Measurement of albuterol in guinea pig serum by high performance liquid chromatography with fluorescence detection

A sensitive, simple and reproducible high performance liquid chromatographic method for detecting and quantifying albuterol in guinea pig serum is described. A structurally related compound, bamethan, was used as an internal standard. The method employs ion-pair extraction with di(2-ethylhexyl)phosphate followed by chromatography on a Zorbax SB C18 reversed-phase column. Fluorescence detection was used to identify the compounds of interest. The calibration curve was linear between 1 and 50 ng/mL albuterol hemisulfate salt (0.83 and 41.50 ng/mL albuterol base), and the limit of detection for a 1 mL sample was 1 ng/mL albuterol hemisulfate salt (0.83 ng/mL albuterol base). Serum levels of albuterol were quantified from guinea pigs that had received the drug by continuous subcutaneous infusion at a dose of 0.2 mg/kg/day for 1, 5 or 10 days, or 10 days followed by a 24 h washout period.