Development of chitosan nanocapsules for the controlled release of hexaconazole.

Accelerated use of pesticides in cutting edge agriculture prompted us to explore smart nanoformulations to subside the consumption of these perilous chemicals. Polymer nanocapsules carrying a fungicide, hexaconazole were developed through ionotropic gelation method utilizing chitosan and tripolyphosphate (TPP). The nanocapsules were characterized by photon correlation spectroscope (PCS), transmission electron microscope (TEM), and Fourier transform infra-red (FTIR) spectroscope. Nanocapsules were optimized for size and high encapsulation efficiency using central composite design (CCD) software. The encapsulation efficiency of nanocapsules for hexaconazole was 73% as assessed by gas chromatography (GC). Nanocapsules were analysed and compared with commercial formulation for controlled release in vitro at three different pH values. Release of hexaconazole from nanocapsules was fastest at pH 4 in comparison to pH 7 and pH 10. Release study in soil was also conducted and revealed a controlled pattern for nanoformulation. The fungicidal activity of the prepared nanoformulation was evaluated against R. solani and was compared with commercial formulation of hexaconazole. The cytotoxicity assay performed on vero cell lines by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) assay confirmed that nanoformulation is less toxic than commercial formulation of pesticide.

Effect of Nanohexaconazole on Nitrogen Fixing Blue Green Algae and Bacteria.

Nanohexaconazole is a highly efficient fungicide against Rhizoctonia solani. Nanoparticles are alleged to adversely affect the non-target organisms. In order to evaluate such concern, the present study was carried out to investigate the effect of nanohexaconazole and its commercial formulation on sensitive nitrogen fixing blue green algae (BGA) and bacteria. Various activities of algae and bacteria namely growth, N-fixation, N-assimilation, Indole acetic acid (IAA) production and phosphate solubilization were differently affected in the presence of hexaconazole. Although, there was stimulatory to slightly inhibitory effect on the growth measurable parameters of the organisms studied at the recommended dose of nanohexaconazole, but its higher dose was inhibitory to all these microorganisms. On the other hand, the recommended as well as higher dose of commercial hexaconazole showed much severe inhibition of growth and metabolic activity of these organisms as compared to the nano preparation. The uses of nanohexazconazole instead of hexaconazole as a fungicide will not only help to control various fungal pathogens but also sustain the growth and activity of these beneficial microorganisms for sustaining soil fertility and productivity.

Development and evaluation of alginate-chitosan nanocapsules for controlled release of acetamiprid.

Smart formulations based on nanomaterials have the capability to reduce the consumption of hazardous pesticides and their impact on human health and environment. Nanoformulations of agrochemicals have the potential to improve food productivity without compromising with the ecosystem. In the present work, controlled release nanocapsules containing acetamiprid were prepared by polyelectrolyte complexation of two natural macromolecules, i.e. alginate and chitosan. The size, morphology and chemical interaction studies of the prepared nanocapsules were investigated by Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), and Fourier Transform Infrared Spectroscopy (FTIR). The zetapotential studies revealed stability of the nanocapsules. TEM results show spherical morphology of the nanocapsules. The encapsulation efficiency was found to be 62% as quantified by Ultra High Pressure Liquid Chromatography (UHPLC). Nanocapsules were analysed for controlled release in vitro at three different pH. Maximum release was observed at pH 10 followed by pH 7 and 4, respectively. A non-Fickian release mechanism was found to be followed by the nanoformulation. A controlled release pattern was also found from nanoformulation as compared to commercial formulation in soil. Thus this formulation can reduce the frequency of application of pesticides by controlling the release and will subsequently reduce their side effects.