Enantiomeric HPLC Separations of Chiral Local Anesthetics Using Cellulose Based Chiral Stationary Phases

Abstract

Enantiomeric resolution of four racemic local anesthetics bupivacaine, mepivacaine, prilocaine and etidocaine were investigated on cellulose based chiral stationary phases. The phases studied were cellulose tris-3,5-dimethyl phenylcarbamate (Chiralcel OD) and cellulose trisbenzoate (Chiralcel OJ). Baseline separation (Rs>1.5) were achieved for bupivacaine and prilocaine enantiomers on Chiralcel OD using hexane-ethyl alcohol (99:1, v/v) and for etidocaine enantiomers on Chiralcel OJ using hexane-methanol (98:2, v/v). Etidocaine and mepivacaine enantiomers only gave partial separations (Rs≤0.81) on Chiralcel OD. The effects of various protic and aprotic organic modifiers were investigated on resolution and retention of the enantiomers.

Key Words:

• Chiral local anesthetics
• cellulose tris-3,5-dimethyl phenylcarbamate
• cellulose trisbenzoate
• protic modifiers
• aprotic modifiers