Pesticides as Microemulsion Formulations

2016

PLoS ONE

In our previous study, we have identified five antimicrobial small molecules via structure based design, which inhibit SecA of Candidatus Liberibacter asiaticus (Las). SecA is a critical protein translocase ATPase subunit and is involved in pre-protein translocation across and integration into the cellular membrane in bacteria. In this study, eleven compounds were identified using similarity search method based on the five lead SecA inhibitors identified previously. The identified SecA inhibitors have poor aqueous solubility. Thus a microemulsion master mix (MMX) was developed to address the solubility issue and for application of the antimicrobials. MMX consists of N-methyl-2-pyrrolidone and dimethyl sulfoxide as solvent and co-solvent, as well as polyoxyethylated castor oil, polyalkylene glycol, and polyoxyethylene tridecyl ether phosphate as surfactants. MMX has significantly improved the solubility of SecA inhibitors and has no or little phytotoxic effects at concentrations less than 5.0% (v/v). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the SecA inhibitors and streptomycin against eight bacteria including Agrobacterium tumefaciens, Liberibacter crescens, Rhizobium etli, Bradyrhizobium japonicum, Mesorhizobium loti, and Sinorhizobium meliloti phylogenetically related to Las were determined using the broth microdilution method. MIC and MBC results showed that the 16 SecA inhibitors have antibacterial activities comparable to that of streptomycin. Overall, we have identified 11 potent SecA inhibitors using similarity search method. We have developed a microemulsion formulation for SecA inhibitors which improved the antimicrobial activities of SecA inhibitors.

Section: Introductionmentioning

confidence: 99%

Development of a Microemulsion Formulation for Antimicrobial SecA Inhibitors

Akula

2016

PLoS ONE

“…[1] Since traditional pesticide formulation such as emulsifiable concentrate based on organic solvent are gradually eliminated, water-based pesticide formulations such as suspension concentrates, microemulsion, nanoemulsion and nanosuspensions, have drawn growing attention in recent years. [2] Among these new generation formulations, microemulsion has some unique advantages such as thermodynamically stable, low energy input for preparation and fully water dilutable. The droplet size of the dispersed phase in the transparent microemulsion system is usually very small, typically below 100 nm in diameter.…”

Section: Introductionmentioning

confidence: 99%

“…[3] Pesticides active ingredients such as beta-cypermethrin, chlorpyriphos, and lambda cyhalothrin have all been prepared as microemulsion formulations. [2,4,5] Microemulsions are mixtures of two immiscible fluids (oil and water phase) that are made homogenous and transparent by the addition of surfactant. [6] Usually, cosurfactants such as short chain alcohols are also added to adjust the interfacial film by co-adsorption with surfactant molecules at oil/water interface.…”

Section: Introductionmentioning

confidence: 99%

Formulation and physicochemical properties of promising avermectin microemulsion with biodegradable surfactant and oil

Journal of Dispersion Science and Technology

Tai

et al. 2016

Green microemulsion suitable for oil-soluble pesticide delivery has been prepared using butyl acetate as oil phase, alkyl polyglycoside (APG) and linear alkylbenzene sulfonate (LAS) as mixed surfactant, and short chain alcohol as cosurfactant. Pseudoternary phase diagrams were constructed to investigate the effects of APG and LAS mixing ratio, the chain length of the cosurfactant on the microemulsion phase behavior. A fully dilutable region run through the phase diagram can be observed and the structure of the microemulsion transformed from water-in-oil, bicontinuous to oil-in-water along with the addition of water according to the result of conductivity measurement. Based on the phase diagram, the avermectin microemulsion formulations were chosen from the fully dilutable line with the minimum surfactant to oil ratio. Dilution stability of the microemulsion with hard water was studied by dynamic light scattering (DLS), the microemulsion can maintain the uniform and homogeneous appearance although the droplet size increased after dilution. The diluted microemulsion were also studied by dynamic surface tension and dynamic contact angle, and the excellent wetting and spreading properties on hydrophobic surface was demonstrated. GRAPHICAL ABSTRACTDownloaded by [University of Regina] at 02:08

“…However, most of pesticide compounds are generally poorly soluble in water which is not benefit to maintain bioactivity and increase efficacy and safety of the active ingredients after spraying [3]. The conventional pesticide formulations generally involve emulsifiable concentrate (EC), microemulsion (ME), suspension concentrate (SC), wettable powder (WP), and water dispersible granule (WDG) [4,5].…”

Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of Emamectin Benzoate Solid Nanodispersion

Yang

Cui

Journal of Nanomaterials

et al. 2017

The solid nanodispersion of 15% emamectin benzoate was prepared by the method of solidifying nanoemulsion. The mean particle size and polydispersity index of the solid nanodispersions were 96.6 ± 1.7 nm and 0.352 ± 0.041, respectively. The high zeta potential value of 31.3 ± 0.5 mV and stable crystalline state of the nanoparticles suggested the excellent physical and chemical stabilities. The contact angle and retention compared with microemulsions and water dispersible granules on rice, cabbage, and cucumber leaves indicated its improved wettability and adhesion properties. The bioassay compared with microemulsions and water dispersible granules against diamondback moths and green peach aphids provided an evidence of its enhanced biological activity. This formulation composition could avoid organic solvents and obviously reduce surfactants. It is perspective in raising bioavailability and reducing residual pollution of pesticides and further improving agricultural production and environmental safety.