Experimental and modeling approaches to determine drug diffusion coefficients in artificial mucus

Area of Science:

• Pharmacokinetics and Drug Delivery
• Biophysical Chemistry
• Respiratory Medicine

Background:

• Asthma involves mucus accumulation, hindering drug penetration and efficacy.
• Effective asthma treatment requires understanding drug diffusion through mucus barriers.
• Current methods for assessing drug diffusion can be invasive or time-consuming.

Purpose of the Study:

• To determine the diffusion coefficients of theophylline and albuterol in artificial mucus.
• To establish a rapid, non-invasive method for evaluating drug diffusion through mucus.
• To model drug concentration profiles within a mucus layer.

Main Methods:

• Utilized time-resolved Fourier transform infrared spectroscopy (FTIR) to monitor drug diffusion.
• Employed Beer's Law to correlate spectral peak changes to drug concentration.
• Applied Fick's 2nd Law of Diffusion and Crank's solution for data analysis.

Main Results:

• Obtained diffusion coefficients: 6.56 x 10^-6 cm²/s for theophylline and 4.66 x 10^-6 cm²/s for albuterol.
• Experimental results closely matched literature values obtained through other techniques.
• Validated a novel approach for measuring drug diffusivity in complex biological media.

Conclusions:

• The developed FTIR-based method provides accurate and efficient assessment of drug diffusion through mucus.
• This technique offers a valuable tool for optimizing drug formulations for pulmonary delivery in asthma.
• Understanding drug diffusion coefficients is crucial for improving therapeutic outcomes in respiratory diseases.