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Determination of plasma phenobarbital concentration by high-performance liquid chromatography in rat offspring
M Moriyama1, S Yamashita, H Domoto
1Department of Hospital Pharmacy, Okayama University Medical School, Japan.
Insights
This study presents a new HPLC method for measuring plasma phenobarbital in rat offspring. The technique allows for accurate quantification without harming the animals, crucial for studying drug transfer via mother's milk.
Area of Science:
- Pharmacology
- Analytical Chemistry
- Toxicology
Background:
- Accurate measurement of plasma phenobarbital (PB) is essential for understanding its pharmacokinetics and potential teratogenicity in developing organisms.
- Existing methods for plasma PB analysis often require larger sample volumes, posing challenges for neonatal studies.
- Investigating drug transfer from mother to offspring, particularly via lactation, necessitates sensitive and minimally invasive analytical techniques.
Purpose of the Study:
- To develop and validate a novel high-performance liquid chromatography (HPLC) method for quantifying plasma phenobarbital (PB) concentrations in rat offspring.
- To establish a minimally invasive technique for serial blood sampling and analysis in neonatal rats.
- To assess the feasibility of using this method to determine PB levels transferred from maternal milk.
Main Methods:
- Utilized a 9 microl capillary for plasma collection from rat offspring.
- Employed a Bond Elut cartridge for sample extraction, with acetanilide as the internal standard (I.S.).
- Analyzed samples using high-performance liquid chromatography (HPLC) with methanol elution.
Main Results:
- Demonstrated excellent linear correlation between PB concentration and capillary length.
- Achieved linear calibration for PB in the range of 0-50 microg/ml.
- Reported high extraction recovery rates (87.5-105.4%) and acceptable coefficients of variation (3.4-7.5%) for within-day and between-day assays.
Conclusions:
- The developed HPLC method enables precise and accurate determination of plasma PB concentrations in rat offspring using minimal sample volumes.
- This technique allows for serial measurements without the need to sacrifice the animals, facilitating longitudinal studies.
- The method is highly suitable for investigating phenobarbital transfer and its pharmacokinetics in neonates via maternal milk.
Abstract:
Plasma phenobarbital (PB) concentrations in rat offspring were determined using a 9 microl capillary by high-performance liquid chromatography (HPLC). Capillary plasma which was put into a Bond Elut cartridge column by using 1 ml of 0.01 M KH2PO4 was applied to the column with 50 microl of 2 microg/ml of acetanilide (internal standard, I.S.). After washing the column, PB and I.S. were eluted with methanol and injected into the HPLC system. There were excellent linear correlation between the amount of PB and length of the capillary at three different concentrations. Calibration for PB was linear in the range of 0-50 microg/ml. The coefficients of variation were 3.4-5.0% and 5.9-7.5% in the within-day and between-day assays, respectively. The extraction recovery rates were 87.5-105.4%. By this method, it was possible to measure plasma PB concentrations in rat offspring without killing. These results suggested that this method is very useful to determine the plasma PB concentration derived from mother's milk in newborn rats.