Novel Antibacterial Azelaic Acid BioMOFs

The development of metal–organic frameworks (MOFs) for bioapplications has gained great relevance over the last few years, mainly due to their potential as drug carriers and/or imaging agents. Although the bioactive azelaic acid has also been widely used as an antibacterial and anti-inflammatory drug, it presents low solubility, so of utmost importance is the development of more soluble formulations with sustained activity. In this contribution, we prove that new azelaic acid-based metal biomolecule frameworks (BioMOFs) are a viable pathway to achieve this goal. Therefore, five novel MOFs were prepared by a simple, low-cost, and environmentally friendly mechanochemical approach, combining azelaic acid with endogenous cations (i.e., K+, Na+, and Mg2+): [K2(H2AZE)(AZE)] (1), [Na4(HAZE)4] (2), [Na2(AZE)(H2O)] (3), and two different polymorphic forms of [Mg(AZE)(H2O)3] (4) and (5) (where H2AZE - neutral azelaic acid; HAZE - mono-deprotonated azelaic acid; AZE - di-deprotonated azelaic acid). After full structural characterization using single-crystal X-ray diffraction data and other complementary standard solid-state techniques, their thermal and moisture stabilities as well as aqueous solubility were assessed. Finally, their antibacterial activity was evaluated against two Gram-positive bacteria (Staphylococcus aureus and Staphylococcus epidermidis), commonly present on the skin. All MOF materials exhibit good stability and higher solubility than azelaic acid. In addition, BioMOF 1 has shown good antibacterial activity both at pH 5 and 6.5. Thus, 1 has shown to be a promising candidate to further develop new topical formulations of H2AZE.