Timely drug delivery from controlled-release devices: dynamic analysis and novel design concepts

Area of Science:

• Pharmacokinetics and Drug Delivery
• Biomaterials Science
• Transport Phenomena

Background:

• Controlling drug release kinetics is crucial for therapeutic efficacy.
• Predicting the time to achieve steady-state flux is essential for designing effective drug delivery systems.
• Understanding transport mechanisms through membranes informs device development.

Purpose of the Study:

• To provide design tools for drug-release devices.
• To control the time to establish steady-state flux and desired delivery rates.
• To analyze passive, heat-aided, and electrically assisted transport through planar membranes.

Main Methods:

• Application of approximate analytical methods to mathematical models.
• Derivation of relationships between system properties and flux response time.
• Investigation of three case studies involving different drug-release scenarios.

Main Results:

• Predicted steady-state benzocaine flux through ethylene-vinyl acetate membranes in 40 minutes using a first-moment time constant approach.
• Calculated 5 hours and 45 minutes to reach a constant amitriptyline HCl delivery rate across human skin under specific electrical current conditions.
• Estimated onset of steady-state flux between 3.4 and 3.5 minutes with temperature gradients across membranes.

Conclusions:

• The developed analytical methods accurately predict drug-flux response times.
• Design tools can effectively guide the development of controlled drug-release devices.
• Theoretical predictions were validated by simulation and experimental data.