Novel synthetic approach for accessing drug–dye conjugates for targeted tumour therapy

The use of heptamethine cyanine dyes (HMCD) as a vehicle for targeted delivery of drugs to cancer tissues shows promise. The synthesis of drug–dye conjugates is hampered by scalability and purification issues. Herein we disclose synthetic procedure to procure such drug–dye conjugates that avoid the formation of undesired side products. This novel procedure also avoids the use of HPLC, thereby improving the yield and scalability of such drug–dye conjugates. Improving the atom-efficient coupling of drugs to HMCDs, will facilitate the clinical translation of HMCDs as a drug-delivery system for targeted tumour therapies.