Hi, My Compound is an Mesylate salt, I have identified 5 impurities and Synthesized. Out of which three compounds are neutral compounds (i.e not in the form of salts), one compound is mesylate salt (like API) and other one is Free base form. Now If do Related substances analysis for the Final product, how I have to take the weight for a given concentration. For the three non-salt compounds I can take as such weight (i.e No molecular weight correction). but for the remaining two compounds (i.e one is freebase and other one is Mesylate salt) How the weight should be taken?. (i.e either both as freebase?)
Dear Sir. Concerning your issue about determination of Mesylate salt by HPLC . A simple, rapid, accurate, precise and reproducible reverse phase high performance liquid chromatographic method has been developed for the estimation of gemifloxacin mesylate in bulk and pharmaceutical formulations. The quantification was carried out using cyberlab capcell pak, ODS C18 (250 × 4.6 mm i.d., 5 μm particle size) column in an isocratic mode,
with mobile phase comprising Buffer (KH2PO4 with pH 6.8): acetonitrile in the ratio of 80:20 (%v/v).The flow rate was at 1.2 mL/min and the detection was carried out at 265 nm. The retention time of the drug was found to be 7.47 min and the method produced linear response in the concentration range of 25-150 μg/mL (R~0.99986). The recovery studies were also carried out and % RSD from reproducibility was found to be 0.82. A gradient reversed phase high performance liquid chromatography (RP-HPLC) method has been developed and validated for the determination for eight related substances of Dabigatran Etexilate Mesylate. The successful chromatographic separation of Dabigatran Etexilate from its related substances was achieved on octadecyl silane chemically bonded to porous silica particles stationary phase i.e Inertsil ODS-4, 250mm x 4.6mm, i.d., 5µ column maintained at temperature at 25°C by using phosphate buffer pH 3.0 and acetonitrile as mobile phases A & B respectively. Wavelength for UV detection: 220nm, flow rate: 1.0ml/min and Injection volume: 10µl. The performance of the method was validated according to the ICH guidelines for specificity, linearity, accuracy, precision, limit of quantification, limit of detection robustness and ruggedness and also DEM was subjected to stress conditions of thermal, hydrolysis, humidity, peroxide and photolytic to observe the degradation products. Limit of detection of impurities was in the range of 0.007%–0.008% indicating the high sensitivity of the developed method I think the following below link and the attached file may help you in your analysis:
http://www.scholarsresearchlibrary.com/articles/validation-of-stabilityindicating-reverse-phase-hplc-method-for-the-determination-of-related-substances-in-dabigatran-et.pdf
Thanks
first you take u.v spectrum of your compound so that you could know intensity of absorption your comopund
Hello Sathish, my opinion is that you can calculate the concentration on whatever basis you choose as long as it is clear in your documented method what you are doing. The most important thing is the setting of specifications around how much of the related substances are allowed to be present.
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