Spontaneous nano-emulsification with tailor-made amphiphilic polymers and related monomers

In general, nano-emulsions are submicron droplets composed of liquid oil phase dispersed in liquid aqueous bulk phase. They are stable and very powerful systems when it regards the encapsulation of lipophilic compounds and their dispersion in aqueous medium. On the other hand, when the properties of the nano-emulsions aim to be modified, e.g. for changing their surface properties, decorating the droplets with targeting ligands, or modifying the surface charge, the dynamic liquid / liquid interfaces make it relatively challenging. In this study, we have explored the development of nano-emulsions which were not anymore stabilized with a classical low-molecular weight surfactant, but instead, with an amphiphilic polymer based on poly(maleic anhydride-alt-1-octadecene) (PMAO) and Jeffamine®, a hydrophilic amino-terminated PPG/PEG copolymer. Using a polymer as stabilizer is a potential solution for the nano-emulsion functionalization, ensuring the droplet stabilization as well as being a platform for the droplet decoration with ligands (for instance after addition of function groups in the terminations of the chains). The main idea of the present work was to understand if the spontaneous emulsification –commonly performed with nonionic surfactants– can be transposed with amphiphilic polymers, and a secondary objective was to identify the main parameters impacting on the process. PMAO was modified with two different Jeffamine®, additionally different oils and different formulation conditions were evaluated. As a control, the parent monomer, octadecyl succinic anhydride (OSA) was also modified and studied in the similar way as that of polymer. The generated nano-emulsions were mainly studied by dynamic light scattering and electron microscopy, that allows discriminating the crucial parameters in the spontaneous process, originally conducted with polymers as only stabilizer.

Download Full-text

Studies of Spontaneous Emulsification. II. The Effect of Nonionic Surfactants

Bulletin of the Chemical Society of Japan ◽

10.1246/bcsj.49.1187 ◽

1976 ◽

Vol 49 (5) ◽

pp. 1187-1190 ◽

Cited By ~ 11

Author(s):

Keizo Ogino ◽

Motoki Ota

Keyword(s):

Nonionic Surfactants ◽

Spontaneous Emulsification

Download Full-text

Modeling the interfacial tension dependence on composition and stiffness of nonionic surfactants on liquid–liquid interfaces

Colloids and Surfaces A Physicochemical and Engineering Aspects ◽

10.1016/j.colsurfa.2016.05.056 ◽

2017 ◽

Vol 519 ◽

pp. 168-178 ◽

Cited By ~ 3

Author(s):

Hristina Popova ◽

Andrey Milchev ◽

Sergei A. Egorov

Keyword(s):

Interfacial Tension ◽

Nonionic Surfactants ◽

Liquid Interfaces

Download Full-text

Characterization and Antibacterial Activity of Oil-In-Water Nano-Emulsion Formulation Against Candidatus Liberibacter asiaticus

Plant Disease ◽

10.1094/pdis-05-16-0600-re ◽

2016 ◽

Vol 100 (12) ◽

pp. 2448-2454 ◽

Cited By ~ 4

Author(s):

C. Y. Yang ◽

C. A. Powell ◽

Y. P. Duan ◽

M. Q. Zhang

Keyword(s):

Droplet Size ◽

Peak Concentration ◽

Candidatus Liberibacter Asiaticus ◽

Spontaneous Emulsification ◽

Therapeutic Efficiency ◽

Oil In Water ◽

Candidatus Liberibacter ◽

Emulsion Formulation ◽

Liberibacter Asiaticus ◽

Nano Emulsion

Nano-emulsion is a promising delivery system for increasing pesticide use and enhancing the therapeutic efficiency against pathogens. The pathogen Candidatus Liberibacter asiaticus (Las) that causes destructive citrus huanglongbing (HLB) resides in citrus phloem, which makes it difficult to treat with chemicals. Based on various physiochemical characteristics of oils, surfactants, and organic solvents, an oil-in-water (O/W) nano-emulsion formulation was developed and optimized to combat citrus HLB. The nano-emulsion was formulated through a spontaneous emulsification method for efficient delivery of ampicillin into the citrus phloem using bark application. The nano-emulsion that was prepared from Cremophor EL (viscous oil), acetone (water miscibility organic solvent), and Span 80/Tween 80 (surfactant) formed a small droplet size (17.33 ± 0.52 nm) and exhibited an improved absorption rate. Peak concentration was detected at 2 days posttreatment and the maximum concentration (Cmax) and relative bioavailability (RBA) of ampicillin in HLB-affected citrus were 71.86 ± 35.38 ng/g and 267.25% ± 44.1%, respectively. The peak concentration of Amp appeared at 6 days posttreatment in the citrus trees that were treated with Amp alone and their Cmax and RBA were 56.44 ± 32.59 ng/g and 100%, respectively. The same nano-emulsion was used to deliver five different antimicrobials to control citrus HLB through bark application. We found that the droplet size of the antimicrobials in the nano-emulsion was significantly reduced and the nano-emulsion also enhanced the therapeutic efficiency of validoxylamine A alone and in combination with actidione as well as sulfadimoethoxine sodium against Las. Therefore, this study provides an efficient bark application nano-emulsion formulation for citrus HLB control.

Download Full-text

Water-in-Oil Nano-Emulsions Prepared by Spontaneous Emulsification: New Insights on the Formulation Process

Pharmaceutics ◽

10.3390/pharmaceutics13071030 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1030

Author(s):

Salman Akram ◽

Nicolas Anton ◽

Ziad Omran ◽

Thierry Vandamme

Keyword(s):

Volume Fraction ◽

Scale Up ◽

Surface Modifications ◽

Yield Potential ◽

Dispersed Phase ◽

Spontaneous Emulsification ◽

Oil In Water ◽

Mixing Rates ◽

Formulation Parameters ◽

Nano Emulsion

Nano-emulsions consist of stable suspensions of nano-scaled droplets that have huge loading capacities and are formulated with safe compounds. For these reasons, a large number of studies have described the potential uses of nano-emulsions, focusing on various aspects such as formulation processes, loading capabilities, and surface modifications. These studies typically concern direct nano-emulsions (i.e., oil-in-water), whereas studies on reverse nano-emulsions (i.e., water-in-oil) remain anecdotal. However, reverse nano-emulsion technology is very promising (e.g., as an alternative to liposome technology) for the development of drug delivery systems that encapsulate hydrophilic compounds within double droplets. The spontaneous emulsification process has the added advantages of optimization of the energetic yield, potential for industrial scale-up, improved loading capabilities, and preservation of fragile compounds targeted for encapsulation. In this study, we propose a detailed investigation of the processes and formulation parameters involved in the spontaneous nano-emulsification that produces water-in-oil nano-emulsions. The following details were addressed: (i) the order of mixing of the different compounds (method A and method B), (ii) mixing rates, (iii) amount of surfactants, (iv) type and mixture of surfactants, (v) amount of dispersed phase, and (vi) influence of the nature of the oil. The results emphasized the effects of the formulation parameters (e.g., the volume fraction of the dispersed phase, nature or concentration of surfactant, or nature of the oil) on the nature and properties of the nano-emulsions formed.

Download Full-text