IMMUNOASSAY OF DIGOXIN IN HAIR

Digoxin analysis in blood is an essential tool for therapeutic drug mo nitoring in cardiology because compliance with the treatment is a crit ical issue for the patient. Unfortunately in postmortem cases brood di goxin concentration is of poor quality because there is a possible dru g redistribution in the corpse and because of digoxin-like factors pre sent in some people's blood. On the other hand, no biological fluid ca n be obtained at the autopsy. The aim of the present study was to eval uate the ability of an immunological method to determine digoxin in ha ir, in order to confirm that hair analysis can provide information on digoxin use before death. We studied 35 elderly patients who had been taking digoxin (60-250 mu g/day) for 1-5 years. Two decontamination pr ocedures were tested: washing by dichloromethane or by water and metha nol. Three extraction procedures were compared: crushing in a ball mil l and chloroform/acetone; crushing and methanol; enzymatic digestion. Immunoassays were performed by a microparticulate enzyme immunoassay. Serum digoxin levels were also assayed when sampling hair. The best re sults were obtained after decontamination with water and methanol foll owed by enzymatic digestion. Hair digoxin concentrations range from 3. 6 to 11.4 pg/mg. Those Very low concentrations are probably due to low and narrow range serum digoxin levers (0.3-1.4 ng/ml). No correlation was found between hair and blood digoxin. A forensic case is presente d with 5 pg/mg digoxin in hair. (C) 1997 Elsevier Science Ireland Ltd.