Preparation and characterization of a controlled-release formulation based on carbofuran loaded in ionically cross-linke
- PDF / 2,865,828 Bytes
- 12 Pages / 595.276 x 790.866 pts Page_size
- 108 Downloads / 193 Views
ORIGINAL PAPER
Preparation and characterization of a controlled‑release formulation based on carbofuran loaded in ionically cross‑linked chitosan microparticles Rubén Albeiro Sánchez‑Andica1 · Martha Isabel Páez‑Melo1 · Margarita Sánchez‑Domínguez2 Received: 28 January 2020 / Accepted: 1 September 2020 © The Polymer Society, Taipei 2020
Abstract A controlled-release formulation (CRF) of the nematicide carbofuran (CAB) was prepared using ionically cross-linked chitosan (CHS). Four cross-linker agents were assessed, among which sulfate (SUL) obtained the highest encapsulation efficiency. Several parameters for the encapsulation of the pesticide were optimized, including pH, SUL/CHS molar ratio, stirring time, and stirring speed. The EE and the pesticide loading (PL) were 67% and 24%, respectively, in the optimized process. Scanning electron microscopy (SEM) images for empty microparticles (EMP) showed a rough and porous surface, with particle size of 1023 nm, whereas the CRF surface was found to be smoother, with a particle size of 1127 nm. The release kinetics of CAB from CRF and commercial carbofuran (CC) were evaluated in water under laboratory conditions, and the release data were fitted to the generalized Korsmeyer-Peppas model. The results indicated that the release of CAB was accomplished by a diffusion-controlled process. The CAB release from CRF was slower than that from CC, and required 6 days for 70% release, whereas CC required 5 days for 100% delivery of the pesticide. A diffusion coefficient (n) of 0.603 was determined, meaning that delivery was not governed by Fick’s laws of diffusion, but by an anomalous transport mechanism. Keywords Carbofuran · Chitosan · Cross-linking · Encapsulation · Controlled-release
Introduction The disruption of the balance in ecosystems caused by agricultural industrialization has led to outbreaks of pests (insects, fungi, weed, nematodes, etc.) [1, 2], which have been effectively controlled with synthetic chemical compounds called pesticides [3]. Carbofuran (2,2-dimethyl-3H-benzofuran-7-yl) is a pesticide belonging to the carbamate family, very suitable for root-level nematode control [4, 5]. To achieve adequate control of this type of pest, it is necessary to maintain a constant * Rubén Albeiro Sánchez‑Andica [email protected] 1
Grupo de Investigación en Contaminación Ambiental Por Metales Pesados Y Plaguicidas, GICAMP, Departamento de Química, Universidad del Valle, Calle 13 No 100‑00, 760036 Cali, Colombia
Centro de Investigación en Materiales Avanzados, S.C. (CIMAV), Parque de Investigación e innovación Tecnológica, Unidad Monterrey Alianza norte 202, Nuevo León 66628 Apodaca, México
2
and regulated amount of the pesticide in the rhizome [6], However, CAB has been applied using unsuitable techniques and in large amounts, such that the excess (approximately 90% of the total used) is released into the environment, reaching non-target species, many times including humans [7]. Several papers regarding the harmful effects of this pesticide
Data Loading...
