TheraPy is a collection of Python scripts developed to model the evolution of chemical and physical inhomogeneities—commonly referred to as microstructure—in drug–polymer composite systems used for controlled drug release coatings.
These coatings are widely applied in medical devices where drug delivery must be carefully regulated over time. TheraPy focuses on capturing how microstructure forms during the casting of drug-eluting coatings and how it subsequently evolves during use or when the coating is exposed to a release medium.
Purpose and Scientific Motivation
The central goal of TheraPy is to provide computational tools that help predict the relationships between material composition, processing conditions, resulting microstructure, and final performance of drug delivery systems.
By explicitly modeling these relationships, TheraPy reduces reliance on empirical trial-and-error approaches in materials selection and process design. Instead, it enables a more systematic and efficient strategy for tailoring microstructure in order to achieve specific drug release behaviors.
Development Background
The TheraPy scripts were developed within the Division of Chemistry and Materials Science (DCMS) in the Office of Engineering Laboratories (OSEL) at the Food and Drug Administration’s Center for Devices and Radiological Health (CDRH).
Designed to integrate seamlessly with FiPy, an object-oriented partial differential equation solver, TheraPy leverages FiPy’s numerical infrastructure to simulate coupled transport and phase behavior. The scripts are intended to be used in much the same way as standard FiPy examples, making them accessible to users already familiar with that framework.
Current Modeling Capabilities
At present, TheraPy provides simulation tools for systems composed of three components: drug, polymer, and solvent. These tools allow users to predict microstructure development during the casting process in both one- and two-dimensional geometries.
In addition to modeling microstructure formation, TheraPy includes scripts for predicting drug release behavior in two-dimensional systems. Together, these capabilities enable a consistent description of both manufacturing and in-service performance.
Planned Extensions
Future development of TheraPy is expected to extend the current framework to address more complex material systems and physical phenomena. Planned enhancements include support for:
- three-dimensional simulations,
- systems with an arbitrary number of components,
- crystallization processes,
- chemical bond formation between constituents,
- chemical degradation of system components.
These extensions would further expand the applicability of TheraPy to a broader range of drug delivery and biomaterials research problems.
Documentation and Usability
TheraPy is accompanied by detailed documentation that describes both the underlying theoretical models and practical usage instructions. The documentation is designed to support users in understanding the governing equations, numerical methods, and implementation details of the provided scripts.
After obtaining the code, users can access local versions of the documentation in both HTML and PDF formats, making it suitable for self-study, teaching, or research reference.
Support and Community Interaction
Open discussion of issues related to TheraPy—including usage questions, bug reports, and feature requests — is encouraged through a dedicated user forum. This collaborative approach supports transparency and continuous improvement of the modeling tools.
Terms of Use and Public Domain Status
TheraPy and its accompanying documentation were developed by employees of the United States Food and Drug Administration as part of their official duties. As such, the software is in the public domain and is not subject to copyright protection.
Users are free to use, copy, modify, distribute, and redistribute the software or derivative works without restriction. However, the FDA assumes no responsibility for the use of the software by third parties and provides no guarantees regarding its quality, reliability, or suitability for any particular purpose.
Use of TheraPy does not imply endorsement by the FDA, nor does it confer any advantage in regulatory decision-making. While redistribution and modification are permitted, users are encouraged to acknowledge the original source and clearly indicate any modifications made to derivative versions.