In vitro UV protection screening pack (SPF + UVA PF + raw IC)

The in vitro UV protection screening package includes all the tests necessary to evaluate the photoprotective performance of a sunscreen product. It comprises the measurement of the in vitro SPF (Sun Protection Factor), the UVA protection factor (UVA PF), and the crude criterion index (CR). These parameters are essential for characterizing the effectiveness of a cosmetic formulation against ultraviolet radiation and ensuring its regulatory compliance before it is placed on the market.

Performed by UV-Vis spectrophotometry on PMMA plates, this test provides a complete, rapid and reproducible evaluation of the overall photoprotection of sunscreens, lotions, gels or sprays.

Objectives and principles of the method

UV radiation (UVA and UVB) is responsible for numerous harmful effects on the skin: burns, photoaging, DNA damage, and oxidative stress. The role of a sunscreen is therefore to effectively reduce the transmission of this radiation through a combination of UV filters and stabilizing agents.

The in vitro UV screening pack allows you to:

• Measuring SPF in vitro, an indicator of protective power against UVB;
• Determine the UVA protection factor (UVA PF), guaranteeing defense against skin aging;
• Calculate the raw IC index, the overall protection ratio taking into account the efficiency and spectral distribution of the filters;
• Verify compliance with the requirements of ISO 24443 (UVA) and ISO 23675 (SPF in vitro);
• Compare different formulations or batches before industrial validation.

Test procedure

The analysis is performed by UV-Vis spectrophotometry , according to a standardized protocol:

1. Application of the tested product onto a PMMA plate (standard substrate reproducing the skin surface);
2. Film drying and stabilization;
3. Measurement of the transmission and absorption of UV radiation over the entire spectrum 290–400 nm;
4. Calculation of SPF, UVA PF and crude IC indices from absorbance curves.

in vitro method , which is non-destructive and reproducible, allows for rigorous scientific evaluation without resorting to trials on volunteers.

Interpretation of results and regulatory compliance

The results obtained are presented in the form of a comprehensive photoprotective assessment report including:

• The average value of SPF in vitro ;
• The UVA protection factor (UVA PF) and the UVA/UVB ratio , an indicator of spectral balance;
• The raw IC , a summary of the overall protection performance;
• The conformity analysis according to European regulations (Regulation EC No. 1223/2009) and COLIPA recommendations.

A sunscreen product is considered compliant when it has a UVA/UVB ratio ≥ 1/3 and a high crude IC , guaranteeing balanced and long-lasting protection.

Industrial applications

This trial pack is essential for:

• Manufacturers of sun care products : validation of the effectiveness of formulas before being placed on the market;
• Cosmetic R&D laboratories : optimization of combinations of UV filters, antioxidants and excipients;
• Natural cosmetic or dermocosmetic brands : verification of the performance of mineral filters (titanium dioxide, zinc oxide);
• Design offices and subcontractors : quality control of production batches or reformulations.

These tests guarantee the safety of use and the marketing credibility of the products, while respecting European regulatory standards.

YesWeLab Expertise and Support

YesWeLab provides you with a network of laboratories specializing in photoprotection and cosmetic analysis. Our partners have calibrated UV-Vis spectrophotometry equipment and follow the standardized protocols ISO 24443 and ISO 23675.

Our experts will assist you with:

• The choice of tests adapted to your products (SPF in vitro, UVA PF, crude IC, photochemical stability, etc.);
• The scientific interpretation of results for labelling and regulatory compliance;
• Optimizing solar formulations in line with your performance objectives and technical constraints.

Thanks to the YesWeLab digital platform, you can manage your analyses, track your samples and view your reports with complete transparency.

Further analyses recommended

For a complete assessment of the quality and stability of your solar products, YesWeLab also recommends:

• UV filter photostability test
• Determination of titanium dioxide and zinc oxide
• Accelerated stability study of cosmetics
• Measurement of the viscosity and texture of emulsions

These additional analyses make it possible to validate the overall performance and stability of sun care products, from formulation to final packaging.