Thin Layer Chromatography Identification Test for Etodolac following European Pharmacopeia Monograph on Silica Gel G F 254 Plates

Introduction

Etodolac is a nonsteroidal anti-inflammatory drug (NSAID).
Etodolac is a white crystalline compound, a racemic mixture of [+]S and [-]R-enantiomers insoluble in water but soluble in alcohols, chloroform, dimethyl sulfoxide, and aqueous polyethylene glycol.

This application note uses TLC Silica gel 60G plates for Etodolac identification following the current European pharmacopoeia monograph (version 9.1).

Etodolac

Etodolac

 

Experimental Conditions
TLC Plate Silica Gel 60G F254 20 x 20 cm preheated at 105° C for one hour
Application Volume 10 µl
Detection UV @ 254 nm
Mobile Phase Mix glacial acetic acid ,anhydrous ethanol, toluene 0.5:30:70 (v/v/v)
Plate development Place the plate in an unsaturated tank containing a mixture of 20 volumes of a 25 g/L solution of ascorbic acid and 80 volumes of Methanol. Allow the solution to ascend 1 cm above the line of application on the plate ,remove the plate and allow it to dry for 30 minutes. Spot the plate with standard and sample solution and place the plate in a tank containing mobile phase.
Development Over 2/3rd of the plate
Diluent Acetone
Drying In air
Standard Dissolve 10 mg of standard etodolac in acetone and dilute to 10 ml with the same solvent
Sample Dissolve 10 mg substance to be examined in acetone and dilute to 10 ml with the same solvent .

 

plate development


chromatogram

Chromatogram

 

Absorbance spectrum of standard and sample

Absorbance spectrum of standard and sample

 

Chromatographic Data (Standard Solution)

Chromatographic Data (Standard Solution)

  Compound Rf Area
1 Etodolac 0.57 14451

 

Chromatographic Data (Sample)

Chromatographic Data (Sample)

  Compound Rf Area
1 Etodolac 0.56 14711

 

Standard Repeatability
STD 1 13929.3
STD 2 14383.7
STD 3 14386.6
STD 4 14204.9
STD 5 14041.2
Mean 14189.1
Standard Deviation 204.01
RSD (%) 1.4

Summary

  1. The principal spot in the chromatogram obtained with the test solution is similar in position and size to the principal spot in the chromatogram obtained with the reference solution.
  2. Plate repeatability is better than 2 % relative standard deviation (RSD) for reference solution (n=5).
  3. Silica gel G plates, coated with the fluorescent indicator F254, are appropriate tools to comply with European Pharmacopoeia requirements for identification tests, as illustrated here for Etodolac.

Materials

     
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