EFFECT OF PARTICLE SIZE ON THE LYMPHATIC DISTRIBUTION OF 111INDIUM-AMINOPOLYSTYRENE THROUGH INTRAPLEURAL ADMINISTRATION

Abstract

The study examined the impact of sizeon lymphatic particle distribution throughintrapleural (ipl.) administration. Aminopolystyreneof three sizes, 0.29 μm, 2.18 μm, and11.2 μm were radiolabeled with 111Indium andtheir biodistributions were evaluated in ratsafter ipl administration. Animals receivedeither particles of three different sizes (4 mg,200 μCi/animal) or unconjugated 111Indiumas control. The percentage of injected dose(%ID) per organ or sample was determinedfor left (L) and right (R) mediastinal lymphnodes (LN), blood, lung, and pleural wash.The biodistribution of 2.18 μm 111In-aminopolystyrenewas further investigated at 6 h, 24h, 48 h, and 72 h following ipl administrationto examine the possible particle retentiontime. The 2.18 μm particles had significantlyhigher uptake in both LLN and RLNcompared to other sizes. The systemic uptakewas minimal. At 72 h, there was still 3.2 ±3.2% and 2.1 ± 1.8% of injected dose retainedin the LLN and RLN, respectively. Scintigraphicimaging revealed significant accumulationof the radioactivity in mediastinal nodes.Particle size has significant impact onlymphatic particle distribution through ipladministration. Approximately 2 μm seems tobe a suitable size.