title: Liquid chromatographic assay for dicloxacillin in plasma.
abstract: 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 C18 (5 microm) 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 microg/ml. The response is linear in the range of 0.5 - 10 microg/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 Celsius 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.
authors.affiliation: Biophade SC, México D.F., Mexico.
authors.forename: Oscar
authors.initials: O
authors.lastname: Alderete
authors.forename: Dinora F
authors.initials: DF
authors.lastname: González-Esquivel
authors.forename: L Misael
authors.initials: LM
authors.lastname: Del Rivero
authors.forename: Nelly
authors.initials: N
authors.lastname: Castro Torres
mesh_terms: D000900:Anti-Bacterial Agents / Q000097:blood* / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004009:Dicloxacillin / Q000097:blood* / Q000493:pharmacokinetics; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet; D013810:Therapeutic Equivalency
chemical_list: D000900:Anti-Bacterial Agents; D004009:Dicloxacillin