Sitaramaraju Yarramraju, Riadi Adil, D'Autry Ward, Wolfs Kris, Hoogmartens Jos, Van Schepdael Ann, Adams Erwin
Laboratory for Pharmaceutical Analysis, Faculty of Pharmaceutical Sciences, K.U.Leuven, Leuven, Belgium.
J Pharm Biomed Anal. 2008 Sep 10;48(1):113-9. doi: 10.1016/j.jpba.2008.05.015. Epub 2008 May 21.
Residual solvents (RS) are volatile organic chemicals that are used or produced during the manufacturing process of drug substances or excipients. The European Pharmacopoeia (Ph. Eur.) limits the amount of RS in pharmaceuticals, considering the International Conference on Harmonization (ICH) of Technical Requirements for Registration of Pharmaceuticals for Human Use guidelines for RS. According to the Ph. Eur. general method, water insoluble samples may be analyzed using DMF as dilution solvent at high equilibration temperatures such as 105 degrees C. This could be problematic in the case of antibiotics, many of which are water insoluble and temperature sensitive. Moreover, antibiotics are complex in nature and beside RS, one can expect several other volatile impurity peaks in the chromatogram. In this study, the Ph. Eur. method for RS analysis was evaluated for selected groups of antibiotics. An alternative dilution medium was proposed (DMSO-water), which offers optimum sensitivity while working at lower equilibration temperatures such as 80 degrees C. The optimized method was investigated for precision, accuracy, linearity and detection limits.
