Specific determination of unbound oxacillin in protein solution with cefoperazone by high‐performance frontal analysis with chemiluminescence detection

Abstract

Unbound oxacillin concentrations in human serum albumin (HSA) solutions in the presence or absence of cefoperazone were determined using high-performance frontal analysis coupled with chemiluminescence detection (HPFA-CL). The HPFA was performed on an ISRP column with 67 mM potassium phosphate buffer of pH 7.4 and ionic strength of 0.17 as the mobile phase. The luminol-H(2)O(2)-Co(2+) system was employed in the chemiluminescence detection. The detection was highly specific for oxacillin in the presence of cefoperazone. Although both drugs in HSA solutions co-eluted in the same region in HPFA, cefoperazone did not interfere with the determination of unbound concentration of oxacillin. In the solution of 100 microM HSA and 11.33 micro M oxacillin the bound percentage of oxacillin to HSA was estimated as 80.5%. Addition of 30.98 micro M cefoperazone into the HSA-equilibrated solution produced little effect on the protein binding of oxacillin. In the presence of 154.9 micro M cefoperazone, however, the bound percentage of oxacillin was significantly reduced. This specific method could be applied to the investigation of drug-drug interaction in protein binding.

A Novel Spectrophotometric Method for the Determination Oxacillin Sodium

“…Numerous analytical methods have been reported in the scientific literature for the determination of oxacillin sodium. These methods are based on Spectrophotometric (1), ion exchange (2), photometric extraction (3), potentiometric (4) (HPLC) (5)(6)(7)(8). The determination in biological fluids normally requires the use of trace analysis techniques such as High Performance Liquid Chromatography (HPLC), Liquid Chromatography (LC), Capillary Electrophoresis (CE), Cyclic Voltametry, Liquid Chromatography -Mass Spectrophotometry (LC-MS), Gas Chromatography -Mass Spectrophotometry (GC-MS), Inductively Coupled Plasma -Mass Spectrophotometry.…”