Preparation and optimization of 2,4‐D loaded cellulose derivatives microspheres by solvent evaporation technique

Abstract

Controlled release herbicide formulations were prepared by microencapsulation using solvent evaporation technique. 2,4-D was chosen as core material, which was microencapsulated in two cellulose derivatives as matrices: cellulose acetate butyrate butyryl (CAB) and ethylcellulose (EC). The work is intended to produce systems containing the herbicide to reduce its risks by dermal contact, evaporation, or degradation and to control the release of the active agent. The microspheres loaded by 2,4-D were characterized by scanning electron microscopy and infrared spectroscopy. We have obtained microparticles in the range of D 32 of 42-277 mm with CAB and 88-744 mm with EC by varying the process parameters. The drug entrapment was improved by controlling certain factors such as polymer/solvent ratio, pH of continuous phase, and organic phase solvent. The drug release was established in deionized water at pH ¼ 5.5 and 258C and the 2,4-D concentrations were estimated by UV analysis. The release data were analyzed according to Fick's law and the results demonstrate that the release rate can be controlled by modifying the process parameters.

Preparation of aqueous dispersion of thermoplastic sizing agent for carbon fiber by emulsion/solvent evaporation

“…1): the emulsification of a polymer solution containing the encapsulated substance, followed by particle hardening through solvent evaporation and polymer precipitation. During the water emulsification, the polymer in solution in the volatile, waterimmiscible solvent is broken into microdroplets by the shear stress produced by either a homogenizer or a sonicator in the presence of a surface-active agent until the polymer precipitates [24][25][26][27].…”

In vitro release study of 2-aminobenzothiazole from microspheres as drug carriers

“…These systems provide a pH-dependent drug release mechanism. [20][21][22] In drug microencapsulation, [23][24][25] the most used class of hydrophobic polymers is cellulose derivatives including ethyl cellulose (EC) and cellulose acetate butyrate (CAB) for a prolonged release. 26 Jelvehgari et al have shown that CAB formulations exhibit enough buoyancy to reside in the stomach over a prolonged and slower drug release.…”

“…41 The same remark was reported for other drug/EC microspheres preparations. 23,41 Considering the nature of the polymer matrix under the same process conditions, The CAB microspheres were smaller than the EC microspheres. Based on the particle sizes values, microspheres with a mean Sauter diameter of 166 µm with EC and of 113 µm with CAB were obtained.…”

Elaboration of Microspheres’ Capsules Based on Ethylcellulose and Synthesized Poly (Butylsuccinate) as Biodegradable Matrices for Drug Delivery of an Antithyroidian Agent

“…[9][10][11] Aliphatic polyester polymers degrade in to non-toxic monomers by bulk hydrolysis of the ester bonds, then avoiding the need for surgical removal so the risk of long term toxicity or a probable immunological reaction when compared with non degradable systems is also minimized. 12 Micro-encapsulation is a method of fabricating materials with valuable new properties in the pharmaceutical industry 13,14 and other fields; [15][16][17] it is one of the quality preservation techniques of sensitive substances. In current pharmacology, micro-encapsulation is employed as a masking technique and, in particular, to control and modify drug release.…”