Integral UV Spectrophotometric Methods for Determination of Clopidogrel Bisulphate and Metamizole Sodium in Rinse Waters from Industrial Equipment

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript "Integral UV-Spectrophotometric Methods of Determination of 2 Clopidogrel Bisulphate and Metamizole Sodium in Rinse Waters from Industrial Equipment" describes the use of integral UV methods for the determination of two drugs produced in all the world. 

The aim of the work and the procedures are properly described. Plese find below my comments:

1. It would be useful having a figure with the structure of the molecules.

2. Row 41. Row 41 “As can be seen from the figure, the absorption maxima at 270 and 276 nm have too low 41 absorbability, so the sensitivity of direct spectrophotometric determination is low” The authors refer to the figure 1 where wavelength vs absorbance graph is reported. Why do they write “absorbability”? Do the refer to absorbance (as shown in the graph) or to molar aborptivity? Moreover, if the wavelength of interest is > of 250 nm, it would be preferable to show the corresponding range of absorbance in order to not include very high values (i.e. 3) out of the linearity of Lambert-Beer law.  The same for figure 2

3. Please adjust the value of % standard deviation in tables 4 and 5.

 

Author Response

Dear reviewer, please refer to the attached file.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The article is devoted to the UV-spectrophotometric methods of  clopidogrel bisulphate and metamizole sodium determination. It looks like the research has been done correctly. I can recommend this manuscript for publication in the Spectroscopy Journal. However, I have some comments, in the details:

1. The authors assume linearity from 1-100 mg/l, because above 100 mg the absorbance exceeds 2.5-3 units. Analysing the graphs in Figures 1 and 2, it can be seen that at concentrations of 100 mg, the curves in the ranges 210-230 nm for clopidogrel bisulphate and 220-245 nm for metamizole sodium, the absorbance exceeds 2.5 units, and in my opinion the graphs are not reliable. Moreover, the author should provide a line graph with standard deviation.

2. The author assumes that the pH of the standard solutions and the real solutions are the same. Has the pH of the solutions been measured? Has the effect of pH on the UV absorbance curves of the compounds been studied? The author also wrote “Therefore, the aim of this work is to develop integral UV-spectrophotometric methods for determining clopidogrel bisulphate and metamizole sodium directly in industrial equipment cleaning rinse waters without using organic solvents and monitoring the solution pH.”. Does the author know what the pHs of such solutions are?

3. Selected absorption curves should be included in the supplementary material to confirm the test results with respect to accuracy, precision, repeatability and interfering effect of excipients.

4. There are a few typing errors and some sentences need editing.

Author Response

Dear reviewer, please refer to the attached file.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript have been corrected. I can recommend this manuscript for publication in the Spectroscopy Journal. However, I have one more comment, the discussion and conclusions are too short, disappointing and need to be developed. 

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Author Response

Dear reviewer, thank you for your comment.

"The manuscript have been corrected. I can recommend this manuscript for publication in the Spectroscopy Journal. However, I have one more comment, the discussion and conclusions are too short, disappointing and need to be developed."

According to your suggestion, the discussion and the conclusion sections were extended. The comparison of the proposed method with other existing spectrophotometric methods was added. The advantages of the proposed method were explicitly highlighted.