Preparation and purification of novel phosphatidyl prodrug and performance modulation of phosphatidyl nanoprodrug

Abstract Background A novel phosphatidyl nanoprodrug system can be selectively released parent drugs in cancer cells, triggered by the local overexpression of phospholipase D (PLD). This system significantly reduces the intrinsic disadvantages of conventional chemotherapeutic drugs. However, the separation and purification processes of phosphatidyl prodrug, the precursor of phosphatidyl nanoprodrug, have not been established, and the preparation of nanocrystals with good stability and tumor-targeting capability is still challenging. Results In this study, we established a successive elution procedure for the phosphatidyl prodrug—phosphatidyl mitoxantrone (PMA), using an initial ten-bed volume of chloroform/methanol/glacial acetic acid/water (26/10/0.8/0.7) (v/v/v/v) followed by a five-bed volume (26/10/0.8/3), with which purity rates of 96.93% and overall yields of 50.35% of PMA were obtained. Moreover, to reduce the intrinsic disadvantages of conventional chemotherapeutic drugs, phosphatidyl nanoprodrug—PMA nanoprodrug (NP@PMA)—was prepared. To enhance their stability, nanoparticles were modified with polyethylene glycol (PEG). We found that nanoprodrugs modified by PEG (NP@PEG–PMA) were stably present in RPMI-1640 medium containing 10% FBS, compared with unmodified nanoprodrug (NP@PMA). To enhance active tumor-targeting efficiency, we modified nanoparticles with an arginine-glycine-aspartic acid (RGD) peptide (NP@RGD–PEG–PMA). In vitro cytotoxicity assays showed that, compared with the cytotoxicity of NP@PEG–PMA against tumor cells, that of NP@RGD–PEG–PMA was enhanced. Thus, RGD modification may serve to enhance the active tumor-targeting efficiency of a nanoprodrug, thereby increasing its cytotoxicity. Conclusions A process for the preparation and purification of novel phosphatidyl prodrugs was successfully established, and the nanoprodrug was modified using PEG for enhanced nanoparticle stability, and using RGD peptide for enhanced active tumor-targeting efficiency. These procedures offer considerable potential in the development of functional antitumor prodrugs.