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Mexiletine-sensitive membrane electrode for medical application.
1Faculty of Pharmaceutical Sciences, Okayama University, Tsushima-naka, Japan. katsu@pheasant.pharm.okayama-u.ac.jp
Journal of Pharmaceutical and Biomedical Analysis
|March 7, 2000
Summary
An ion-exchange electrode offers a sensitive and selective method for measuring mexiletine drug concentrations in saliva. This noninvasive approach aids in effective drug dosage control.
Area of Science:
- Analytical Chemistry
- Electrochemistry
- Pharmaceutical Analysis
Background:
- Accurate determination of drug concentrations is crucial for therapeutic efficacy and patient safety.
- Noninvasive methods for monitoring drug levels, such as saliva analysis, are highly desirable for patient convenience and dose adjustment.
Purpose of the Study:
- To develop and evaluate a mexiletine-sensitive electrode for determining drug concentrations under physiological conditions.
- To compare the performance of crown ether-based and ion-exchanger-based electrodes for mexiletine detection.
- To assess the feasibility of using the developed electrode for noninvasive monitoring of mexiletine in saliva.
Main Methods:
- Screening of various crown ethers and ion-exchangers for mexiletine sensitivity in physiological saline.
- Characterization of electrode response, including sensitivity and detection limits.
- Evaluation of electrode selectivity against common inorganic cations (Na+, K+).
- Determination of mexiletine concentrations in saliva samples using the optimized ion-exchanger electrode.
- Comparison of results with high-performance liquid chromatography (HPLC).
Main Results:
- The 4',4"(5")-di-tert-butyldicyclohexano-18-crown6 crown ether exhibited high sensitivity but a higher detection limit (30 microM).
- The ion-exchanger electrode, utilizing sodium tetrakis[3,5-bis(2-methoxyhexafluoro-2-propyl)phenyl]borate, demonstrated a significantly lower detection limit (3 microM).
- The ion-exchanger electrode showed high selectivity against Na+ and K+ ions.
- Mexiletine concentrations determined in saliva using the ion-exchanger electrode correlated well with HPLC measurements.
Conclusions:
- The ion-exchanger based electrode is a suitable tool for determining mexiletine concentrations in physiological samples like saliva.
- This electrode offers a selective and sensitive method for noninvasive monitoring, facilitating effective drug dose control.
- The developed electrochemical method provides a viable alternative to traditional analytical techniques requiring complex sample preparation.