Rapid, sensitive, and validated HPLC method for analysis of metronidazole and tinidazole under identical chromatographic conditions with UV detection and liquid-liquid extraction: application in bioequivalence studies

Abstract

Summary.A simple, rapid, and sensitive reversed-phase HPLC method was developed and validated for determination of metronidazole and tinidazole in human plasma samples under identical chromatographic conditions. This method involves liquid-liquid extraction using chloroform: isopropylalcohol (95:5). Chromatographic separation was performed using a μ-bondapack C18 (250 mm × 4.6 mm) column. The mobile phase consisted of potassium dihydrogen phosphate solution (0.005 M)/acetonitrile (80/20 v/v). The final pH of the mobile phase was adjusted to 4 ± 0.1 with orthophosphoric acid. The calibration curves were linear over the concentration range 0.1-15 μg/mL for metronidazole and tinidazole with the detection limit of 30 ng/mL. Within-and between-day precision and accuracy did not exceed 9.83% and 10.48%, respectively. Metronidazole and tinidazole were found to be stable in plasma samples with no evidence of degradation during 3 freeze-thaw cycles and 3 months storage in −70 °C. The current validated bio-analytical method was finally applied in bioequivalence studies of two different metronidazole and tinidazole products according to a standard two-way cross-over design with a two-week washout period. No statistically significant difference was observed between the logarithmically transformed AUC 0-∞ and C max values. Therefore, generic products were considered bioequivalent with those of standards which could be used interchangeably.

A Rapid and Sensitive HPLC Method for Quantitation of Paclitaxel in Biological Samples using Liquid-Liquid Extraction and UV Detection: Application to Pharmacokinetics and Tissues Distribution Study of Paclitaxel Loaded Targeted Polymeric Micelles in.....

“…The analyte concentration that produced a signal-to-noise ratio of 3:1 was accepted as the LOD. The LOQ was identified as the lowest plasma and tissue concentrations of the standard curves that could be quantified with acceptable accuracy, precision and variability (33).…”

“…Stability of PTX in mouse plasma containing PTX/TS-CS-PEG-FA or Anzatax ® was examined by keeping replicates of plasma samples at room temperature for 12 h. Freeze-thaw stability of PTX in mouse plasma samples were studied over three freeze-thaw cycles, by thawing at room temperature for 2-3 h and refrozen for 12-24 h. Stability of the drug in plasma was also tested after storage at below −70 °C for 3 months (33). In all stability studies, plasma samples were spiked with PTX/TS-CS-PEG-FA or Anzatax ® at three concentrations of PTX, low (0.25 µg/ml), medium (5µg/ml), and high (10 µg/ml).…”

A simple and sensitive high-performance liquid chromatography method for determination of ciprofloxacin in bioavailability studies of conventional and gastroretentive prolonged-release formulations

“…The LOQ was identified as the lowest plasma concentration of the standard curves that could be quantified with acceptable accuracy, precision, and variability. [22]…”

“…Samples were considered stable if the assay values were within the acceptable limits of accuracy and precision. [22]…”

Direct nano-electrospray ionization tandem mass spectrometry for the quantification and identification of metronidazole in its dosage form and human urine

“…Several methods have been reported for the determination of MTZ from its individual or combined formulations with other active ingredients using spectrophotometry [4][5][6][7], electrochemistry [8][9][10][11], capillary electrophoresis [12][13][14], gas chromatography (GC) [15][16][17][18], high-performance liquid chromatography (HPLC) coupled with ultraviolet [19][20][21][22][23][24][25] and mass spectrometric detector methods [26][27][28][29][30][31][32][33][34].…”