1、 The working principle of transdermal diffusion analyzer:

The core principle of transdermal diffusion analyzer is to simulate the skin barrier, allowing active ingredients to permeate from the supply chamber to the receiving chamber through the diffusion process, thereby evaluating its transdermal absorption capacity. Simply put, it's like a 'skin substitute' that helps us test in advance whether ingredients can effectively penetrate the skin.

Specifically, the instrument will fix the ex vivo skin (of human or animal origin) between the supply chamber and the receiving chamber. The supply room contains the components to be tested, while the receiving room simulates the subcutaneous environment of the human body. The ingredients enter the receiving liquid through the skin from the supply room, and by detecting the concentration changes in the receiving liquid, key data such as permeation rate and total amount can be calculated.

The entire process relies on several key principles:

• Diffusion principle: Components move from high concentration to low concentration, and the larger the concentration gradient, the faster the permeation;

• Leakage conditions: The receiving liquid needs to maintain a low concentration to ensure unobstructed diffusion and more accurate measurement;

• Skin simulation: The instrument simulates the real skin barrier through ex vivo skin or artificial membranes to evaluate the penetration ability of ingredients.

This technology is widely used in the research and development of drugs and cosmetics, which can efficiently evaluate the transdermal effect of ingredients and provide scientific basis for product optimization.

IICommonly used membranes in transdermal diffusion experimentsThere are mainly animal skin, synthetic membranes, and 3D recombinant skin models. Let me help you sort out their characteristics and applicable scenarios:

1. Animal skin

• Common types: pigskin, mouse skin, etc.

• Advantages: Similar to the structure of human skin, low cost, high standardization, and recognized by some regulatory agencies.

• Limitations: The thickness of the stratum corneum of pig skin is significantly greater than that of humans, and cell activity is difficult to maintain in the long term, with significant species differences.

2. Artificially synthesized film

• Common type: Strat-M ® Membrane, cellulose acetate membrane, EVA membrane, etc.

• Advantages: Low experimental cost, simple method, easy control, easy to replicate experimental results, providing reliable data for the selection of controlled-release membranes.

• Limitations: The correlation with ex vivo skin and in vivo experiments is still poor, and the results are only of reference significance.

3. 3D recombinant skin model

• Common type: EpiSkin ™、 EpiDerm ™ Wait.

• Advantages: closer to real skin characteristics, mature technology, high standardization, relatively simple operation.

• Limitations: Limited simulation (such as lack of hair follicles/sweat glands), long preparation cycle, high cost, and difficulty in achieving high-throughput detection.

4. Skin organoid chip

• Common type: Multi layer skin model dynamically cultured and self-assembled based on microfluidic technology.

• Advantages: High simulation degree, low cost, short cycle, supporting high-throughput and cross organ interaction research.

• Limitations: High technical complexity and high requirements for the professional abilities of experimental personnel.

5. Other membranes

• Common types: collagen film, polycarbonate film, etc.

• Advantages: Suitable for specific experimental needs, such as collagen transdermal experiments.

• Limitations: Selection should be based on specific experimental objectives and standards.

I hope this information can help you quickly understand the characteristics of different membranes and make appropriate choices based on your experimental needs.