The solution stability of vancomycin in the presence and absence of sodium carboxymethyl starch

The purpose of this work was to study the potential for drug-excipient interactions to alter the stability of pharmaceutical drug products. Previous studies have demonstrated the interactions between glycopeptide antibiotics (e.g. vancomycin) and sodium carboxymethyl starch (NaCMS). A key objective of this work was to determine the effect of NaCMS binding on the solution stability of the glycopeptide antibiotic, vancomycin. The solution stability of vancomycin was studied under various pH and ionic strength conditions at physiological temperature (37 degrees C). A stability-indicating HPLC method specific for vancomycin vias developed and validated for use in this research. Vancomycin stability was evaluated alone and in the presence of NaCMS in various buffers from pH 2 to 9, and in simulated gastric and intestinal fluids to determine if NaCMS influences the degradation rate of vancomycin in solution. Results indicated that the pH stability profile of vancomycin at 37 degrees C from pH 2 to 7 was slightly stabilized in the presence of NaCMS at the pH and ionic strength conditions where binding to NaCMS was shown to occur. (C) 1998 Elsevier Science B.V. All rights reserved.