Related Experiment Video
Updated: Mar 24, 2026

Development, Characterization, and Evaluation of CAGE-based Ionic Liquid Systems for Transdermal Delivery
Published on: September 26, 2025
Enhancing Effect of Chiral Enhancer Linalool on Skin Permeation of Naproxen
Xia Guo1, Yi Rong1, Liang Zhang1
1Department of Pharmaceutics,Institute of Materia Medica,Zhejiang Academy of Medical Sciences,Hangzhou 310013,China.
Objective:
To investigate the permeation-enhancing effect of dl-linalool, d-linalool, and l-linalool on model drugs across excised rat skin and the effect of linalool on the ceramides in stratum corneum lipids.
Methods:
In vitro skin permeation studies were performed with Valia-Chien diffusion cells, and the permeation samples were analyzed by high performance liquid chromatography with chiral stationary phase. Infrared spectroscopy was used to investigate the effect of linalool on stratum corneum lipids.
Results:
When the donor vehicles added with 1% dl-linalool, 1% d-linalool, or 1% l-linalool, the steady-state skin permeation rate of naproxen was (2.47±0.63), (1.53±0.54), (1.73±0.48) μg·cm(-2)·h(-1), respectively, which is 2.49, 1.55, and 1.75 times (all P<0.05) compared with control group [(0.99±0.42)μg·cm(-2)·h(-1)], and the differences were statistically significant (all P<0.05). The permeation-enhancing effect of dl-linalool on naproxen was found significantly greater than that of d-linalool and l-linalool (both P<0.05). Compared with the control group, the stratum corneum treated with dl-linalool shifted to higher wave number on 2.09 cm(-1) of asymmetric CH2 stretching vibrations in attenuated total reflection-fourier transform infrared spectroscopy analysis. However, stratum corneum treated with d-linalool and l-linalool did not display this phenomenon.
Conclusion:
The disturbing degree of dl-linalool on stratum corneum lipids (ceramides) is different from that of linalool enantiomers, suggesting their different enhancing effect on the same drug.
Related Concept Videos
Chirality in Nature
Bioavailability Enhancement: Drug Permeability Enhancement
Factors Affecting Dissolution: Drug Permeability, Stability and Stereochemistry
Racemic Mixtures and the Resolution of Enantiomers
Properties of Enantiomers and Optical Activity
Indirect-Acting Cholinergic Agonists: Pharmacokinetics
Reversible agents containing quaternary amines, such as neostigmine and edrophonium, are not easily absorbed orally because they...

