Synthesis of nanomaterials using expired medicines: an eco-friendly option

Expired medicines are a burden to the environment. In this paper, a novel method is suggested to reutilize expired medicines in order to assess the possibilities of synthesizing a variety of nanomaterials. To this end, expired flouroquinolone (norfloxacin) and tinidazole combinations were used to synthesize metal (Au), oxide (ZrO₂) and chalcognide (CdS) nanoparticles using for the first time a green chemistry approach. Au, ZrO₂ and CdS nanoparticles are available in convenient sizes of 6 nm, 26 nm and 18 nm, respectively, and remain stable for at least six months. This novel procedure is possible thanks to their molecular organization and elements. The inclusion of a fluorine atom in a drug molecule may influence both the disposition of the drug and its interaction with its pharmacological target; for example, the effects of fluorine substitution on the inter- and intra-molecular forces that affect binding of ligands. The presence of sulfur in the tinidazole molecules may also have contributed towards synthesis through proton withdrawal. The nanomaterials synthesized in this way were characterized using X-ray diffraction analysis and transmission electron microscopy to identify the formation of the desired nanoparticles. This single-step green approach is very convenient, simple and can be extended to synthesize a variety of nanomaterials that might find new technological and pharmaceutical applications.