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Reverse Iontophoretic Extraction of Gabapentin: A Mechanistic Study
Subhasis Chakrabarty1, Bijaya Ghosh1,2, Tapan K Giri1
1NSHM College of Pharmaceutical Technology, NSHM Knowledge Campus, Kolkata Group of Institutions, 124 BL Saha Road, Kolkata-700053, West Bengal, India.
Current Drug Delivery
|May 8, 2018
Summary
Transdermal reverse iontophoresis can extract gabapentin for noninvasive therapeutic drug monitoring. Cathodal extraction showed higher rates, influenced by time and pH, suggesting orientation-mediated electromigration.
Area of Science:
- Analytical Chemistry
- Pharmaceutical Science
- Biomedical Engineering
Background:
- Narrow therapeutic index anti-epileptic drugs require plasma concentration monitoring to prevent complications from fluctuating levels.
- Noninvasive therapeutic drug monitoring is desirable for patient convenience and adherence.
Purpose of the Study:
- To investigate the feasibility of transdermal reverse iontophoresis for extracting gabapentin.
- To explore gabapentin's potential for noninvasive therapeutic drug monitoring.
Main Methods:
- Gabapentin extraction using transdermal reverse iontophoresis from phosphate buffer (pH 7.4) at therapeutic concentrations (2-10 µg/ml).
- Extractions performed under an electric field (5 V, 0.3-0.5 mA/cm²) for 4 hours, with samples analyzed hourly by HPLC.
- Investigated effects of time, pH, and current intensity on extraction efficiency.
Main Results:
- Gabapentin was extracted at both anode and cathode, with higher rates observed at the cathode.
- Extraction efficiency was influenced by time, with the highest rates in the first hour.
- Optimal extraction occurred at pH 5, and anodal extraction showed a stronger positive correlation with current intensity.
Conclusions:
- Orientation-mediated electromigration is proposed as the mechanism for gabapentin extraction at pH 7.4, where it carries no net charge.
- Transdermal reverse iontophoresis demonstrates potential for noninvasive gabapentin monitoring.
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