Aim: A procedure was developed for the assessment of photochemical stability of drugs in blood and plasma under standardized conditions. The procedure avoids a variable outcome of photochemical stability experiments and tests relevant worst case conditions so that unnecessary light protection is avoided. Results/methodology: Blood and plasma were spiked with a mixture of drugs and incubated in a Suntest CPS(+), in the laboratory on the bench and near the window on a sunny summer day. The results were compared.
Discussion/conclusion: No protection from light, limited protection from light and full protection from light are advised for drugs that are stable in plasma in the Suntest CPS(+) at 250 W/m(2) for at least 30 min, for 5-30 min and for <5 min, respectively.
Keywords: LC–MS/MS; bioanalysis; blood; method validation; photochemical degradation; plasma.