Determination of the optical purity of (R)-terbutaline by 1H-NMR and RP-LC using chiral derivatizing agent, (S)-(-)-α-methylbenzyl isocyanate

A simple, convenient and precise H-1-NMR and indirect HPLC methods were used For the determination of (S)-terbutaline in (R)-terbutaline, The enantiomers were converted to diastereomeric derivatives using (S)-(-)-alpha -methylbenzyl isocyanate and were successfully separated on an ODS column within 40 min with R-S = 1.41 and alpha = 1.09. interaction between chiral solutes by the formation of the diastereomeric complexes also led to differentiations of the 1H-NMR spectra of enantiomers and optical purities were determined on the basis of the peak area of the enantiomeric amine proton resonance. The effect of various experimental parameter, such as reaction time. reaction temperature and concentration of chiral derivatizing agent on the derivatization reaction and composition of mobile phase on the ODS column is discussed. Validation data such as recovery, linearity and detection limit are also presented. The results from H-1-NMR and RP-HPLC methods M;ere compared with those from chiral HPLC method and no racemization was Found during the experiments. NMR results had agreed with those obtained by indirect HPLC method and two methods could be used as a quality control method for the enantiomeric purity determination of (R)-terbutaline. (C) 2001 Elsevier Science B.V. Ail rights reserved.