Evaluation of Heat Effects on Fentanyl Transdermal Delivery Systems Using In Vitro Permeation and In Vitro Release...

Area of Science:

• Pharmacology
• Drug Delivery
• Biomedical Engineering

Background:

• Transdermal delivery systems (TDS) offer controlled drug release.
• Understanding thermal effects on TDS is crucial for accurate in vitro testing.
• Fentanyl is a model drug for evaluating transdermal systems.

Purpose of the Study:

• To investigate the impact of experimental conditions on heat effects in transdermal drug delivery.
• To evaluate heat effects on fentanyl TDS using in vitro permeation testing (IVPT) and in vitro release testing (IVRT).
• To determine the influence of heat application timing and duration on fentanyl permeation.

Main Methods:

• Utilized Franz diffusion cells with human skin for IVPT and without skin for IVRT.
• Employed a heating lamp to apply seven different heat application regimens.
• Determined the activation energy of skin permeation for fentanyl using an aqueous solution.

Main Results:

• A temperature increase from 32°C to 42°C doubled fentanyl flux from TDS, consistent with activation energy.
• Heat application onset time and duration significantly affected the magnitude of flux increase.
• Inadequate sampling time points masked heat-induced flux increases, highlighting the need for optimized sampling.

Conclusions:

• Skin acts as the rate-limiting barrier for fentanyl TDS delivery at elevated temperatures.
• Drug release from TDS evaluated by IVRT was rapid.
• Optimized experimental conditions, including sampling, are vital for reliable heat effect evaluation in TDS testing.