Related Experiment Video
Updated: Jun 15, 2026
06:24
Minimal Erythema Dose (MED) Testing
Published on: May 28, 2013
In vitro sun protection factor: still a challenge with no final answer
1Institut Dr. Schrader Hautphysiologie, Holzminden, Germany. Mathias.Rohr @ Schrader-Institute.de
Skin Pharmacology and Physiology
|March 11, 2010
Summary
Developing reliable in vitro sun protection factor (SPF) testing remains challenging. While this study reduced within-lab variability for SPF measurements, it did not improve inter-lab comparisons, highlighting the need for further research.
Area of Science:
- Dermatology
- Photobiology
- Cosmetic Science
Background:
- In vitro methods for determining sun protection factor (SPF) are sought after but lack broad acceptance.
- Existing methods face challenges due to sunscreen composition variability, device limitations, and reproducible application difficulties.
Purpose of the Study:
- To compare methodologies and strategies for in vitro sun protection factor (SPF) testing.
- To identify technical factors influencing in vitro SPF measurement accuracy and reproducibility.
Main Methods:
- A multicenter study was conducted to measure in vitro data comparing different SPF testing approaches.
- Key parameters influencing transmission measurements were analyzed, including spectrophotometer quality, product application, sample pretreatment, equilibration conditions, and data calculation.
Main Results:
- A reduction in standard deviations for in vitro SPF testing was achieved within individual laboratories.
- No significant improvement in inter-laboratory comparisons was observed, indicating persistent challenges in standardization.
Conclusions:
- Developing a valid and reliable in vitro SPF test method remains a significant challenge.
- Further research and development are necessary to overcome technical hurdles and establish a satisfactory in vitro SPF testing protocol.
Related Concept Videos
01:23Role of Skin in Vitamin D Synthesis
The skin plays a crucial role in the synthesis of vitamin D, a vital nutrient for various physiological processes in the body. Vitamin D is unique because it can be synthesized in the skin through a series of chemical reactions triggered by exposure to ultraviolet B (UVB) radiation from sunlight.
The solar UV B rays (290-315 nm) are absorbed by the skin, and 7-dehydrocholesterol (provitamin D3) photolyzes it to previtamin D3, which undergoes a rapid transformation to vitamin D3(cholecalciferol).
The solar UV B rays (290-315 nm) are absorbed by the skin, and 7-dehydrocholesterol (provitamin D3) photolyzes it to previtamin D3, which undergoes a rapid transformation to vitamin D3(cholecalciferol).
01:16In vitro Mutagenesis
To learn more about the function of a gene, researchers can observe what happens when the gene is inactivated or “knocked out,” by creating genetically engineered knockout animals. Knockout mice have been particularly useful as models for human diseases such as cancer, Parkinson’s disease, and diabetes.
01:27Acne Infection
Acne is a multifactorial skin condition primarily affecting adolescents and young adults, with a global prevalence estimated to exceed 75% in this demographic. The condition is characterized by the formation of comedones (blackheads and whiteheads), papules, pustules, nodules, and, in severe cases, cysts, particularly in areas rich in sebaceous glands such as the face, neck, chest, and back. The pathogenesis involves increased sebum production, follicular hyperkeratinization, colonization by...