Materials World Modules

An Inquiry & Design-Based Science, Technology, Engineering, and Mathematics (STEM) Education Program

Modeling Controlled Drug Delivery: Release from Alginate Bead

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This interactive applet illustrates the mechanisms of dissolution rate and chemical release from alginate beads in water, which can be used to design time-release of drugs for therapeutic applications. A certain concentration of a dye is assigned to the alginate beads, to represent the presence of the drug to be released. The mathematical model assumes that water absorbs into the alginate beads very quickly relative to the dissolution and release of dye from the beads, and that the diffusion of the dye through the alginate is much slower than the bead dissolution rate. The dissolution rate of the beads is assumed to be constant in time, which should be approximately true for an experiment where the slurry is mixed at a constant rate over time. Up to five different alginate bead sizes can be specified by the user in any desired relative proportion for a given initial total mass of the beads. In this way, a variety of practical experimental conditions can be simulated. The bead dissolution rate is also an input parameter which can be adjusted, using data from actual experimental observations.

Applet Design:

Prof. Umberto Ravaioli, University of Illinois at Urbana-Champaign, Urbana, IL, USA 


Prof. Richard Braatz, Massachusetts Institute of Technology, Cambridge, MA, USA

Prof. Umberto Ravaioli1,

Prof. Richard Braatz2.

1University of Illinois at Urbana-Champaign, USA; 2Massachusetts Institute of Technology, USA.

High School

Approximate Time:
10-15 minutes

For Classroom:
This simulator was developed to be used with MWM Nanoscale Drug Delivery module. 

This interactive mathematical model has been developed to enable students to make predictions of the drug release rate of different sized beads. It also allows students to enter combinations of bead sizes and obtain an overall release rate as a function of time. This tool can be introduced to students prior to the design project or made available to students on the first day during the brainstorming stage.




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