Stability of vancomycin in SyrSpend SF

Vancomycin is administered orally for the treatment of pseudomembranous colitis induced by Clostridium difficile. Vancomycin is marketed for this purpose by ViroPharma as VANCOCIN in 125-mg and 250-mg capsules. The need for other dose form options for those patients who cannot take capsules has led compounding pharmacies to seek other alternatives, namely oral solutions and suspensions. Additionally, some patients are unable to use suspending agents containing alcohol or sorbitol. The objective of this study was to determine the stability of vancomycin in SyrSpend SF, a suspending agent containing neither sorbitol nor alcohol. The studied sample was compounded into a 50-mg/mL suspension and stored in a low-actinic plastic bottle at temperatures between 2 degrees C and 8 degrees C. Six samples were assayed at each time point out to 90 days by a stability-indicating high-performance liquid chromatography method. The method was validated for its specificity through forced-degradation studies. The sample remained within 90% to 110% of the initial concentration throughout the course of the study. Based on data collected, the shelf life of this product is at least 90 days when refrigerated and protected from light. Based on the final potency data at day 90, the beyond-use date may be longer, but 90 days was the limit of this study.