[Formulation of immediate release lamotrigine tablets and bioequivalence study]

ABSTRACT

Lamotrigine tablets were compressed directly by means of Avicel PH102, sodium starch glycolate, magnesium stearate, Aerosil 200 and PVPK25. A rapid, sensitive and simple high-performance liquid chromatographic [HPLC] method for the determination of lamotrigine in plasma is described. The drug was extracted from one mL of each rabbits plasma sample, then it was transferred into a 15 mL tube fitted with a polyethylene cap, 1 mL acetonitrile were added to the sample, and the supernatant was injected into the HPLC system. The drug and the internal control [carbamazepine] were eluted from C18 Zorbax ODS [4.6x250mm, USA] column at ambient temperature with a mobile phase consisting of acetonitrile and 20mM potassium dihydrogen phosphate buffer [3565, v/v] and adjusted to [pH 7] using 1N NaOH, at a flow rate of 1.5 ml min[-1] and the detector was monitored at 210 nm. Quantitation was achieved by measurement of the peak-area ratio of the drug to the internal standard and the lower limit of detection for malotrigine in plasma was 0.491 micro g ml[-1]. The intraday precision ranged from 0.801-7.692% [coefficient of variation] [CV] and accuracy [relative error%] ranged from 0.048-4.9 for all samples. The relative recoveries of lamotrigine ranged from 95.10 to 101.89%. The method was applied in studying the pharmacokinetics of lamotrigine administered orally to rabbits. This reliable micro-method would have application in pharmacokinetic studies of lamotrigine. The relative percentage bioavailability of prepared lamotrigine tablets with respect to the commercially available Lamictal [registered sign] tablets was 134.68%