Design of a Transdermal Sustained Release Formulation Based on Water-Soluble Ointment Incorporating Tulobuterol Nanoparticles

Round 1

Reviewer 1 Report

In the present study, authors have produced a transdermal formulation based on water-soluble (WS), absorption (AB) and aqueous ionic cream (AC) ointment bases incorporating tulobuterol nanoparticles and evaluated which base is suitable for preparing transdermal formulations incorporating TUL-NPs. The study objectives were carefully designed and manuscript suggests complete details of the experiment methods. Statistical parameters were also considered correctly wherever necessary. However, following few questions are still needs to be answered-

1.      1.  As the nanoparticles were dispersed in ointment system therefore solubility of methyl cellulose in ointment bases and system should be considered.

 2. Shelf life of drug in ointments should be determined. Also, degradation behaviour of nanoparticles inside the ointments should be studied.

     3. Full name of all the materials were mentioned in material section but abbreviated forms were mentioned in method section. This creates a confusion. Please introduce the abbreviations in method section as well, so that it will be easy to read.

 

Author Response

We carefully revised our manuscript according to the suggestions of the reviewer 1, and details are as follows.

 

< Q and A for Reviewer 1>

 

Q1. As the nanoparticles were dispersed in ointment system therefore solubility of methyl cellulose in ointment bases and system should be considered.

 

A1. Thank you very much for pointing this out. We used the 0.05% methyl cellulose to prepare the TUL nanoparticles, and the methyl cellulose was dissolved in the ointment at room temperature. In order to respond to the reviewer’s comment, we added the content of methyl cellulose in the Table 1. Thank you for pointing out this (Table 1).

 

 

Q2. Shelf life of drug in ointments should be determined. Also, degradation behaviour of nanoparticles inside the ointments should be studied.

 

A2. The reviewer’s comments are very important. The concentration and particle size in ointment were stabile for 1 month after preparation. In order to respond to the reviewer’s comment, we added the contents in the Discussion (line 263-268).

 

 

Q3. Full name of all the materials were mentioned in material section but abbreviated forms were mentioned in method section. This creates a confusion. Please introduce the abbreviations in method section as well, so that it will be easy to read.

 

A3. The reviewer’s comment is correct. In order to respond to the reviewer’s comment, we mentioned the full name of materials in method section (2.3. Preparation of the Ointment Incorporating TUL-NPs).

 

 

Thank you for great comments.

Author Response File: Author Response.pdf

Reviewer 2 Report

The idea behind the work is interesting, and the results supports the hypothesis, however its is extremely hard to read the manuscript.

Some of my suggestions to improve the manuscript:

·         Correct the capitalization in the title (Based)

·         Too many abbreviations in the abstract, very hard to read, The abstract does not need to be elaborated in this way, it should attract the reader to continue.

·         Line 14: 30 nm-180 nm should be 30- 180 nm

·         The last sentence in the abstract is very weak and general, please replace with a more specific one.

·         Line 123: Measurement of the TUL, do the authors mean TUL HPLC assay?? It is not clear. And usually this section is at the end of the methods, before the stat. analysis.

·         Line 132: Characteristics of the Ointment Incorporating TUL-NPs, divide the test into separate subsection, to make it easier to read.

·         Reduce wordiness; for example: “Drug Release from Ointment Incorporating TUL”, better reads : Drug Release from TUL Ointment

·         Avoid repetition, for example: Changes in the transdermal penetration… in the subtitle and in the figure

·         Line 267: Figure 4 shows the skin penetration profiles of the WS/TUL, AB/TUL, and AC/TUL ointments with or without l-menthol, and Table 3 summarizes the pharmacokinetic parameters estimated from the data for the in vitro transdermal penetration shown in Figure  4…. Rephrase , don’t repeat “Figure 4”

·         Figure 7: Add “suggested”

Author Response

We carefully revised our manuscript according to the suggestions of the reviewer 2, and details are as follows.

 

< Q and A for Reviewer 2>

 

Q1. Correct the capitalization in the title (Based).

 

A1. Thank you very much for pointing this out. We corrected the title to “Design of a Transdermal Sustained Release Formulation Based on Water-Soluble Ointment Incorporating Tulobuterol Nanoparticles” (Title).

 

 

Q2. Too many abbreviations in the abstract, very hard to read, The abstract does not need to be elaborated in this way, it should attract the reader to continue.

 

A2. The reviewer’s comment is correct. In order to respond to the reviewer’s comment, we removed the abbreviations in the abstract (Abstract).

 

 

Q3. Line 14: 30 nm-180 nm should be 30- 180 nm.

 

A3. In order to respond to the reviewer’s comment, we correct to “30-180 nm” (line 14, 247, 274).

