TH-NP were optimized using the design of experiments approach (DoE). A full factorial central design of five levels and three factors was applied in order to reduce the number of experiments [46]. This experimental design consisted of 16 formulations with variable factorial points (− 1/ + 1), axial points (− 1.68/ + 1.68) and central points (0), each involving 8, 6 and 2 formulations, respectively. The concentration of active (TH), surfactant (TW) and the pH of the aqueous phase were selected as the independent variables (Table ). PLGA was fixed to 9 mg/mL for the entire experiment. The effect of the independent on the dependent variables (morphology, z-potential and encapsulation efficiency) has been analyzed [47].
Factors and levels of DoE independent variables
Copyright and License information: The Author(s) ©2021 Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.
Do you have any questions about this protocol?
Post your question to gather feedback from the community. We will also invite the authors of this
article to respond.