SPDS EXPERT REVIEW PANEL

C. Is there information demonstrating that the method system suitability tests and controls as specified in the SMPR worked appropriately and as expected? If no, please specify. D. Based on the supporting information, is the method written clearly and concisely? If no, please specify the needed revisions.

Answer can be found above.

As I mentioned above that, the method should be revised from the beginning. It is written not only unclear but also is not easy to follow. I also would like to mention some minor points (technical, grammatical etc.) under this section: * Firstly attached draft can be combined with the proposal in an understandable way *As the authors indicated in first page, section 3, is there any sample preparation method (extraction etc.) that buffer used for the increasing stability in this proposal (especially for real sample)? *Proposal should be checked for technical and grammatical mistakes. *All units should be converted according to the SMPR requirements (mg/g instead of ug/mL). *%RSD changed as RSD% *Several chromatograms needed to clarify our understanding. *I have some curiosity concerning to accuracy. The authors mentioned in section 7 that labeled claim was 100 mg. But the found amounts were about 82-83 mg. It means that 17-18% Relative error and it demonstrates that there was an accuracy problem. Also Lab 1 given the results from 8 replicates but other laboratories repeated 3 times. *Another point related with the finished product. As I understand that in section 6 (200 mg) and 7 (100 mg) they used different finished products which included different amounts of SAMe. *Safety instructions should be added to the proposal. *The authors should be used the symbol of micrometer instead of um (Apparatus part bullet c). *ACS grade instead of ASC grade (Reagents bullet d) *All units should be written to SI unit style mL instead of ml *In draft, transsulfuration was underlined *In draft, apparatus part bullet b, temperature should be written with using superscript letter. * Reagents, bullet a, Merck Millipore instead of Capital letters. bullet d, ACS instead of ASC, bullet f, pH instead of PH * Just wonder to know, did the authors tried -20 and -80 stability of the SAMe * What is the effect of extraction step in general, is it really necessary? * Why the authors chose gradient analysis it can be analysed isocratically? * Peak purity result should be added to the proposal. *System suitability test parameter results should be given as a table including with the products mentioned in selectivity.

* Calculation of LOD and LOQ should be demonstrated. * Solid form stability of the SAMe can be mentioned.

E. Based on the supporting information, what are the pros/strengths of the method?

The main strength of the method is, it can be used easily worldwide due to the used reagents, instrumentation etc.