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Determination of rifaximin in rat serum by ionic liquid based dispersive liquid–liquid microextraction combined with RP ‐ HPLC
Author(s) -
Nageswara Rao Ramisetti,
Mastan Vali Rajavarapu,
Vara Prasada Rao Alamanda
Publication year - 2012
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201200202
Subject(s) - chromatography , liquid liquid , ionic liquid , chemistry , high performance liquid chromatography , rifaximin , antibiotics , biochemistry , catalysis
An efficient and environmental friendly ionic liquid based dispersive liquid–liquid microextraction procedure was optimized for determination of rifaximin in rat serum by reverse phase high‐performance liquid chromatography. The effect of ionic liquids, dispersive solvents, extractant/disperser ratio, and salt concentrations on sample recovery and enrichment factors were studied. Among the five ionic liquids studied in the present investigation, 1‐butyl‐3‐methylimidazolium hexafluorophosphate was found to be most effective for extraction of rifaximin. The recovery was found to be more than 98% using 1‐butyl‐3‐methylimidazolium hexafluorophosphate and methanol as extraction and dispersive solvents, at an extractant/disperser ratio of 0.43. The recovery was further enhanced to 99.5% by the addition of 5.0% NaCl solution. A threefold enhancement in detection limit was achieved when compared to protein precipitation. The ionic liquid containing the extracted rifaximin was directly injected into HPLC system. The linear relationship was observed in the range of 0.03–10.0 μg/mL with the correlation coefficient ( r 2 ) 0.9998. Limits of detection and quantification were found to be 0.01 and 0.03 μg/mL, respectively. The relative standard deviation was 2.5%. The method was validated and applied to study pharmacokinetics of rifaxmin in rat serum.