Suppressive effect of chronic peroral topiramate on potassium-induced cortical spreading depression in rats

OBJECTIVE

To evaluate the chronic effect of topiramate (TPM) on cortical spreading depression (CSD), which is thought to be related to migraine aura.

METHODS

Male rats (n = 30) were randomized to once-daily peroral treatment with TPM (50, 100, 200 or 600 mg/kg) or vehicle for 6 weeks. We evaluated the characteristics of CSD induced by topical application of KCl under isoflurane anesthesia and the changes in plasma level of TPM in each group. The effect of single administration of TPM on CSD was also evaluated.

RESULTS

After the final administration of TPM, when the plasma level of TPM was high, KCl-induced CSD frequency and CSD propagation velocity were dose-dependently reduced and the interval between CSD episodes was elongated, compared with the vehicle control. However, before the final administration of TPM, when the plasma level was very low, the KCl-induced CSD profile was the same as that in the vehicle control. Single administration of TPM did not alter the CSD profile. Local cerebral blood flow was not significantly altered by chronic administration of TPM.

CONCLUSION

TPM suppressed the frequency and propagation of CSD along the cerebral cortex, and might be a candidate for relief of migraine.

A simple, rapid and specific method for measurement of topiramate in human plasma by LC-MS/MS employing automated solid-phase extraction techniques: Application for bioequivalence study

A rapid liquid chromatography coupled with ESI tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of topiramate in heparinized human plasma. The plasma samples were prepared by solid-phase extraction (SPE) method without drying and then reconstitution. Topiramate and the topiramate d-12 internal standard (IS) were chromatographed on a Betasil C18 column at a flow rate of 0.5 mL/min. The total run time was 1.80 min. An ESI interface with negative ion mode was selected for ionization of analyte and IS. The mass transition [M-H] ions used for detection were m/z 338.10→78.20 for topiramate, m/z 350.40→90.10 for IS. The method was linear in the concentration range of 10-4200 ng/mL with r≥0.9992. Recovery of topiramate and IS ranged from 78.20 to 87.74%. The validated method has been successfully used to analyze human plasma samples for application in 100 mg fasted and fed pharmacokinetic studies.