We have previously developed a charcoal suspension for injection into human
breast cancers in order to facilitate their location during surgery. We ob
served that charcoal particles were ingested by intra and peritumoral macro
phages, some of which carried the particles at some distance from the injec
tion site. We studied the influence of the formulation parameters of the ch
arcoal suspension for intratumoral injection on in vitro and in vivo activa
tion and in vivo mobilization of mouse peritoneal macrophages after intra-p
eritoneal injection of 2 mt of each preparation. The influence of the charc
oal origin (peat vs wood), granulometry, suspension vehicle (water for pare
nteral injection, vs saline), concentration and excipients were studied. Mi
cronized peat charcoal in water for injection at the highest studied concen
tration reduced macrophage activation in vitro and in vivo. However, macrop
hage mobilization was weaker than after thioglycolate injection and did not
seem to be charcoal dose-dependent. The additives incorporated in the char
coal suspension led in vivo to increased peritoneal macrophage activation a
nd mobilization (mannitol, and glucose), only increased activation (polysor
bate 80 and pluronic F68) or mobilization (dextran 40, egg lecithin, and ca
bosil), or inhibited both activation and mobilization (cremophor EL).