Asian Journal of Biomedical and Pharmaceutical Sciences

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Application of validated RP ? HPLC method for estimation of pharmacokinetic parameters of novel satranidazole formulation

Satranidazole, a BCS class II antiprotozoal drug has poor solubility. In vitro dissolution studies have demonstrated enhanced solubility and improved dissolution rate of satranidazole solid dispersion. However in vivo studies are necessary to provide a proof of enhanced bioavailability and therapeutic efficacy of the formulated solid dispersion. Though bioanalytical methods for estimation of satranidazole have been reported, its application for bioequivalence studies of satranidazole solid dispersion is yet to be explored. The objective of the present study was to apply validated reversed phase high-performance liquid chromatography (RP-HPLC) method for in vivo estimation of satranidazole and compare various pharmacokinetic parameters of pure satranidazole and its solid dispersion. Satranidazole solid dispersion was formulated by solvent evaporation technique using Plasdone® S 630 as hydrophilic carrier. The validated assay procedure involved extraction of satranidazole and internal standard (IS) Tinidazole, from plasma by protein precipitation. The chromatographic method used Kromasil C18 (4.6 mm × 250 mm, 5μ) column. Mobile phase of phosphate buffer (0.01M, pH3.5): acetonitrile (65:35, v/v), was used at a flow rate of 1.0 mL/min. The eluate was monitored using a diode array detector set at 320 nm. Pure satranidazole and the formulated solid dispersion were administered orally (50 mg/kg) to male Wistar rats. Nominal retention times of IS and satranidazole were 5.5 and 7.7 min respectively. The method was found to be linear (R2 > 0.999) in the concentration range 0.5 – 70 μg/mL. Absolute recovery was > 90% for both analyte and IS. The lower limit of quantification was 0.5 μg/mL. Analyte and IS were found to be stable during the freeze/thaw cycles, benchtop stability and long term stability. Satranidazole solid dispersion on oral administration to male Wistar rats demonstrated 1.85 folds increase in Cmax and 164% increase in bioavailability as compared to pure satranidazole. However tmax values when compared using Wilcoxon rank sum test were found to be similar (p> 0.05). A specific, accurate, precise and reproducible RP-HPLC method was applied successfully for estimating the enhanced bioavailability and increase in Cmax of satranidazole solid dispersion.

Author(s): Dhat S, Dumbre S, Kokare C, Sharma P, Shrivastava B