tailieunhanh - Drugs and Poisons in Humans - A Handbook of Practical Analysis (Part 35)

Introduction: Acetaminophen (paracetamol, APAP) ( Figure ) has been being used as an excellent analgesic-antipyretic for a long time, and is included as an ingredient in many over-the-counter drugs of analgesics and cold drugs. However, when APAP is ingested in large amounts, it was reported to cause liver disorders [1]. For analysis of APAP, HPLC [2–18], LC/MS [19], LC/MS/MS [20], GC [21], GC/MS [22, 23] and capillary electrophoresis [24, 25] are being used. Among the methods, HPLC is most popular for its analysis. In this chapter, HPLC methods for analysis of APAP and its metabolites are presented. . | Acetaminophen paracetamol by Einosuke Tanaka Introduction Acetaminophen paracetamol APAP Figure has been being used as an excellent analgesic-antipyretic for a long time and is included as an ingredient in many over-the-counter drugs of analgesics and cold drugs. However when APAP is ingested in large amounts it was reported to cause liver disorders 1 . For analysis of APAP HPLC 2-18 LC MS 19 LC MS MS 20 GC 21 GC MS 22 23 and capillary electrophoresis 24 25 are being used. Among the methods HPLC is most popular for its analysis. In this chapter HPLC methods for analysis of APAP and its metabolites are presented. O Figure NHCOCHs OH Structure of acetaminophen. HPLC analysis of APAP and its metabolites in serum 18 Reagents and their preparation APAP Sigma St. Louis MO USA is dissolved in methanol to prepare 1 mg mL solution. Theophylline internal standard IS Sigma is dissolved in 6 perchloric acid aqueous solution to prepare 10 mg mL solution. APAP and its metabolitesa APAP-glucuronide and APAP-N-sulfate are dissolved in methanol to prepare 1-200 pg mL solutions for calibration curves. HPLC conditions Column a reversed phase columnb C18 150 x mm i. d. particle diameter 5 pm Supelco Bellefonte PA USA . Mobile phase mM sodium sulfate solution pH c acetonitrile 93 7 v v . Detection wavelength 254 nm flow rate mL min column oven temperature 30 C. Springer-Verlag Berlin Heidelberg 2005 336 Acetaminophen paracetamol Procedure i. A 10-pLd aliquot of serum and 20 pL IS solution6 are placed in a centrifuge tube. ii. The tube is vortex-mixed for 5 s. iii. It is centrifuged at 1 700 g and 4 C for 5 min. iv. The supernatant fraction is transferred to a clean glass test tube. v. A 10-pL aliquot of it is injected into HPLC. vi. The various concentrations of the standard solutions are processed according to the above procedure. Assessment of the method Figure shows an HPLC chromatogram for an extract of rat serum to which APAP and its .