Intercalation of Ga3+-salicylidene-amino acid Schiff base complexes into layered double hydroxides: Synthesis, characterization, acid resistant property, in vitro release kinetics and antimicrobial activity

Abstract This study is aimed to evaluate the potential application of a drug delivery system of Ga 3 + complexes in layered double hydroxide, i.e. [Ga(L) 2 ] − -LDH (L represents Schiff base ligands made up of salicylidene with glycine, alanine, tyrosine, phenylalanine, aspartic acid and glutamic acid for complexes 1 – 6 , respectively). The successful intercalation of Ga 3 + complexes into Mg/Al-NO 3 -LDH by delaminating/restacking method was proved by elemental analysis, XRD, FTIR spectra, UV–vis DR spectra, TG analysis and SEM measurements. A monolayer intercalation of 5 and 6 , bilayer of 1 and 3 and trilayer of 2 and 4 in interlayer region of hybrids which have extended gallery height of 11.86–21.22 A were deduced. Better acid resistance than the pristine complexes in wide pH range from 7 to 1 was revealed by UV–vis spectra. The cumulative release profile of Ga 3 + complexes from the hybrids in phosphate buffer (pH 7.4) following first-order kinetics via ion-exchange between guest anions and phosphate anions was established by UV–vis spectra. Antibacterial activity of hybrids with MIC values of 65–137 μmol/L against Pseudomonas aeruginosa was demonstrated by the broth twofold dilution method. These results suggest that LDH is a promising host material for carry and controlled delivery of biologically active Ga 3 + complexes.