| Avermectin has become an alternative to highly toxic pesticides in agriculture because of its low toxicity,high efficiency,and high selectivity.However,in the actual application process,there are problems such as poor water solubility,poor photostability,and short duration of efficacy,which lead to a substantial increase in cost and limit the large-scale application in crop production.Therefore,improving the photostability of abamectin is conducive to its wide and efficient application in agriculture.Flash Nanoprecipitation(FNP)is a novel and rapid preparation of nanoparticles,which is often used to prepare polymer nanoparticles containing organic active substances.Lignin-based nanomaterials with green and abundant sources have attracted wide attention in many functional materials fields.On this basis,we used FNP technology to design and prepare a series of lignin-based nanoparticles with different structures.By adjusting the concentration,flow rate and solvent volume ratio,the particle size was controllable,and the infrared spectroscopy and transmission electron microscopy were performed on them.Characterization,stability,sustained release properties and resistance to photolysis were studied,and the specific studies are as follows:Lignin/AVM nanoparticles were prepared by FNP method.The nanoparticle structure,control conditions,sustained release properties,and resistance to photolysis were investigated.The experimental results show that the FNP method can control the particle size in the range of 50-180 nm by AVM concentration,flow rate,and solvent volume ratio.It can be stored at room temperature for 15 days and remains stable,the cumulative release rate of AVM within 191 h is less than 70%,and the photolysis resistance is improved by 10% compared with the original drug of AVM.Based on the previous experiments,the antioxidants BHT and TBHQ were added to further improve the resistance to photolysis.LN/AVM-BHT and LN/AVM-TBHQ nanoparticles were successfully prepared by FNP method.It was found that increasing the concentrations of BHT and TBHQ resulted in an increase in particle size nanoparticles,because increasing the concentration of antioxidants was equivalent to increasing the concentration of drug molecules.The LN/AVM-BHT-15 % NPs and LN/AVM-TBHQ-15%NPs with the antioxidant concentration of 15% AVM were prepared,and their average particle sizes were74.2 nm and 81.3 nm,respectively.After 50 h of UV light irradiation,the retention rates of avermectin were 57.3% and 41.4%,respectively,which were 20.8% and 11.7% higher than that of AVM original drug,respectively,and had high resistance to photolysis.Preparation of PFG-b-PLGA(5k-10k)/LN/AVM NPs by using lignin as drug-loading material,by adding amphiphilic polymers to form self-assembly and lignin to form a tighter structure and improve the stability of nanoparticles.With the addition of a small amount of in the case of PFG-b-PLGA(5k-10k),drug-loaded nanoparticles with an average particle size of 88.4 ± 2.3 nm can be obtained.After 15 days of room temperature storage experiments,the particle size and PDI remained basically unchanged;and the addition of PFG-b-PLGA(5k-10k)had a certain slowing effect on inhibiting the photodegradation of avermectin under ultraviolet light;after 191 h The cumulative release of AVM was 82.3%.Using calcium lignosulfonate and sodium phytate as drug-carrying materials and using the complexation of the two as the driving force to coat avermectin by FNP method,CL/AVM/SP with p H-responsive controlled release was prepared.NPs.After 15 days of room temperature storage experiments,the particle size of the nanoparticles with a particle size of 143 nm changed little,and the stability was better;Calcium lignosulfonate has a certain resistance to photolysis;CL/AVM/SP NPs showed different release rates under different p H conditions,while CL/AVM/SP NPs photodegraded avermectin under UV light There was a certain slowing effect,and the AVM in the nanoparticles reached 42.5% after50 h. |
PDF Full Text Request