Polymer Nanoparticle for Oral Anticancer Drug Delivery
One of the problems that cancer patients face is that many of the most potent anticancer therapies can be administered only by injection, which means that cancer patients must travel to receive their medication. But thanks to a new type of nanoparticle developed by researchers at the Johns Hopkins University School of Medicine, future cancer patients may be able to receive their medication in pill form.
Anirban Maitra, M.D., and colleagues developed the new polymeric nanoparticle from three different starting materials that they then linked together in various proportions. The investigators found that nanoparticles made of six parts N-isopropylacrylamide, two parts methylmethacrylate, and two parts acrylic acid had suitable pharmacological properties. Indeed, nanoparticles of this composition readily incorporated water-insoluble drugs and were capable of delivering those drugs into the bloodstream after oral administration.
In a paper published in the journal Molecular Cancer Therapeutics, the researchers noted that they chose the three starting materials because they expected that the resulting polymers would stick to the mucosal layer in the gastrointestinal tract (GI). This adhesive property gives cells in the GI tract the opportunity to engulf the nanoparticles and ferry them into the bloodstream.
Tests with the anticancer drug rapamycin showed that this formulation had good pharmacokinetic properties in test animals. More importantly, these nanoparticles were able to deliver rapamycin to human pancreatic tumors implanted in the test animals. In fact, assays showed that oral dosing with this nanoparticle formulation triggered the changes in tumor cell biochemistry expected from rapamycin administration. Additional tests showed that even “mega—doses” of empty nanoparticles administered for 4 weeks caused no apparent toxicities.
This work, which was supported in part by the NCI, is detailed in the paper “In vivo characterization of a polymeric nanoparticle platform with potential oral drug delivery capabilities.” Investigators from the University of Delhi and the University Medical Center Utrecht also participated in this study. An abstract of this paper is available from the journal’s Web site.