MTX/LDHs hybrids synthesized from reverse microemulsions: Particle control and bioassay study

Abstract

Reverse microemulsions have been used to control the growth of methotrexatum intercalated layered double hydroxides (MTX/LDHs) hybrids, and the influence of reaction temperature, water content (noted as ω) and MTX content (noted as R) on the properties of MTX/LDHs was systematically investigated. The synthesized hybrids were then characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and atomic force microscopy (AFM), etc. XRD and FTIR investigations manifest the successful intercalation of MTX anions into the interlayer of LDHs. The process of particle control has been explored emphatically, and it was found that temperature, water content, and addition of solutes can determine the structural evolution as well as the size of the “water pools” in the reverse microemulsions, while ω plays a critical role in the particle growth. Then in vitro release tests of all hybrids in pH 7.4 phosphate buffered saline (PBS) were explored, and the parabolic diffusion model simulate the release progress best, showing that the release process belongs to multi phase diffusion process via ion exchange. At last, the anticancer efficacy of all MTX/LDHs hybrids was also estimated by MTT assay with the human lung cancer (A549). It is found for the first time that the drug efficacy is closely associated with dispersion coefficient (noted as ϵ).