Preparation and Characterization of Imidacloprid Lignin–Polyethylene Glycol Matrices Coated with Ethylcellulose

• Published in: Journal of agricultural and food chemistry 2012-02, Vol.60 (4), p.1042-1051
• Main Authors: Flores-Céspedes, Francisco, Figueredo-Flores, Cristina Isabel, Daza-Fernández, Isabel, Vidal-Peña, Fernando, Villafranca-Sánchez, Matilde, Fernández-Pérez, Manuel
• Format: Article
• Language: English
• Subjects: active ingredients; Biological and medical sciences; Cellulose - analogs & derivatives; Cellulose - chemistry; Chemical Phenomena; Delayed-Action Preparations - chemical synthesis; differential scanning calorimetry; Food industries; Fundamental and applied biological sciences. Psychology; imidacloprid; Imidazoles - administration & dosage; Imidazoles - adverse effects; Imidazoles - chemistry; infrared spectroscopy; Insecticides; Lignin - chemistry; Microscopy, Electron, Scanning; Neonicotinoids; Nitro Compounds - administration & dosage; Nitro Compounds - adverse effects; Nitro Compounds - chemistry; pollution; Polyethylene Glycols - chemistry; polymers; Polymers - chemistry; risk; scanning electron microscopy; Water - chemistry; Water Pollution, Chemical - prevention & control; water solubility
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf2037483

Imidacloprid, a systemic insecticide that has a water solubility of 610 mg L–1, has been formulated in lignin–polyethylene glycol matrices by a melting process. This formulation was coated in a Wurster type fluidized-bed equipment using ethylcellulose and dibutyl sebacate. Imidacloprid has been entrapped, with an entrapment efficiency higher than 87% in all cases. Thermogravimetric analysis, differential scanning calorimetry, and Fourier transformed infrared spectroscopy studies indicate the stability and compatibility of polymers and imidacloprid. Scanning electron microscopy images show a homogeneous film of ethylcellulose in coated formulations. From T 50 values (the time taken for 50% of the active ingredient to be released into water), the release rate of imidacloprid is controlled by changing the thickness of the coating film and modifying its surface properties by adding a plasticizer. T 50 values, ranging from 3.02 to 168.6 h, allow supplying the appropriate amount of imidacloprid in each specific agronomic practice to increase the efficiency of this bioactive material and minimize the risk of environmental pollution.