Adaptive optics stimulated Raman scattering microscopy for topical product pharmacokinetic imaging

Area of Science:

• Biomedical Optics
• Dermatology
• Pharmacokinetics

Background:

• Topical drug delivery requires understanding skin pharmacokinetics for efficacy.
• Stimulated Raman Scattering (SRS) microscopy offers chemically specific skin imaging.
• SRS imaging depth is limited by skin scattering and heterogeneity.

Purpose of the Study:

• Evaluate adaptive optics (AO) for improving SRS signal and imaging depth in skin.
• Quantify topical drug uptake kinetics in deeper skin layers using AO-enhanced SRS.

Main Methods:

• Employed a deformable membrane mirror and simulated annealing algorithm for AO optimization.
• Compared AO-SRS with non-AO SRS in nude mouse ear skin and chicken muscle.
• Performed time-lapse AO-SRS imaging of ruxolitinib uptake in ex vivo human skin.

Main Results:

• AO-SRS showed an 11% increase in signal intensity and >350% increase in contrast.
• Optimized AO mirror shapes improved SRS signal across a range of depths (up to 290 μm).
• AO-SRS successfully imaged topical drug penetration beyond 100 μm in human skin.

Conclusions:

• Adaptive optics significantly enhance SRS microscopy for deeper tissue imaging.
• AO-SRS enables quantitative pharmacokinetic analysis of topical drugs in deeper skin structures.
• This technique holds promise for advancing dermatological drug development and efficacy studies.