Laura Ahola

The NRU assay is a quantitative test to determine the potential biological reactivity of a mammalian cell culture in response to a medical device extract. It is described in Annex A of ISO 10993-5 and is one of the most commonly used methods for medical device cytotoxicity testing. The test item is extracted in cell culture medium, which is suitable for both polar and non-polar extracts. The cells are exposed to the extract, and their viability is assessed after staining with neutral red (NR) solution. The number of viable cells correlates with the color intensity determined by photometric measurements, as non-viable cells do not absorb NR. The medical device is considered non-cytotoxic if the percentage of viable cells is ≥ 70 % of the untreated control.

Determination of osmolarity of liquid samples using a freezing point osmometer according to the European Pharmacopoeia method Ph. Eur 2.2.35. Osmolarity is defined as the number of osmols per liter of liquid, reflecting the total number of dissolved ionic and molecular substances present in the solution in molarity. The results of the analysis are reported in mOsm/L. NOTE: The total concentration of the solute in the product needs to be provided (expressed in g/mL), as this information is necessary for the calculation of osmolarity. Without this information, only the product's osmolality (mOsm/kg) can be determined. If the product is a powder, please provide instructions for the preparation of the solution. Analysis can also be performed under GMP - please ask us for an offer.

The osmolality of liquid samples is determined using a freezing point osmometer according to the Ph. Eur 2.2.35 or USP <785> method. Osmolality is the number of osmols per kilogram of liquid, and it reflects the total number of dissolved ionic and molecular compounds present in a kilogram of solution. The results of the analysis are reported in mOsm/kg. The analysis includes the determination of relative density, as the value is necessary to calculate osmolality. NOTE: If the product is in powder form, please provide instructions for preparing the solution. Analysis can also be performed under GMP - ask for an offer from our experts.

We offer comprehensive test packages for verifying the quality of type II and type IIR face masks according to the EN 14683 standard. The tests included in the packages are required to label face masks with the CE marking. Medical face masks are divided into Types I and II according to their bacterial filtration efficiency. Type I masks are not intended for healthcare professionals, but for the public to prevent the spread of infectious diseases. Type II masks are further classified based on whether they are splash-resistant (Type IIR) or not (Type II). To comply with the European Standard EN 14683, Type II face masks must undergo the following quality tests: Bacterial filtration efficiency (BFE) - The ability of the face mask to filter the bacterium Staphylococcus aureus. The BFE is expressed as the percentage of colony-forming units (cfu) that have passed via aerosol through the facemask. If a face mask consists of two or more areas with different characteristics, these areas will be tested separately., Breathability (Differential pressure) - The amount of differential pressure required to draw air through a measured surface area at a constant flow rate., Microbial cleanliness (Bioburden) - The measurement of colony forming units per gram as per EN ISO 11737-1., Biocompatibility - The medical face mask manufacturer shall complete a biocompatibility evaluation according to ISO 10993-1 as a surface device with limited contact. The applicable toxicology testing regimen shall also be determined.. In addition to the above, Type IIR masks require the following test: Splash resistance - Performed according to ISO 22609, this test determines the ability of a face mask to resist penetration of splashes of liquid at different pressures.. The lower displayed price applies to the Type II mask test package, while the higher price also includes the splash resistance test required for Type IIR masks.