Recent advances in nanomaterial delivery systems to administer metformin for cancer therapy

Recently, an increasing number of studies and clinical trials have associated an antidiabetic drug metformin (Met) with reduced risks of cancer. Moreover, a potential of Met as an adjuvant to conventional therapies of cancer treatment has been highlighted as well. Nevertheless, the unfavorable pharmacological properties of Met can hinder its efficacy in cancer treatment. To overcome this challenge, drug delivery systems (DDSs) based on various nanomaterials (NMs) have been implemented to entrap Met with or without other therapeutic agents. This review will provide a detailed overview of Met entrapment in NMs for cancer therapy, which will include lipid-based NMs, polymer-based NMs, and inorganic-based NMs. These studies have highlighted the advantage of entrapping Met, achieving sustained drug release, enhanced accumulations of the drug at the tumor sites, as well as enhanced efficacy of therapies compared to their free drug forms.