Using Hypurity C18 column poor chromatography click here was observed. Good response was observed with waters Atlantis, HILIC, 50 × 2.1 mm, 3 μm, was selected as the analytical column connected with Guard column Waters Atlantis, HILIC, 10 × 2.1 mm, 3 μm. It gave satisfactory peak shapes for both Acamprosate and Acamprosate

D12. Flow rate of 0.25 mL/min without splitter was utilized and reduced the run time to 3.0 min. Both Drug and IS were eluted with shorter time at 2.1 min. For an LC-MS/MS analysis, utilization of stable isotope-labeled or suitable analog drugs as an internal standard proves helpful when a significant matrix effect is possible. In our case, Acamprosate D12 was found to be best for the present purpose. The column temperature was adjusted to 40 °C. Injection volume of 20 μL sample is adjusted for better ionization and chromatography. During extraction stage different extraction procedures like PPT (protein precipitation), LLE (liquid–liquid extraction), and SPE (solid phase extraction). We found ion suppression effect in protein precipitation method for drug and internal standard. Further, we tried with SPE and LLE. Out of all, we observed that SPE is suitable for extraction LGK-974 nmr of drug and IS. Autosampler wash is optimized as 80% methanol. Several compounds were investigated to find a suitable IS, and finally Acamprosate D12 found the most

appropriate internal standard for the present purpose. There was no significant effect of IS on analyte recovery, sensitivity Linifanib (ABT-869) or ion suppression. High recovery and selectivity was observed in the solid phase extraction method. These optimized detection parameters, chromatographic conditions and extraction procedure resulted in reduced analysis time with accurate and precise detection of Acamprosate in human plasma. A thorough and complete method validation of Acamprosate in human plasma was done following USFDA guidelines.13 The method was validated for selectivity, sensitivity, matrix effect, linearity,

precision and accuracy, recovery, dilution integrity, reinjection reproducibility and stability. There is no interference observed for Acamprosate and Acamprosate D12 at their retention time in blank plasma (Fig. 4) and LOQ (Fig. 5). These interferences are within the acceptance criteria for all six lots of blank samples. The LLOQ for Acamprosate was 1.00 ng/mL. The intra-run, inter-run precision and accuracy of the LLOQ plasma samples containing Acamprosate was 3.56 and 102.00% and 2.0 and 102.21%, respectively. All the values obtained below 1.00 ng/mL for Acamprosate were excluded from statistical analysis as they were below the LLOQ values validated for Acamprosate. The CV % of ion suppression/enhancement in the signal was found to be 1.0% at MQC level for Acamprosate indicating that the matrix effect on the ionization of analyte is within the acceptable range under these conditions.