The aim of this study was to prepare anticancer drug-bovine serum albumin (BSA) conjugates using a cross-linker to prepare self-assembling nanoparticles. Irinotecan (IRT) was chosen as a model anticancer drug. N-[p-maleimidophenyl]-isocyanate (PMPI) was chosen as the cross-linker. An IRT-PMPI intermediate containing a maleimide moiety was reacted with the BSA sulfhydryl groups in solution. Residual non-reacted IRT was removed using micro-scale desalting column chromatography. After freeze-drying, the IRT-PMPI-BSA nanoparticles, in the form of a yellow powder, were obtained. The physicochemical properties of the IRT-PMPI-BSA nanoparticles were then investigated using Fourier transform infrared spectroscopy (FT-IR) analysis, dynamic light scattering (DLS), powder X-ray diffraction (PXRD) and transmission electron microscopy (TEM). The critical aggregation concentration (CAC), loading content and encapsulation efficiency of IRT-loaded IRT-PMPI-BSA nanoparticles were measured. FT-IR, PXRD and CAC data confirmed that IRT-PMPI-BSA nanoparticles had been synthesized successfully. TEM and DLS data showed that the nanoparticles formed due to self-assembly of the hydrophobic drug and hydrophilic BSA and that the nanoparticles were spherical and on the nanometer scale. The loading content and encapsulation efficiency of IRT, determined using HPLC, varied with reaction conditions. These IRT-conjugated BSA nanoparticles may be used for targeting of active tumors.
