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Ion-pairs of ibuprofen: increased membrane diffusion
Vikram Sarveiya1, John F Templeton, Heather A E Benson
1Faculty of Pharmacy, University of Manitoba, Manitoba, Canada.
The Journal of Pharmacy and Pharmacology
|July 3, 2004
Summary
This study shows that increasing pH and forming ion-pairs significantly enhances ibuprofen permeation across membranes. Ibuprofen triethylamine showed the highest flux, demonstrating ion-pairing
Area of Science:
- Pharmaceutical Sciences
- Physical Chemistry
- Materials Science
Background:
- Understanding drug permeation across membranes is crucial for drug delivery.
- Polydimethylsiloxane (PDMS) is a common model for lipophilic biological membranes.
- Ibuprofen's physicochemical properties, like pH-dependent solubility, influence its transport.
Purpose of the Study:
- To investigate how pH and ion-pairing affect ibuprofen permeation through a PDMS membrane.
- To explore the synthesis and impact of ibuprofen's organic salts on membrane diffusion.
- To correlate physicochemical properties with ibuprofen flux.
Main Methods:
- Determined ibuprofen sodium solubility and apparent partition coefficients at various pH values.
- Synthesized ibuprofen organic salts with different counter-ions (ethylamine, diethylamine, triethylamine, ethylene diamine).
- Measured ibuprofen diffusion flux across PDMS membranes using techniques like NMR for ion-pairing confirmation.
Main Results:
- Ibuprofen sodium flux significantly increased with pH from 4.0 to 7.0, decreasing above pH 7.0.
- Permeability coefficient correlated positively with the unionized acid fraction.
- Ion-pairing with counter-ions increased ibuprofen flux up to 16-fold, with ibuprofen triethylamine showing the highest flux.
Conclusions:
- Ion-pair formation effectively enhances ibuprofen flux across lipophilic membranes.
- The degree of flux enhancement depends on lipophilicity, ion-pairing extent, and charge reduction.
- Optimizing pH and utilizing ion-pairing strategies can improve ibuprofen delivery.