ADSORPTION OF MEXILETINE ONTO ACTIVATED-CHARCOAL IN MACROGOL-ELECTROLYTE SOLUTION

Adsorption studies in vitro of mexiletine onto activated charcoal were performed in macrogol (polyethylene glycol)-electrolyte solution (PEG -ELS) and JP XII disintegration medium No. 2 (second medium). Mexileti ne was adsorbed more extensively onto activated charcoal in PEG-ELS th an that in JP XII second medium. The maximum adsorptive capacity of ac tivated charcoal for the drug was 328 and 284 mg per gram of charcoal in PEG-ELS and JP XII second medium, respectively. In addition, the eq uilibrium constant of activated charcoal estimated according to the La ngmuir equation was 0.079 and 0.034 1 per gram of charcoal in PEG-ELS and JP XII second medium, respectively. Adsorption of mexiletine onto activated charcoal was decreased by omitting macrogol, sodium sulfate or sodium bicarbonate from a standard PEG-ELS formulation. Oral activa ted charcoal will be useful in combination with whole bowel irrigation with PEG-ELS in mexiletine overdose because of its excellent adsorbab ility in the solution.