Enhanced Analytic Approach for Describing pH Triggered Fast Drug Release Systems

Abstract

Background: pH sensitive dendrimers attached to nanocarriers, as one of the drug release systems, has become quite popular due to their ease of manufacture in experimental conditions and ability to generate fast drug release in the targeted area. This kind of fast release behavior cannot be represented properly most of the existing kinetic mathematical models. Besides, these models have either no pH dependence or pH dependence added separately. So, they have remained one dimensional. Objective: The aim of this study was to establish the proper analytic equation to describe the fast release of drugs from pH sensitive nanocarrier systems. Then, to combine it with the pH dependent equation for establishing a two-dimensional model for whole system. Methods: We used four common kinetic models for comparison and we fitted them to the release data. Finding that, only Higuchi and Korsmeyer-Peppas models show acceptable fit results. None of these models have pH dependence. To get a better description for pH triggered fast release, we observed the behavior of the slope angle of the release curve. Then we puroposed a new analytic equation by using relation between the slope angle and time. Result: To add a pH dependent equation, we assumed the drug release is “on” or “off” above/below specific pH value and we modified a step function to get a desired behavior. Conclusion: Our new analytic model shows good fitting, not only one-dimensional time dependent release, but also two-dimensional pH dependent release, that provides a useful analytic model to represent release profiles of pH sensitive fast drug release systems.

Locust bean gum‐polyvinyl alcohol hydrogels: Synthesis, characterization, swelling behaviors, and mathematical models

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“…Because diffusion-based models are more likely able to predict swelling. Also, a new analytic approach is added to the modeling calculations for better comparison and prediction comments on the swelling behavior 53 Equation (9). In some cases, swelling of the substance might be very fast and traditional predictive models can not fit well enough.…”

“…In this kind of case, fast models might be more useful compared to traditional models because of their predictive ability. 53,55 That's why it is added Equation ( 9) for comparison to other models. And the results showed that fast models are more promising compared to other ones while swelling in the related experiment.…”