Release of molecules from nanocarriers

Area of Science:

• Drug delivery systems
• Nanotechnology
• Physical chemistry

Background:

• Drug and vaccine release from carriers is typically diffusion or dissolution limited.
• Empirical models like Weibull and Korsmeyer-Peppas are used to fit experimental release kinetics.
• Nanocarrier size reduction to ~100 nm can lead to kinetically limited release due to interface-controlled molecular jumps.

Purpose of the Study:

• To present a general kinetic model for drug/vaccine release from structurally heterogeneous nanocarriers.
• To investigate the role of energetic heterogeneity in nanocarrier release kinetics.
• To explain the observed release profiles and their fitting with empirical models.

Main Methods:

• Development of a general kinetic model incorporating energetic heterogeneity.
• Simulation of release kinetics with varying binding energy deviations (4-8 kcal mol⁻¹).
• Analysis of predicted kinetics and their fit to Weibull and Korsmeyer-Peppas expressions.

Main Results:

• Predicted kinetics initially show linear behavior, transitioning to logarithmic with time.
• The model accurately fits predicted kinetics using Weibull or Korsmeyer-Peppas expressions with exponents between 0.6 and 0.75.
• Energetic heterogeneity is demonstrated as a significant factor controlling release kinetics, potentially explaining non-Fickian diffusion observations.

Conclusions:

• Energetic heterogeneity in nanocarriers significantly impacts drug and vaccine release profiles.
• The proposed kinetic model provides a physically grounded explanation for observed release kinetics, including those fitted by empirical models.
• This understanding can aid in the design of advanced nanocarrier systems with controlled release properties.