ABSTRACT
The USP monograph describes an HPLC method for seven impurities in the amiodarone drug substance using a L1 column, 4.6mm×150mm, 5µm packing (PF listed ODS2 GL-Science, Inertsil column) at 30°C with detection at 240nm. The standard contains 0.01mg/mL of amiodarone, and USP specified impurities D and E with a resolution requirement of NLT 3.5 between peaks D and E. Impurities in a 5mg/mL sample are quantitated against the standard. Impurity A peak elutes just before peak D. We observed two problems with the method; the column lot-to-lot variability resulted in unresolved A, D, and E peaks, and peak D in the sample preparation eluted much later than that in the standard solution. Therefore, optimization experiments were conducted on the USP method following the QbD approach with Fusion AE™ software (S-Matrix Corporation). The resulting optimized conditions were within the allowable changes per USP ã621ã. Lot-to-lot variability was negligible with the Atlantis T3 (Waters Corporation) L1 column. Peak D retention time remained constant from standard to sample. The optimized method was validated in terms of accuracy, precision, linearity, range, LOQ/LOD, specificity, robustness, equivalency to the USP method, and solution stability. The QbD based development helped in generating a design space and operating space with knowledge of all method performance characteristics and limitations and successful method robustness within the operating space.
Subject(s)
Amiodarone/analysis , Anti-Arrhythmia Agents/analysis , Chromatography, High Pressure Liquid/methods , Drug Contamination , Technology, Pharmaceutical/methods , Amiodarone/standards , Anti-Arrhythmia Agents/standards , Calibration , Chromatography, High Pressure Liquid/standards , Drug Stability , Guidelines as Topic , Limit of Detection , Molecular Structure , Quality Control , Reference Standards , Reproducibility of Results , Technology, Pharmaceutical/standardsABSTRACT
We conducted a series of liquid-culture experiments to begin to evaluate the abilities of gaseous sources of nitrogen and phosphorus to support biodegradation of polycyclic aromatic hydrocarbons (PAHs). Nutrients examined included nitrous oxide, as well as triethylphosphate (TEP) and tributylphosphate (TBP). Cultures were established using the indigenous microbial populations from one manufactured gas plant (MGP) site and one crude oil-contaminated drilling field site. Mineralization of phenanthrene was measured under alternative nutrient regimes and was compared to that seen with ammoniacal nitrogen and PO(4). Parallel cultures were used to assess removal of a suite of three- to five-ring PAHs. In summary, the abilities of the different communities to degrade PAH when supplemented with N(2)O, TEP, and TBP were highly variable. For example, in the MGP soil, organic P sources, especially TBP, supported a considerably higher degree of removal of low-molecular-weight PAHs than did PO(4); however, loss of high-molecular-weight compounds was impaired under these conditions. The disappearance of most PAHs was significantly less in the oil field soil when organophosphates were used. These results indicate that the utility of gaseous nutrients for PAH bioremediation in situ may be limited and will very likely have to be assessed on a case-by-case basis.
