Patent blue V encapsulation in liposomes: potential applicability to endolympatic therapy and preoperative chromolymphography.

The water soluble dark blue stain Patent Blue V was incorporated into liposomes to increase its depot properties. Experiments with intraperitoneal and intramuscular application in rats and with intralymphatic injections in rabbits showed a substantial difference between the pharmacokinetics of aqueous and liposomal solutions. Independent of the route of administration, the dye-stain remained much longer in the tissues using liposomes. Most notably, retroperitoneal lymph nodes in rabbits remained dark blue up to 28 days after hindlimb endolymphatic instillation of liposomal patent blue. This vastly superior depot effect may be clinically adaptable for endolymphatic therapy with cytostatic drugs to enhance nodal drug retention and concentration or for preoperative chromolymphography to facilitate nodal visualization at laparotomy.