Combination chemotherapy is frequently used in the clinic for
cancer treatment; however, associated adverse effects to normal tissue may limit its therapeutic benefit. Nanoparticle-based
drug combination has been shown to mitigate the problems encountered by free
drug combination therapy. Our previous studies have shown that the combination of two anticancer drugs,
doxorubicin (DOX) and
mitomycin C (MMC), produced a synergistic effect against both murine and human
breast cancer cells in vitro. DOX and MMC co-loaded
polymer-
lipid hybrid nanoparticles (DMPLN) bypassed various efflux transporter pumps that confer multidrug resistance and demonstrated enhanced efficacy in
breast tumor models. Compared to conventional
solution forms, such superior efficacy of DMPLN was attributed to the synchronized pharmacokinetics of DOX and MMC and increased intracellular
drug bioavailability within
tumor cells enabled by the nanocarrier PLN. To evaluate the pharmacokinetics and bio-distribution of co-administered DOX and MMC in both free
solution and nanoparticle forms, a simple and efficient multi-
drug analysis method using reverse-phase high performance liquid chromatography (HPLC) was developed. In contrast to previously reported methods that analyzed DOX or MMC individually in the plasma, this new HPLC method is able to simultaneously quantitate DOX, MMC and a major cardio-toxic DOX metabolite,
doxorubicinol (DOXol), in various
biological matrices (e.g., whole blood,
breast tumor, and heart). A dual fluorescent and ultraviolet absorbent probe
4-methylumbelliferone (4-MU) was used as an internal standard (I.S.) for one-step detection of multiple
drug analysis with different detection wavelengths. This method was successfully applied to determine the concentrations of DOX and MMC delivered by both nanoparticle and
solution approaches in whole blood and various tissues in an orthotopic
breast tumor murine model. The analytical method presented is a useful tool for pre-clinical analysis of nanoparticle-based delivery of
drug combinations.