Liposol. camptothecin derivative, research name TQ-B3203, is a recently developed investigational antiproliferative agent by our group.The structure of TQ-B3203 is 2-(hexadecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yl 7-ethyl-camptothecin-10-yl succinate, containing an SN-38 component, a trolox component, a succinic acid linker, and a hexadecanol chain.In this study, the process-related impurities of bulk TQ-B3203 were identified, characterized, and synthesized.Seven major impurities were revealed based on the mass spectrum (MS) and NMR (NMR) spectral data.They were characterized as SN-38 (IMP-I), trolox (IMP-II), 2-(dodecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yl 7-ethyl-camptothecin-10-yl succinate (IMP-III), hexadecyl 7-ethyl-camptothecin-10-yl succinate (IMP-IV), 2-(tetradecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yl 7-ethyl-camptothecin-10-yl succinate (IMP-V), 4-(2-(hexadecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yloxy)-4-oxobutanoic acid (IMP-VI), and 4-(2-(octodecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yloxy)-4-oxobutanoic acid (IMP-VII).The probable origin of the impurities from the preparation process of TQ-B3203 was discussed.