Polymeric nanomicelles for sustained delivery of anti-cancer drugs

• Mini-review of cancer therapeutics with focus on nano-based technologies.
• Discussion of authors’ original, unpublished findings on encapsulation of anti-cancer drugs in PEG-block-poly(ester-ether) nanomicelles.
• Tuning of drug release kinetics by hydrolytic degradability of micellar core.
• Determination of drug binding constants to correlate loading and release of drugs.

In the first section of this paper, the existing and emerging nanotechnology-based cancer therapies – nanoparticles, drug conjugates, nanomicelles – are reviewed. In a second part, we present our original and unpublished findings on the sustained release of anti-cancer drugs such as paclitaxel, doxorubicin and camptothecin using block copolymer micelles [PEG-b-poly(dioxanone-co-methyl dioxanone)]. Copolymers with variable lengths of hydrophobic and hydrophilic blocks have been synthesized and successfully loaded with paclitaxel, doxorubicin and camptothecin anti-cancer drugs, with micelles size in the range 130–300 nm. Drug encapsulation efficiencies varied between 15% and 70% depending on drug and copolymer composition. The drug binding constants, which give a good insight into drug encapsulation and release, were evaluated from UV spectroscopy as we reported previously for anti-TB drugs. Through variation of the methyl dioxanone content of the copolymer, our systems can be tailored for sustained release of the different drugs.