Room-temperature phosphorimetry for the determination of trace contaminations of camptothecin in anticancer drugs

Campthotecin derivatives, irinotecan (CPT-11) and topotecan (TPT), have been used for the treatment of cancer and camptothecin (CPT) is a potential contaminant in these anticancer medicines. In this work, room-temperature phosphorimetry was used to quantify either CPT as trace contaminants in anticancer drugs and CPT-11 as the main ingredient in anticancer medicines. Phosphorescence from CPT-11 was induced using Pb(NO3)2 in SDS treated cellulose substrate while CPT was selectively detected using TlNO3 as a phosphorescence enhancer in either cellulose or nylon substrates. The limit of quantification for CPT and CPT-11 was in ng order. A detailed metrological study was made to calculate the combined uncertainty associated to the CPT phosphorescence measurement. Satisfactory analyte recoveries were obtained for CPT-11 as a main active ingredient of a pharmaceutical formulation. The selective determination of CPT in a matrix containing TPT was made using the higher order (2nd) derivative of the excitation spectra. The results demonstrated the applicability of the method due its simplicity, cost effectiveness and selectivity.