Fig. 1

In vivo pharmacokinetic characteristics of TransCon TLR7/8 Agonist. A TransCon TLR7/8 Agonist was designed as a sustained-release prodrug of resiquimod consisting of resiquimod bound, at multiple conjugation sites, to a suspension of polymeric PEG hydrogel microspheres via a covalent and cleavable linker (R = resiquimod; L = linker). B Male Wistar rats (n = 3/group) received a single subcutaneous injection of either soluble resiquimod (25 μg) or TransCon TLR7/8 Agonist [25 μg equivalent (eq.) of resiquimod]. Blood was withdrawn and used for plasma generation over 28 days. The resiquimod concentration in the plasma samples was quantified by LC–MS/MS. Values are represented as mean resiquimod concentration (pg/ml) per group ± SEM. C Female BALB/c mice were SC implanted with 3 × 10⁵ CT26 tumor cells in their flank. When tumors were grown to a mean tumor volume of ~ 115 mm³, mice were randomized into treatment cohorts (Day 0). The day following randomization, animals received 5 or 20 μg (eq. of resiquimod) of TransCon TLR7/8 Agonist as a single intratumoral dose. Blood was withdrawn (n = 3/time point) and used for plasma generation at 6 h, 3 days and 7 days. The resiquimod concentration in the plasma samples was quantified by LC–MS/MS. Values are represented as mean resiquimod concentration (pg/ml) per dose group ± SEM