Development and Characterization of Long-Acting Injectable Risperidone Microspheres Using Biodegradable Polymers: Formulation Optimization and Release Kinetics
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors- Why was the specific grade of PLGA (85:15) chosen, and how does this composition influence the degradation rate and drug release profile?
- Can the authors provide the purity levels of the chemicals used, especially PLGA and risperidone, to ensure consistency and reproducibility?
- Was the choice of pH 4.0 buffer during washing critical for encapsulation efficiency? How does it compare with other pH values?
- Discussing these two recent studies on emulsification will enhance the depth of the article. Please provide a detailed explanation of these two studies.
An experimental investigation of oil-water flow in a serpentine channel
https://doi.org/10.1016/j.ijmultiphaseflow.2020.103327
Experimental investigation of viscous oil-water flows in pipeline
https://doi.org/10.1016/j.petrol.2016.05.010
- Could the authors explain why the encapsulation efficiency remained consistently high across all formulations despite varying PLGA ratios?
- How was the pore size on the microsphere surfaces measured, and what implications might these pores have on the drug release mechanism?
- The PXRD results suggest an amorphous transformation of risperidone. Could the authors provide additional evidence, such as DSC (Differential Scanning Calorimetry) data, to confirm this transformation?
- Was there any in vivo testing planned to validate the observed in vitro release profiles?
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors studied the development of nanoscale sphere using poly (lactic-co-glycolic acid) and its release kinetics. The authors found that the size of nanoscale sphere depend on the risperidone-to-PLGA ratios. These nanoscale spheres with different sizes had different risperidone released. This information is helpful for the readers working on the drug delivery system. However, there are some concerns about the introduction and the results. If the authors appropriately revise the manuscript, this study will meet the criteria for the publication in Processes.
Comment 1: What is the broad peak in Figure 2? If the material is amorphous, I guess that there are no XRD peaks.
Comment 2 Please show the reason why the experimental data do not agree with the predicted ones. In addition, I wonder how the authors predicted the time dependence of risperidone released.
Comment 3: Did the authors measured the histogram of spheres? I am worried about the relationship between the size distribution of spheres and the performance.
Comment 4: In the beginning of the introduction, the authors commented on only drug delivery, which is too narrow. The sphere structure the authors paid attention to is widely studied in various fields. Therefore, the authors should start the background of nanoscale sphere structure (merit of nanoscale sphere structure -> drug delivery as one of the application of sphere structure…). For example, there are important studies about nanoscale sphere structure: Fe3O4 nanosphere resistive switching memory (Sci. Technol. Adv. Mater. 21, 195 (2020).)., GeSn nanosphere photoemitter (Appl. Phys. Lett. 91, 013109 (2007).), etc. I recommend the authors’ commenting on these nanoscale sphere studies and citing the related references including the recommended ones.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsEverything was cleared. This study is worth publishing.
