Zero-Order Kinetic Release From Capsule Reservoirs through Semi-Permeable Polymer Membranes Denise Bion, Matthew Blank, Dylan Freas, Craig Gambogi, Demetris Rotsides, Sadik Shahidain, Daniel Ye, Barbara Zhan Dr. David Cincotta, Amanda Garfinkel

Controlled-Release Kinetics Study of the rates of chemical processes Most are naturally first or second- order Zero-order reactions usually do not occur spontaneously “Pseudo-zero-order reactions”

Applications of Controlled- Release Kinetics Very effective medical treatment Prevents drugs from reaching near-toxic levels (such as those in chemotherapeutic treatments) Helps maintain safe but effective concentrations

Polymers Series of repeated monomer units  long chains Many properties affect permeability: Chain length Chain branching Intermolecular forces Different properties result in different diffusion rates

Microspheres (Nanyang Experiment)  BSA loaded into microspheres  Drug Immobilized in PEG membrane  Microsphere acts as an unlimited reservoir  BSA diffuses over a long period of time

Fick’s Law Constant concentration  pseudo-zero-order release Fick’s Law goes against the concept of a zero-order release mechanism

Hypothesis Constant vapor pressure  zero-order release Goal: To create a zero-order release mechanism

Hansen Solubility Parameters R a 2 = 4(δ D1 - δ D2 ) 2 + (δ P1 - δ P2 ) 2 + (δ H1 - δ H2 ) 2 RED > 1 : Insoluble RED < 1 : Soluble

Methods and Material VEGETABLE CAPSULES GEL CAPSULES Petri Dish Membrane Liquid

Final Experiment Petri Dish Membrane Liquid 2 mL

Overview  3 polymer membranes, 2 organic solvents, 2 types of capsules  9 combinations of solvent, capsule, and membrane tested  12-hour experimental window  Systems were massed every two hours

Error Analysis  Rubber band flaw  Cool down every two hours for massing  Excess membrane  Few data points due to long duration of diffusion

Conclusion  Pseudo-zero-order release w/ capsules and membrane is possible  Many combinations exhibited strong, linear releases  Our model justifies microsphere experiment

Future Studies  Capsules relevant to biological systems  Further experiments on controlling rate of release

 Dr. David Cincotta, advisor  Amanda Garfinkel, assistant  Dr. David Miyamoto, director  NJGSS and sponsors, providing the opportunity for this experience Acknowledgements