A facile synthetic strategy for Mg–Al layered double hydroxide material as nanocarrier for methotrexate

Mg–Al layered double hydroxide nanopowders were synthesised by a facile coprecipitation technique at different pH conditions. LDH nanoparticles of higher aspect ratio with an average particle size of 26 nm were obtained at pH 9 whereas a pH of 11.3 resulted in LDH nanoparticles of average size 50 nm with lower aspect ratio and narrower size distribution. LDH–MTX organo–inorganic nanohybrid was produced with an average particle size of 53 nm after intercalation of MTX into the interlayer space of LDH, as evident from the shift of (0 0 3) peak in X-ray diffraction. This was corroborated by the transmission electron micrograph, which showed an increase in average interlayer spacing from 8.00 Å in pristine LDH to 21.4 Å in LDH–MTX nanohybrid. Thermogravimetric analyses showed ∼33.2 wt% MTX loading in the LDH structure. The MTX release profile from Mg–Al LDH–MTX nanohybrid in phosphate buffer saline at pH 7.4 follows Ritger–Peppas kinetics model which demonstrates that the release kinetics is diffusion controlled. An attempt has been made to explain the above observations based on the effect of electrical double layer repulsions on the growth of LDH nuclei, primarily considering significance of the particle morphology in drug delivery application.