Liquid chromatographic assay for dicloxacillin in plasma

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Vol. 805; no. 2; pp. 353 - 356
• Main Authors: Alderete, Oscar, González-Esquivel, Dinora F, Misael Del Rivero, L, Castro Torres, Nelly
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-06-2004; Elsevier Science
• Subjects: Analysis; Analytical, structural and metabolic biochemistry; Anti-Bacterial Agents - blood; Anti-Bacterial Agents - pharmacokinetics; Biological and medical sciences; Chromatography, High Pressure Liquid - methods; Dicloxacillin; Dicloxacillin - blood; Dicloxacillin - pharmacokinetics; Fundamental and applied biological sciences. Psychology; General pharmacology; Humans; Medical sciences; Pharmacology. Drug treatments; Reproducibility of Results; Sensitivity and Specificity; Spectrophotometry, Ultraviolet; Therapeutic Equivalency; Dicloxacillin; Human; Biological fluid; Temperature; β-Lactams; HPLC chromatography; Liquid chromatography; Evaporation; Blood plasma; Penicillin derivatives; Antibiotic; Ultraviolet detector; Dichloromethane; Antibacterial agent; Pharmacokinetics; Quantitative analysis; Methanol
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/j.jchromb.2004.03.006

A simple high-performance liquid chromatographic method for the determination of dicloxacillin in plasma has been developed. The method only requires 0.5
ml of plasma, phosphate buffer solution (pH=4.7), acidification with 0.5N hydrochloride acid and liquid extraction with dichloromethane. Posterior evaporation of organic under nitrogen steam and redissolution in mobile phase is carried out. The analysis was performed on a Spherisorb C
18 (5
μm) column, using methanol–0.05
M phosphate buffer, pH=4.7 (75:25; v/v) as mobile phase, with ultraviolet detection at 220
nm. Results showed that the assay is sensitive: 0.5
μg/ml. The response is linear in the range of 0.5–10
μg/ml. Maximum inter-day coefficient of variation was 12.4%. Mean extraction recovery obtained was 96.95%. Stability studies showed that the loss was not higher than 10%, samples are stable at room temperature for 6
h, at −20
°C for 2 months, processed samples were stable at least for 24
h and also after two freeze–thaw cycles. The method has been used to perform pharmacokinetic and bioequivalence studies in humans.