Comparison of Different CSAs

The resolution and splitting of the P NMR signals show an optimum at pH values between 9 and 11. The distance A between the signals of the two enantiomeric molecules strongly depends on the concentration of CD and more less on that of the cyclic phosphamide. Concentrated solutions of 100 mg/ml CD give baseline-separated signals. 

H-1 antihistamines [26], gliclazide [27], or thromboxane antagonists [28] could be well resolved. Derivatized CDs often exhibit improved chiral recognition properties [29]. //eptaA K(2,3-di-0-acetyl)-p-CD is able to resolve a series of pharmacologically active phenethylamines with their structures systematically varied [30],[31],[32]. Similar results have been reported for hydroxypropyl- as well as for permethylated P-CD [33] and perphenylearbamated P-CD to resolve atenolol [34], 

Taken together with regard to the determination of the isomeric composition of drugs, NMR has several advantages over HPLC  

The development and validation of an NMR method usually lakes a few weeks, while an HPLC methodology may take several months. 

NMR methods were found to be more robust than HPLC methods, which are subject to incalculabilities of column reproducibility and mobile phase composition a suitability test has to be performed to eliminate the vagaries of HPLC. 

---