INTERACTION OF SUCRALFATE WITH ANTIBIOTICS USED FOR SELECTIVE DECONTAMINATION OF THE GASTROINTESTINAL-TRACT

The interactions of sucralfate with colistin sulfate, with tobramycin sulfate, and with amphotericin B were studied. Sucralfate 500 mg was a dded to 40 mL of distilled water adjusted to pH 3.5 with hydrochloric acid. Stock solution of one of the three antibiotics was added to give a final colistin concentration of 50 mg/L (as the sulfate salt), fina l tobramycin concentration of 50 mg/L (as the sulfate salt), and final amphotericin B concentration of 25 mg/L. Samples were removed from ea ch sucralfate-antibiotic mixture at 0, 5, 10, 15, 30, 45, 60, and 90 m inutes and analyzed for antibiotic concentration by high-performance l iquid chromatography (colistin), enzyme immunoassay (tobramycin), and spectrophotometry (amphotericin B). To determine if any interaction wa s reversible, the mixtures were stored for 90 minutes without sampling , the pH was adjusted to 6.5-7.0, and samples were removed and analyze d. All tests were performed in triplicate, and the temperature was mai ntained at 25-degrees-C. Significant drug loss was observed starting a t five minutes for each antibiotic-sucralfate mixture. This effect was not reversible in the less acidic environment. The concentrations of colistin, tobramycin, and amphotericin B declined rapidly when each dr ug was combined separately with sucralfate.