title: Development and validation of chiral high-performance liquid chromatographic methods for the quantitation of valsartan and of the tosylate of valinebenzyl ester.
abstract: A stereospecific HPLC method for the quantitation of CGP 49309 in samples of its corresponding enantiomer valsartan has been developed and validated. The enantiomeric separation was achieved on a 5 micron silica-bonded, alpha 1-acid glycoprotein column (Chiral AGP) with a phosphate buffer, pH 7, containing 2% (v/v) 2-propanol as a mobile phase. The linearity was established in the range 0.1-4% (r > 0.999). The limit of quantitation was 0.1% and the limit of detection was 0.04%. The accuracy of the method was found to be 96.7% (average). For the precision (repeatability), a relative standard deviation value of 2.4% was found. Similarly, a stereoselective HPLC method was also developed and validated for the quantitation of the enantiomer of the starting material used for the synthesis of valsartan, namely (R)-valinebenzyl ester tosylate. Baseline resolution of the enantiomers of valinebenzyl ester tosylate could be achieved on the chiral crown ether column Crownpak CR (Daicel) at 50 degrees C using water-methanol-trifluoroacetic acid (850:150:1, v/v) as a mobile phase. The linearity was established in the range 0.5-5% (r > 0.999). The accuracy of the method was found to be 100.5% (average). For the precision (repeatability), a relative standard deviation value of 3.4% was found. Both methods were found to be suitable for the analysis of the respective analytes.
authors.affiliation: Ciba-Geigy Limited, Pharmaceuticals Division, Basel, Switzerland.
authors.forename: E
authors.initials: E
authors.lastname: Francotte
authors.forename: A
authors.initials: A
authors.lastname: Davatz
authors.forename: P
authors.initials: P
authors.lastname: Richert
mesh_terms: D000959:Antihypertensive Agents / Q000032:analysis* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004952:Esters / Q000737:chemistry; D016014:Linear Models; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013237:Stereoisomerism; D013777:Tetrazoles / Q000032:analysis* / Q000737:chemistry; D014105:Tosyl Compounds / Q000032:analysis* / Q000737:chemistry; D014633:Valine / Q000031:analogs & derivatives* / Q000032:analysis* / Q000737:chemistry; D000068756:Valsartan
chemical_list: D000959:Antihypertensive Agents; D004952:Esters; D013777:Tetrazoles; D014105:Tosyl Compounds; D000068756:Valsartan; D014633:Valine