Correlating the Properties of Antibiotics with the Energetics of Partitioning in Colloidal Self-Assemblies and the Effect on the Binding of a Released Drug with a Target Protein

The effect of selected aminoglycoside antibiotics on human serum albumin antioxidant activity: a spectroscopic and calorimetric comparative study

BACKGROUND

Human serum albumin (HSA) is a valuable component of non-enzymatic and endogenous antioxidant mechanisms. The antioxidant activity of HSA can be modulated by ligands, including drugs. Although this is a central topic in the field of oxidation, there is still a lack of information about the protection against the effects of elevated free radical levels.

METHODS

The aim of this study was to investigate the antioxidant activity of kanamycin (KAN) and neomycin (NEO) and their effect on the antioxidant potential of HSA using spectroscopic and microcalorimetric techniques.

RESULTS

Despite the fact that kanamycin and neomycin interact with HSA, no changes in the secondary structure of the protein have been observed. The analysis of the aminoglycoside antibiotics showed their low antioxidant activity and a synergistic effect of the interaction, probably due to the influence of ligands (KAN, NEO) on the availability of HSA amino acid residues functional groups, such as the free thiol group (Cys-34).

CONCLUSIONS

Based on the spectroscopic and microcalorimetric data, both KAN and NEO can be considered modulators of the HSA antioxidant activity.

Physicochemical insights into the micelle-based drug-delivery of bioactive compounds to the carrier protein

Micelles have ability to encapsulate a wide range of drugs and modulate their delivery to the carrier/target proteins.

Mechanistic insights into encapsulation and release of drugs in colloidal niosomal systems: biophysical aspects

Vesicular systems such as niosomes provide an alternative to improve drug delivery systems. The efficiency of a drug delivery vehicle is strongly dependent on its components which decide its interaction with partitioned drug(s) and locus of site of partitioning. A quantitative understanding of the physical chemistry underlying partitioning of drugs in complex systems of self-assemblies such as niosomes is scarcely available. In order to obtain quantitative mechanistic insights into partitioning and release of drugs [mitoxantrone (MTX) and ketoprofen (KTP)] in systems of niosomes, we have employed ultrasensitive calorimetry, spectroscopy and microscopy to establish correlations between functionality and energetics which could provide guidance towards rational drug design and choice of suitable non-ionic surfactant-based drug delivery vehicles. Electron microscopy and dynamic light scattering (DLS) methods were used for characterization and assessing the morphology of niosomes. We present here a calorimetry-based approach in assessing the partitioning of the anticancer drugs mitoxantrone and ketoprofen in niosomes and their release to human serum albumin (HSA) employing isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC) and comparison with equilibrium dialysis. The thermodynamic signatures and kinetics of release were analyzed to obtain insights into the role of the functional groups on the drugs in the partitioning process. The assessment of thermal and conformational stability of proteins during drug binding and the effect of drug delivery vehicles on proteins is also crucial. To assess these effects, DSC studies on HSA in the presence and absence of drugs and niosomes were also performed. Finally, the efficacy of the system to impact the cell viability of the MDA-MB-231 triple-negative breast carcinoma cell line was analysed using MTT assay.

Vesicular systems such as niosomes provide an alternative to improve drug delivery systems.