Direct injection assay of drug enantiomers in serum on ovomucoid-bonded silica materials by liquid chromatography.

A high-performance liquid chromatographic (HPLC) method for the determination of drug enantiomers in serum was developed. The method involves direct injection of serum samples on to an ovomucoid-bonded column, which is prepared by bonding of ovomucoid proteins to an aminopropyl-silica gel by the N,N'-disuccinimidyl carbonate activation method and separation of drug enantiomers on the column using a mixture of phosphate buffer and an organic solvent. High recoveries of serum proteins were obtained using eluent pH values of 3, 4, 6 and 7 at phosphate buffer concentrations above 50 mM, whereas the recovery was ca. 70% at an eluent pH of 5. The recovery of each enantiomer of basic and acidic drugs from serum was almost 100%.