembangan sistem etosom yang stabil adalah sekitar 30-40% [28][29][30] . Perlu dicatat bahwa penggunaan etanol di atas 40% menyebabkan vesikel menjadi sangat permeabel sehingga dapat terjadi 'kebocoran' yang kemudian menurunkan nilai %EE 27 .…”

Liposomes with an Ethanol Fraction as an Application for Drug Delivery

“…A two-fold increase in ethanol concentration resulted in a yield decrease to 16 +/− 5.6%. It has been shown that increasing the alcohol concentration reduces the stiffness of the lipid particles [43]. Many other medicinal substances are enclosed in the ethosome including quercetin [44] and rutin [45].…”

Ethosomes: versatile vesicular carriers for efficient transdermal delivery of therapeutic agents

“…However, optimization of concentration of ethanol in ethosomal systems is somewhat obligatory in terms of vesicle size, entrapment efficiency, stability, safety, etc. A wide range of investigational studies have reported 30-40% as an optimal range of ethanol in the development of stable and successful ethosomes (Limsuwan & Amnuaikit, 2012;Chiu et al, 2013;Zhao et al, 2013). Studies have reported the increment in the size of vesicle by ethanol concentration range of 20-45% Elsayed et al, 2007) etc.…”