Amotosalen

Amotosalen is a psoralen derivative used in photochemical pathogen reduction of human blood components, most notably platelet concentrates and plasma. It is employed in conjunction with ultraviolet A (UVA) light to inactivate a broad range of nucleic acid–containing pathogens and leukocytes in transfusable products, helping to reduce the risk of transfusion-transmitted infections and alloimmunization.

The mechanism involves amotosalen intercalating into DNA and RNA. Upon UVA exposure, it forms covalent cross-links with pyrimidine bases, preventing replication and transcription. After irradiation, amotosalen and its photoproducts are substantially removed from the treated product by an adsorption device as part of the processing workflow, yielding a product suitable for transfusion with reduced residual compound exposure.

Applications and regulatory status vary by jurisdiction, but amotosalen-based pathogen reduction is widely implemented in systems designed for platelet concentrates and plasma. The approach is not universally applicable to all blood components, and treatment is generally not used for whole blood in many settings. Regulatory approvals in major markets typically emphasize enhanced safety against a broad spectrum of pathogens, while continuing to require standard donor screening and testing.

Safety and limitations include potential effects on component quality, such as platelet function, and the need to minimize residual amotosalen through processing steps. While the method broadens the protection against pathogens, it does not replace conventional safety measures, and efficacy can vary among different organisms.