Mg-Al Layered Double Hydroxide Nano-Carrier for Controlled Release of anti-inflammatory Drug

Abstract

Layered double hydroxides (LDHs), have been known for many decades as a catalyst and ceramic precursors, traps for anionic pollutants, and additives for polymers. Recently, their successful synthesis on the nanometer scale opened up a whole new field for their application in nanomedicine. Here we report the efficacy of Mg1-xAlx (NO3) x (OH)2 LDH nanoparticles as a carrier and for controlled release of one of the non-steroidal anti-inflammatory drugs (NSAID), sodium salicylate. Mg1-xAlx (NO3)x(OH)2.nH2O nanoparticles were synthesized using co-precipitation method from an aqueous solution of Mg(NO3)2.6H2O and Al(NO3)3.9H2O. Salicylate was intercalated in the interlayer space of Mg-Al LDH after suspending nanoparticles in 0.0025(M) HNO3 and 0.75 (M) NaNO3 solution and using anion exchange method under N2 atmosphere. The shift in the basal planes like (003) and (006) to lower 2θ value in the XRD plot of intercalated sample confirmed the increase in basal spacing in LDH, which is because of intercalation of salicylate into the interlayer space of LDH. FTIR spectroscopy of SA-LDH nano hybrid revealed a red shift in the frequency band of carboxylate group in salicylate indicating an electrostatic interaction between cationic LDH sheet and anionic drug. Differential thermal analysis of LDH-SA nanohybrid indicated higher thermal stability of salicylate in the intercalated form into LDH as compared to its free state.DLS studies showed a particle size distribution between 30-60 nm for pristine LDH whereas salicylate intercalated LDH exhibited a particle size distribution between 40-80 nm which is ideal for its efficacy as a superior carrier for drugs and biomolecules.The cumulative release kinetic of salicylate from MgAl-LDH–SA hybrids in phosphate buffer saline (PBS) at pH 7.4 showed a sustained release of salicylate up to 72 h. The drug release kinetic closely resembled first order release kinetics through a combination of drug diffusion and dissolution of LDH under physiological conditions.The hemocompatibility tests performed on the samples showed that Mg Al LDH was compatible with human blood. Cytotoxicity of LDH-SA nanohybrid was determined using MTT assay, subsequently the DNA fragmentation test on human kidney cells. The results suggest that SA intercalated into LDH was much less cytotoxic than the bare SA on kidney cells.