 

 

Q4. The last sentence in the abstract is very weak and general, please replace with a more specific one.

 

A4. The reviewer’s comments are very important. In order to respond to the reviewer’s comment, we revised this sentence (line 32-34).

 

 

 

 

Q5. Line 123: Measurement of the TUL, do the authors mean TUL HPLC assay? It is not clear. And usually this section is at the end of the methods, before the stat. analysis.

 

A5. Thank you very much for pointing this out. We stated the measuring of TUL by HPLC, and the sentence moved before the Statistical Analysis (line 226-233).

 

 

Q6. Line 132: Characteristics of the Ointment Incorporating TUL-NPs, divide the test into separate subsection, to make it easier to read.

 

A6. Thank you for pointing out this. In order to respond to the reviewer’s comment, we divided these tests (2.4. Evaluation of TUL Particles, 2.5. Measurement of TUL Solubility in TUL Ointment, 2.6. Measurement of Viscosity in the Ointment, line 142-165).

 

 

Q7. Reduce wordiness; for example: “Drug Release from Ointment Incorporating TUL”, better reads : Drug Release from TUL Ointment.

 

A7. The reviewer’s comment is correct. We revised to “Drug Release from TUL Ointment” from “Drug Release from Ointment Incorporating TUL” (line 173).

 

 

Q8. Avoid repetition, for example: Changes in the transdermal penetration… in the subtitle and in the figure.

 

A8. Thank you for pointing out this. We revised this section in the subtitle (line 284, 311).

 

 

Q9. Line 267: Figure 4 shows the skin penetration profiles of the WS/TUL, AB/TUL, and AC/TUL ointments with or without l-menthol, and Table 3 summarizes the pharmacokinetic parameters estimated from the data for the in vitro transdermal penetration shown in Figure 4…. Rephrase , don’t repeat “Figure 4”.

 

A9. The reviewer’s comments are very important. We revised to “Table 3 shows the pharmacokinetic parameters estimated from the data of Figure 4” (line 314-316).

 

Q10. Figure 7: Add “suggested”.

 

A10. In order to respond to the reviewer’s comment, we revised to “Suggested mechanism for the transdermal penetration process of TUL from the ointment bases incorporating TUL-NPs and l-menthol” (Figure 7).

 

 

Thank you for great comments.

Author Response File: Author Response.pdf

Reviewer 3 Report

I have reviewed the manuscript "Design of a Transdermal Sustained Release Formulation based on water-soluble ointment incorporating Tulobuterol Nanoparticles". 

Figure 1 has 3 graphs A, B and C are not well defined. Graph D is totally different technique that either should be discussed for all the ointment types or disregarded if it is not contributing to the manuscript. 

Figure 2 doesn't provide any useful information

Figure 3, 4 and 5 show release rate and AUC. The comparison of release rate and AUC is not needed as it doesn't provide useful information. 

Table 3 indicates pharmacokinetic parameters while there are no animal data to show any pharmacokinetics data

Overall, the manuscript needs further improvement before any further review. 

Author Response

We carefully revised our manuscript according to the suggestions of the reviewer 3, and details are as follows.

 

< Q and A for Reviewer 3>

 

Q1. Figure 1 has 3 graphs A, B and C are not well defined. Graph D is totally different technique that either should be discussed for all the ointment types or disregarded if it is not contributing to the manuscript.

 

A1. The reviewer’s comment is correct. The data shows the TUL in dispersions. We prepared the ointment by using these dispersions. The graphs A-C showed the particle size frequencies, and the graph D showed the particle size by the image. We think that these data are important information for the preparation of tulobuterol ointment. Thank you very much for pointing this out.

 

 

Q2. Figure 2 doesn't provide any useful information.

 

A2. We think that these images help the reader better understand what kind of ointment was used. Taken together, we remained the images. Thank you for pointing out this.

 

 

Q3. Figure 3, 4 and 5 show release rate and AUC. The comparison of release rate and AUC is not needed as it doesn't provide useful information.

 

A3. We think that the presenting both data of release behavior and AUC will enhance the reader's understanding. From these reason, we showed these data in this study. Thank you very much for pointing this out.

  

 

Q4. Table 3 indicates pharmacokinetic parameters while there are no animal data to show any pharmacokinetics data.

 

A4. The reviewer’s comments are very important. The animal data is usefulness to evaluate these ointments, although we don’t have the data. Therefore, we added the importance to measure the pharmacokinetics data using animal model in the further. Thank you very much for pointing this out (line 468-470).

 

 

Thank you for great comments.

