In this study, Neem oil (NO) was extracted from the seeds of Azadirachta indica as a natural miticide agent. To prolong the insecticidal activity and control the sustainable release, various concentrations of NO were encapsulated in poly(D, L-lactic-co-glycolic) acid (PLGA) copolymers and high and low molecular weight (Mw) polyvinyl alcohol (PVAH and PVAL) microparticles (MPs) using the single and double emulsion solvent evaporation method. The effects of different parameters, such as the molecular weight of the stabilizing agent (PVA), stirring time, and polymer concentrations, on the size, stability, morphology, encapsulation efficiency, and release kinetics of the MPs were investigated. The presence of NO in PLGA/PVA MPs was confirmed by a shift in the glass transition temperature (T_g) to lower temperatures in the DSC thermograph, the appearance of peaks at 2854 cm⁻¹ in the FTIR spectrum, a peak at 205 nm in the UV–vis spectrum and a rough surface in SEM. Moreover, the release kinetics of the MPs demonstrated sustained release of NO over 48 h. In terms of MPs storage, temperature affected short-term stability, while long-term stability after one year in a dark environment at room temperature was confirmed by the particles' strength. The miticide assay on dust mites Dermatophagoides pteronyssinus revealed that MPs with the highest NO concentration (PLGA/PVAL/NO 65%) exhibited the most effective miticidal activity, achieving a 100% kill rate after 24 h. Finally, the colloidal dispersion and stability of the MPs over time were assessed using rheology, and the results confirmed the particles' spray ability for miticide application.

在这项研究中，印楝油 (NO) 从印楝种子中提取，作为天然杀螨剂。为了延长杀虫活性并控制持续释放，将不同浓度的 NO 包封在聚（D，L-乳酸-共-乙醇酸 (PLGA) 共聚物和高和低分子量 (Mw) 聚乙烯醇 (PVAH 和 PVAL) 微粒 (MPs) 使用单乳液和双乳液溶剂蒸发法。研究了稳定剂 (PVA) 的分子量、搅拌时间和聚合物浓度等不同参数对 MP 的尺寸、稳定性、形态、包封效率和释放动力学的影响。_{PLGA/PVA MPs 中 NO 的存在通过 DSC 温度记录仪中玻璃化转变温度 (T g} ) 向较低温度的转变、在 2854 cm ^-1处出现峰得到证实在 FTIR 光谱中，在 UV-vis 光谱中有一个 205 nm 的峰，在 SEM 中有一个粗糙的表面。此外，MP 的释放动力学表明 NO 的持续释放超过 48 小时。在 MPs 储存方面，温度影响短期稳定性，而在室温黑暗环境中一年后的长期稳定性由颗粒强度证实。对屋尘螨尘螨进行的杀螨试验表明，NO 浓度最高的 MPs (PLGA/PVAL/NO 65%) 表现出最有效的杀螨活性，24 小时后达到 100% 的杀灭率。最后，使用流变学评估了 MP 随时间的胶体分散和稳定性，结果证实了颗粒用于杀螨剂应用的喷雾能力。