antibody production against camptothecin-derived small molecules: a tool for developing pharmacokinetic studies and dose management of chemotherapy

Aim and background: irinotecan and topotecan are camptothecin compounds commonly used for cancer therapy. as the super-cytotoxic form of camptothecin families, sn38 is the active form of all camptothecin derivatives. recently, sn38 has also been used as a payload in new generation of targeted drug delivery systems. pharmacokinetic (pk) studies and side effect management of the aforementioned cancer medicines remain challenges. we aim to overcome this challenge by developing simple methods that are non-invasive and easy to use in routine clinical laboratories.. methods: sn38–20-o-glycine and sn38–20-o-glycine-nhs were synthesized and confirmed by mass, 1h-nmr, and 13c-nmr spectroscopy. two different immunogens were prepared and characterized, including sn38 conjugated with keyhole limpet hemocyanin (klh) protein by coupling sn38 to klh by classical glutaraldehyde coupling reaction, either through its amine-containing sn38–20-o-glycine or sn38–20-o-glycine-nhs derivative. we confirmed and characterized the usefulness of the coupling reactions of haptens (sn38-klh and sn38nhs-klh) by ultraviolet (uv) spectrophotometry and then used them for animal vaccination. antibodies were produced and isotypes determined by enzyme-linked immunosorbent assay (elisa) and purified either with homemade sn38 affinity columns or hitrapby protein g prepacked columns.results and discussion:titers of anti-sn38 were up to-fold higher in animals immunized with sn38nhs-klh than sn38-klh. antiserum from the highest-affinity animal was selected. collecting antiserum (polyclonal and monoclonal antibodies) had high affinity and specificity to its cognate ligand..conclusion: polyclonal and monoclonal antibodies are valuable for developing highly sensitive and selective immunoassays for camptothecin-containing cancer medicines. elisa provides a sensitive and specific tool for developing pharmacokinetic studies, dose monitoring, and side effect management of camptothecin-derived small molecules.