Determination of aspirin and salicylic acid in transdermal perfusates

• Published in: Journal of chromatography. B, Biomedical sciences and applications Vol. 707; no. 1; pp. 322 - 327
• Main Authors: McMahon, Gillian P, O' Connor, Shane J, Fitzgerald, Desmond J, le Roy, Sylvie, Kelly, Mary T
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 10.04.1998; Elsevier Science
• Subjects: Analysis; Animals; Anti-Inflammatory Agents, Non-Steroidal - analysis; Aspirin; Aspirin - analysis; Biological and medical sciences; Calibration; Chromatography, High Pressure Liquid; General pharmacology; Indicators and Reagents; Medical sciences; Mice; Pharmacology. Drug treatments; Reference Standards; Reproducibility of Results; Salicylates - analysis; Salicylic Acid; Skin - chemistry; Salicylic acid; Aspirin; Non steroidal antiinflammatory agent; Analgesic; Transdermal system; Perfusion; Antipyretic; HPLC chromatography; Dosage form; Acetylsalicylic acid; Prodrug; Salicylates; Quantitative analysis
• ISSN: 0378-4347; 1387-2273
• DOI: 10.1016/S0378-4347(97)00580-X

A high-performance liquid chromatographic (HPLC) method has been developed for the simultaneous determination of aspirin and salicylic acid in transdermal perfusates. The compounds were separated on a C 8 Nucleosil column (5 μm, 250×4.6 mm) using a mobile phase containing a mixture of water–acetonitrile–orthophosphoric acid (650:350:2, v/v/v) and a flow-rate of 1 ml/min. The transdermal samples were in phosphate-buffered saline (PBS) and could be injected directly onto the HPLC system. The method was reproducible with inter-day R.S.D. values of no greater than 3.46 and 2.60% for aspirin and salicylic acid, respectively. The method was linear over the concentration range 0.2–5.0 μg/ml and had a limit of detection of 0.05 μg/ml for both compounds. For certain samples, it was necessary to ensure that no transmembrane leakage of the aspirin prodrugs had occurred. In these cases, a gradient was introduced by increasing the acetonitrile content of the mobile phase after the salicylic acid had eluted. The method has been applied to the determination of aspirin and salicylic acid in PBS following in vitro application of the compounds to mouse skin samples.