Untargeted Large Volume Hyperthermia Reduces Tumor Drug Uptake From Thermosensitive Liposomes

Area of Science:

• Pharmacology
• Biomedical Engineering
• Oncology

Background:

• Thermosensitive liposomes (TSL) are designed for targeted drug delivery.
• The influence of hyperthermia (HT) on TSL drug release and tumor uptake requires further investigation.

Purpose of the Study:

• To investigate the impact of different hyperthermia (HT) methods on tumor drug uptake using TSL-encapsulated doxorubicin (TSL-DOX).
• To compare the efficacy of thermistor probe (T), laser (L), and water bath (WB) HT methods.
• To evaluate the effect of HT duration (15 min vs. 60 min) on drug delivery.

Main Methods:

• Development of realistic 3-D computer models simulating TSL-DOX delivery in tumors.
• Simulation of three HT methods (T, L, WB) with varying durations.
• Corroboration of model predictions with in vivo studies.

Main Results:

• Computer models predicted higher drug concentrations with longer HT durations for T (21.0 μg/g) and L (25.2 μg/g) methods at 60 min.
• In vivo studies showed increased tumor fluorescence with extended HT duration for T (2.6x) and L (1.6x) (p < 0.05).
• Water bath (WB) HT resulted in rapid depletion of TSL-DOX in circulation, leading to poor tumor drug uptake.

Conclusions:

• Targeted, localized HT methods (T and L) improve TSL-DOX tumor uptake, especially with longer durations.
• Large-volume, untargeted HT (WB) is ineffective and leads to systemic drug loss.
• Optimizing HT parameters is crucial for effective TSL-based cancer therapy.