MEASUREMENT AND PHARMACOKINETICS OF ACETYLSALICYCLIC ACID BY A NOVEL HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ASSAY

  • 1 January 1980
    • journal article
    • research article
    • Vol. 2  (4) , 365-372
Abstract
Plasma acetylsalicylic acid [ASA] and salicylic acid [SA] [analgesics] are assayed by a specific, rapid and sensitive high performance liquid chromatographic procedure. The plasma samples are treated with physostigmine to inhibit esterase activity that otherwise will promote enzymatic hydrolysis of ASA to SA. Conditions are chosen such that the total in vitro hydrolysis of ASA is minimized to < 5%. Plasma samples are deproteinated with methylcyanide. ASA and SA are separated by elution with a mixture of methanol, acetic acid and water on a reversed-phase octadecyl silane column and detected by UV absorption. Quantitation is achieved by measuring absolute peak heights. Recovery and repeatability studies are good. No interference was observed when 50 drugs were present in the various plasma samples. Concentrations of ASA and SA can be obtained within 20 min of receipt of the blood specimens. Pharmacokinetic parameters obtained by this method after a single oral dose of 900 mg soluble, effervescent ASA in normal healthy subjects suggest that absorption, distribution and elimination of ASA are rapidly occurring events.