Zero-Order Kinetic Release From Capsule Reservoirs through Semi-Permeable Polymer Membranes
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Transcript of Zero-Order Kinetic Release From Capsule Reservoirs through Semi-Permeable Polymer Membranes
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
http://apollo.lsc.vsc.edu/classes/met130/notes/chapter7/cond_pure_sat.html
Hansen Solubility Parameters
Ra2 = 4(δ D1 - δ D2) 2 + (δ P1 - δ P2) 2 + (δ H1 - δ H2) 2
RED > 1 : InsolubleRED < 1 : Soluble
Methods and Material
VEGETABLE CAPSULES
GEL CAPSULES
Petri Dish
Membrane
LiquidLiquid
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
0 2 4 6 8 10 121.48
1.5
1.52
1.54
1.56
1.58
R² = 0.925985951345299
R² = 0.808331055956662R² = 0.681997552522909
Diffusion of Acetone across Gelatin Capsules and Various Polymer Membranes (Trial A)
12% EVA
Linear (12% EVA)
10% EVA
Linear (10% EVA)
PE
Linear (PE)
Time Elapsed (Hours)
Gra
ms
Solv
ent
Rem
ain
ing
0 2 4 6 8 10 120.9
0.95
1
1.05
1.1
1.15
1.2
1.25
1.3
R² = 0.974217178153149
R² = 0.877973152484053
R² = 0.976239449903202
Diffusion of Pentane across Gelatin Capsules and Various Polymer Membranes (Trial B)
12% EVA
Linear (12% EVA)
10% EVA
Linear (10% EVA)
PE
Linear (PE)
Time Elapsed (Hours)
Gra
ms
Solv
ent
Rem
ain
ing
0 2 4 6 8 10 120.8
0.85
0.9
0.95
1
1.05
1.1
1.15
1.2
1.25
1.3
R² = 0.939515159909512
R² = 0.735221868707948
R² = 0.982246326271117
Diffusion of Pentane across Pullulan Capsules and Various Polymer Membranes (Trial B)
12% EVA
Linear (12% EVA)
10% EVA
Linear (10% EVA)
PE
Linear (PE)
Time Elapsed (Hours)
Gra
ms
Solv
ent
Rem
ain
ing
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