Author Response File: Author Response.pdf

Reviewer 4 Report

Dear Authors,

I found this manuscript interesting, but I have several comments:

1. Why did you make semi-solid formulations with tulobuterol if there is a commercial transdermal patch with this active ingredient (CA-TUL tape, Hokunalin® Tape)? What prompted such a study, if the commercial preparation is effective and used in practice? Maybe it should be mentioned in the Introduction? Lines 41–48
2. I suggest indicating in the Drug release and Penetration methods, at what time points were the samples of tulobuterol taken for analysis. Line 160, 175
3. I suggest changing In Vitro Transdermal Penetration of Ointment Incorporating TUL to Ex Vivo Transdermal Penetration of Ointment Incorporating TUL. This means changing the term in vitro to ex vivo in skin penetration studies.
4. I propose to unify the x- and y-axis scales of Figure 1.
5. I suggest using either µm or nm in Table 2.
6. I propose to unify the y-axis scales in Figure 3 (A, B, C).
7. I propose to unify the y-axis scales in Figure 3 (D, E, F).
8. I propose to unify the y-axis scales in Figure 4 (A, B, C).
9. I propose to unify the y-axis scales in Figure 4 (D, E, F).

 

Author Response

We carefully revised our manuscript according to the suggestions of the reviewer 4, and details are as follows.

 

< Q and A for Reviewer 4>

 

Q1. Why did you make semi-solid formulations with tulobuterol if there is a commercial transdermal patch with this active ingredient (CA-TUL tape, Hokunalin® Tape)? What prompted such a study, if the commercial preparation is effective and used in practice? Maybe it should be mentioned in the Introduction? Lines 41–48.

 

A1. The reviewer’s comment is correct. It is important to design the nanomedicines in transdermal formulation. We selected the tulobuterol as a model drug, since the tulobuterol transdermal formulation is widely used in the clinic, and aimed to develop a transdermal sustained release formulation based on nanoparticles. In order to respond to the reviewer’s comment, we added the content in the Introduction (line 73-75).

 

 

Q2. I suggest indicating in the Drug release and Penetration methods, at what time points were the samples of tulobuterol taken for analysis. Line 160, 175.

 

A2. The reviewer’s comments are very important. The sample solution was withdrawn from the reservoir chamber at 0.5, 1, 3, 6 and 24 h. In order to respond to the reviewer’s comment, we added the content in the Materials and Methods (line 180-197).

 

 

Q3. I suggest changing In Vitro Transdermal Penetration of Ointment Incorporating TUL to Ex Vivo Transdermal Penetration of Ointment Incorporating TUL. This means changing the term in vitro to ex vivo in skin penetration studies.

 

A3. Thank you for pointing out this. In order to respond to the reviewer’s comment, we revised to “ex vivo” from “in vitro”.

 

 

Q4. I propose to unify the x- and y-axis scales of Figure 1.

 

A4. In order to respond to the reviewer’s comment, we unified the x- and y-axis scales of Figure 1A and 1B. On the other hand, Figure 1C was provided by the dynamic light-scattering analyzer NANOSIGHT LM10. Therefore, the scale could not unify (Figure 1).

 

 

Q5. I suggest using either µm or nm in Table 2.

 

A5. The reviewer’s comments are very important. We presented as “µm” (Table 2).

 

 

Q6. I propose to unify the y-axis scales in Figure 3 (A, B, C). I propose to unify the y-axis scales in Figure 3 (D, E, F). I propose to unify the y-axis scales in Figure 4 (A, B, C). I propose to unify the y-axis scales in Figure 4 (D, E, F).

 

A6. Thank you very much for pointing this out. We attempted to unify the y-axis scales in the Figure 3 and 4, however, the changes cause unclear the differences in each ointment group. Therefore, we remained the graph scale. Thank you for pointing out this.

 

 

Thank you for great comments.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

The quality of this manuscript is limited. I don't see novelty for publication in this journal. 

Author Response

We carefully revised our manuscript according to the suggestions of the reviewer 3, and details are as follows.

 

< Q and A for Reviewer 3>

Q1. The quality of this manuscript is limited. I don't see novelty for publication in this journal.

 

A1. Thank you very much for pointing this out. In this study, we found that the water-soluble-base incorporating TUL nanoparticle and l-menthol was the best among those assessed in this study. Furthermore, the pathway using caveolae-mediated endocytosis was related to the skin penetration of TUL nanoparticles in the TUL water-soluble ointment with l-menthol. We have been studied for nanomedicine, and have been involved in the publication of many papers for nanomedicine as the author and reviewer (more than 100 papers). Against this background, we think that these findings are usefulness to design the transdermal sustained release formulation based on TUL nanoparticles, and we do not believe that this paper is less novel. We hope that you will appreciate the importance of the results of this research in previous studies on nanomedicines. Thank you for reviewing.

 

 

Thank you for reviewing.

Author Response File: Author Response.pdf