Engineering HDR Seminar Series 4, 2013: Coating of Oil-loaded Gel Core by Inverse-gelation Method

Ms Ong Wan Ding, postgraduate student from Chem Eng

Date: 2013-02-04
Time: 11:00 to 12:00
Venue: Engineering Meeting Room 1, 5-4-22


Many pharmaceutical and food active compounds exist in oil form and they are often encapsulated in polymer matrix and spray-dried into powder form to facilitate handling, reconstitution and storage. The oil loaded powders usually have poor flowability, handling and reconstitution properties due to the presence of surface oil especially at high oil content (i.e. > 50% of oil on dry basis). A coating process can be applied to improve the surface properties of particles using fluidised bed agglomeration, film coating or electrostatic spray powder coating. However, these methods require specialized equipment, and the use of high temperature and air which may cause thermal or oxidation degradation of active compounds. This study aims to establish a novel coating method to form a hydrogel membrane encasing oil-loaded gel-core by inverse gelation technique. The coating is performed prior to the spray-drying process to avoid the post-drying coating problems. This method involves incorporation of an insoluble coating precursor into an oil-loaded gel-core, followed by pH reduction which triggers the dissolution of the precursor. The solubilized precursor then diffuses outward to the interface of gel particle and crosslinks with a coating polymer to form a continuous hydrogel layer around the gel-core. This coating process can be performed using simple equipment and it operates at ambient temperature and pressure without the use of air. Since the coating mechanism is diffusion-controlled, the permeability of hydrogel and thickness of the hydrogel membrane can easily be tuned. The coating process will be modeled using Fick’s law of diffusion.

About the Speaker

Ms Ong Wan Ding graduated from University Malaysia Sabah (UMS) with Bachelor of Chemical Engineering (Honours) in year 2011. She joined Monash University for postgraduate studies in year 2012 under the supervision of Assoc. Prof. Chan Eng Seng and  Prof. Tey Beng Ti.  Her research in Monash University is focused on the development of a novel coating method to coat oil-loaded gel-core by inverse gelation technique.