Photoinactivation of viral and bacterial blood contaminants using halogenated coumarins

A method of inactivating viral, and/or bacterial contaminants in a composition comprising blood, a blood component, cell cultures or a component of a cell culture, comprising the steps of:

• a) mixing said composition in a liquid state with a chemical radiation sensitizer capable of targeting said viral, and/or bacterial contaminants, wherein said sensitizer is a compound of the formula:
• ##STR12## wherein .mu. is an integer from 1 to 6;
• X is an anionic counterion;
• R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are independently halo;
• H;
• linear or branched alkyl of 1-10 carbon atoms;
• linear or branched alkoxy of 1-10 carbon atoms;
• (CH.sub.2).sub.p Z.sup.+ R', R", R'" or --O(CH.sub.2).sub.n Z.sup.+ R', R", R'" where p is an integer from 0 to 10 and n is an integer from 1 to 10 and R', R" and R'" are independently H, or linear or branched alkyl of 1 to 10 carbon atoms, Z is N or P, with the proviso that on each Z atom, not more than two of R', R" and R'" may be H;
• at least one of R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 is (CH.sub.2).sub.p Z.sup.+ R', R", R'" or --O(CH.sub.2).sub.n Z.sup.+ R', R", R'";
• and at least one of R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 is halo;
• and
• b) exposing said composition and sensitizer to ultraviolet radiation sufficient to activate said sensitizer whereby the activation of said sensitizer inactivates said contamination in said composition.