The understanding of drag reduction by injection of polymer solutions requires an adequate and accurate polymer solution preparation process as well as a thorough understanding of the effects that the delivery system might have on the polymer flow. Mass production of polymer solutions for engineering applications could be more cost effective if large batches of highly concentrated polymer solutions are prepared and then diluted to the final concentrations of interest. However, as shown in this study, depending on the type of polymer used this procedure might be more or less adequate. This study also corroborates that the presence of macro-molecular polymer structures induced by injecting highly concentrated polymer solutions into a shear flow translates into a drag increase and substantial degradation endurance especially at high Reynolds numbers in comparison to homogeneous polymer solutions.