tailieunhanh - Drugs and Poisons in Humans - A Handbook of Practical Analysis (Part 42)

Introduction: β-Lactum antibiotics constitute an important class of antibacterial agents being used extensively for both humans and food-producing animals to treat or prevent infections. The drugs occasionally cause human deaths due to anaphylactic shock during medical treatments, especially when they are parenterally administered without their prior intracutaneous tests. These cases are usually handled as medical accidents (malpractice), and subjected to autopsies and analysis of the drugs used. These antibiotics are composed of cephems ( Table ) and penicillins ( Table ), which are naturally occurring or semi-synthetic. Furthermore, two subclasses of cephem antibiotics are cephalosporins and cephamycins (. | 10 p-Lactam antibiotics by Yuko Ito and Hisao Oka Introduction p-Lactum antibiotics constitute an important class of antibacterial agents being used extensively for both humans and food-producing animals to treat or prevent infections. The drugs occasionally cause human deaths due to anaphylactic shock during medical treatments especially when they are parenterally administered without their prior intracutaneous tests. These cases are usually handled as medical accidents malpractice and subjected to autopsies and analysis of the drugs used. These antibiotics are composed of cephems Table and penicillins Table which are naturally occurring or semi-synthetic. Furthermore two subclasses of cephem antibiotics are cephalosporins and cephamycins Table . The primary structural difference between the cephalosporins and cephamycins is the methoxy group substituted for the .-hydrogen in the 7-position on the p-lactam ring. In this chapter methods for simultaneous analysis of 6 kinds of penicillins and of 4 kinds of cephems by HPLC-UV are described. HPLC-UV analysis of penicillin antibiotics 1 Reagents and their preparation Benzylpenicillin phenoxymethylpenicillin ampicillin cloxacillin dicloxacillin nafcillin and ß-hydroxyethyltheophylline can be purchased from Sigma St. Louis MO USA . Acetonitrile is of HPLC grade and water is purified with a Milli-RO Q water purification system Millipore Bedford MA USA . A working internal standard IS solution is prepared daily with purified water to give a concentration of 20 pg mL of ß-hydroxyethyltheophylline. Calibration standard are prepared daily with drug-free human serum covering the range of pg mL. 1 mM Ammonium acetate buffer solution pH mg of ammonium acetate is dissolved in purified water to prepare 1 L solution and adjusted to pH with either ammonia water solution or acetic acid solution. M Tetrabutylammonium hydrogen sulfate solution g of tetrabutylammonium hydrogen sulfate