REVERSED-PHASE LIQUID-CHROMATOGRAPHIC ANALYSIS OF COENZYME-Q10 AND STABILITY STUDY IN HUMAN PLASMA

The objectives of this study were to design and validate a method for the assay of coenzyme Q10 (CoQ10) in human plasma and to evaluate the stability of CoQ10 in several conditions currently observed for routin e determinations. CoQ10 was extracted from plasma with n-hexane after dissociation from lipoproteins with methanol. Ethoxy-CoQ10 was used as internal standard. CoQ10 was isolated and then quantitated by high pe rformance liquid chromatography (HPLC) using a binary gradient. Linear ity (r = 0.9999), recovery (97 %) and intra- and inter-run precision ( 1.7 and 2.0 % respectively) appeared to be satisfactory. The stability of CoQ10 in crude plasma was tested under various conditions (i.e. si x hours at room temperature, freezing and thawing, storage for up to 2 4 weeks at - 20 degrees C), the stability of CoQ10 in n-hexane extract s was also tested (24 hours in autosampler rack at room temperature). CoQ10 content was found to be unaffected by any of the tested conditio ns.