A simple, rapid and precise thin-layer chromatographic (TLC) method for analysis of escitalopram oxalate (ESC-OX) (S-enantiomer) in presence of “in-process impurities” using β-cyclodextrin (β-CD) and urea as two different selectors was developed and validated as per ICH guidelines. Chromatography was performed on silica gel 60 F254 plates with acetonitrile-0.1% acetic acid-methanol-water (5:0.5:3:1 ν/ν) as a mobile phase containing 3 mg β-CD per 100 cm2 of silica-coated plates as a chiral additive. Using urea 3 mg per 100 cm2 of silica-coated plates as a chiral additive also achieves a good enantiomeric separation with acetonitrile-1% acetic acid-ethyl acetate-methanol-water (5:0.5:1:2:1.5 ν/ν) as a mobile phase. Successful resolution was observed for the (S-enantiomer) ESC-OX, escitalopram cyanodiol, the R-enantiomer and escitalopram N-oxide impurities with significant RF values of 0.75 ± 0.02; 0.40 ± 0.02; 0.31 ± 0.02 and 0.23 ± 0.02, respectively. Densitometric measurement of (S-enantiomer) ESC-OX was carried out at 240 nm. The linear regression analysis data for the calibration plots showed a good correlation coefficient(r = 0.9991) at concentration range of 0.25–10 mg per 10 mL with percentage accuracy 99.74 ± 0.42 for ESC-OX. The limits of detection and quantitation were 0.133 and 0.44 mg per 10 mL, respectively. The proposed TLC method was applied to investigate the enantiomeric purity of (S-enantiomer) ESC-OX in drug substance and drug product. Uniformity of dosage units was demonstrated according to USP guidelines.
S.C. Martindale, The Complete Drug Reference, 36th edn., Pharmaceutical Press, London, 2009, pp. 385–391.
Martindale S.C., '', in The Complete Drug Reference, (2009) -.
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C. Sánchez, K.P. Bøgesø, B. Ebert, E. Heldbo, R. C. Braestrup, Psychopharmacology 174 (2004) 163–176.
Braestrup R. C., '' (2004) 174Psychopharmacology: 163-176.
Braestrup R. C.Psychopharmacology2004174163176)| false