Despite increasing use of dietary supplements, clinical pharmacological data are often missing. Various form of omega-3 Long Chain Polyunsaturated Fatty Acids (n-3 LC-PUFA), already present in the daily diet, are used with a wide range of clinical objectives.
  To evaluate the bioequivalence of two n-3 LC-PUFA ethyl ester preparations, previously shown not be bioequivalent in healthy subjects, with the objective of providing a guideline for future work in this area.

  A randomized double blind crossover protocol was chosen; volunteers were selected with the lowest blood levels of n-3 LC-PUFA among candidates. They received the ethyl esters in a single high dose (12 g) and EPA and DHA blood levels were analyzed after fingerprick collection at intervals up to 24 hours.

  Differently from a prior study, the pharmacokinetic analysis indicated a satisfactory bioequivalence: for the AUC(0-24 ) 90% CI of the ratio between the two formulations are in the range for bioequivalence (for EPA 0.98 - 1.04 and for DHA 0.99 - 1.04), same for C(max) and Tmax (90% CI are 0.95-1.14; 1.10-1.25 for both EPA and 0.88-1.02; 0.84-1.24 for DHA).

  This study shows that, in order to obtain reliable bioequivalence data of products present in the daily diet, certain conditions should be met. Subjects should have low, homogeneous baseline levels and not be exposed to food items containing the product under evaluation, eg fish. Finally, as in the case of Omega-3 FA, selected doses should be high, eventually with appropriate conditions of intake.