Comparative Stability of Antibiotic Admixtures in Minibags and Minibottles

Abstract

With the increasing use of minibags/minibottles in intravenous admixture programs for the intermittent intravenous administration of antibiotics, a need existed for comparative stability data on these relatively concentrated unit-dose admixtures. Most admixture stability studies have involved the use of large volume infusions. Accordingly, a study was conducted to determine the stability of minibag/minibottle admixtures of frequently prescribed antibiotics. Test samples were obtained for all admixtures prepared in minibags/minibottles containing 0.9 percent normal saline and 5 percent dextrose in water and stored at 5–6 C° and 21–23 C° over a 24-hour period. All antibiotic admixtures were analyzed by a quantitative microbiological assay using an agar-gel diffusion technique. Determinations of pH were also conducted on all test samples. No significant difference in antibiotic stability was observed between minibags or minibottles. Cephalothin sodium, gentamicin sulfate, carbenicillin disodium, erythromycin gluceptate, penicillin G potassium, cefazolin sodium, rolitetracycline base and cloxacillin sodium were found to be sufficiently stable for 24-hours under the test conditions. Ampicillin sodium in a 2 percent concentration was found to be stable for 24-hours when prepared in 0.9 percent normal saline and stored at 5 C° or 21 C°. It was not possible to correlate changes in pH with antibiotic activity.