42 and the first few milliliters of the filtrate were discarded. Then 0.3 mL enough of filtered tablet sample solutions were transferred into five different 10 mL volumetric flasks, and the volume was made up to the mark with the buffer. The contents of the volumetric flasks were transferred into five different 125 mL separating funnels and 4 mL of methyl orange solution was added into each funnel. A 15 mL of chloroform was added into each separating funnel and shaken for 15 min and kept aside for 5 min. The chloroform layers were collected in the volumetric flasks and measured the absorbance at 427 nm. The concentration of the drug was calculated by employing the linear regression equation. The results of tablet analysis are shown in the Table 2.

Table 2 Analysis of commercial tablet (Gemez?) (*n=5) Procedure for assay in spiked urine (pure drug) In a 25 mL volumetric flask, 10 mL of urine, 5 mL of acetonitrile, and 10 mL of 30 ��g mL�C1 gemifloxacin solutions [in acetate buffer (pH 4)] were added. The resulting solution was filtered through a Whatman No. 42 filter paper and then transferred into a 125 mL separating funnel. Then, 4 mL of methyl orange solution (0.25%) was transferred into a separating funnel and 15 mL of chloroform were added into the separating funnel and shaken well for 5 min and kept aside for 5 min. The drug was extracted into the chloroform layer, and it was separated into 25 mL volumetric flasks. The organic layer was then passed over anhydrous sodium sulfate, and the maximum absorbance was measured at 427 nm against the reagent blank.

The blank solution was prepared by utilizing all the above reagents excluding the drug solution. The concentration of GEM in urine was found by using the linear regression equation. The results are given in the Table 3. Table 3 The results of pure drug in spiked urine Procedure for assay in spiked urine (formulation, i.e. tablet) In a 25 mL volumetric flask, 10 mL of urine, 5 mL of acetonitrile, and 10 mL of 30 ��g mL�C1 tablet sample solution [in acetate buffer (pH 4)] were added. The resulting solution was filtered through a Whatman No. 42 filter paper, and then transferred into a 125 mL separating funnel. Then, 4 mL of methyl orange solution (0.25%) was transferred into a separating funnel and 15 mL of chloroform were added into the separating funnel and shaken well for 5 min and kept aside for 5 min.

The drug was extracted into the chloroform layer, and it was separated into 25 mL volumetric flasks. The organic layer was then passed over anhydrous sodium sulfate, and the maximum absorbance was measured at 427 nm against Anacetrapib the reagent blank. The blank solution was prepared by utilizing all the above reagents excluding the drug solution. The concentration of GEM in urine was found by using the linear regression equation. The results are given in the Table 4.